Fuel Pressure Regulator 2 Control Circuit Open

Symptoms and Severity

Excessive fuel pressure can lead to various driving issues, as well as internal damage to the engine and catalytic converter. For this reason, a P2294 code should be classified as severe.

Symptoms of a P2294 code may include:

  • Delayed starting
  • Black smoke from the exhaust system
  • Reduced fuel efficiency
  • Engine driveability codes may also accompany a P2294

Causes

Potential causes for this code being set are as follows:

  • Shorted or open wiring or connectors in the fuel pressure regulator control circuit
  • Faulty fuel pressure regulator
  • Faulty fuel rail pressure sensor
  • Incorrect PCM or PCM programming error

Diagnostic and Repair Procedures

A diagnostic scanner, digital volt/ohmmeter (DVOM), appropriate fuel pressure gauge, and a reliable vehicle information source (such as All Data DIY) will be needed to diagnose a P2294 code.

NOTE: Be extremely careful when connecting a manual pressure gauge. High-pressure fuel coming into contact with hot surfaces or an open spark can ignite and cause a dangerous fire.

I normally start with a visual inspection of the system’s wiring and connectors; focusing my attention on the harnesses and connectors on top of the engine. The heat associated with this area makes it popular with pests in cold climates. These pests can damage (chew) the system’s wiring and connectors.

Connecting the scanner to the vehicle’s diagnostic port and retrieving stored codes and freeze frame data would be my next task. I write down this information as it may be useful during the diagnostic process. Now, I would clear the codes and test the vehicle if possible.

If the code immediately resets, check the voltage and ground at the fuel pressure regulator. If no voltage is found, test the power relays and fuses following the wiring diagram derived from the vehicle information source. If there is no ground, follow the wiring diagram to locate the appropriate ground(s) for the fuel pressure regulator control system and ensure all are secure.

If there is voltage and ground at the fuel pressure regulator control, obtain the fuel pressure specifications from your vehicle information source and test the fuel system pressure using the fuel pressure gauge. Carefully follow the manufacturer’s recommendations for connecting the fuel pressure gauge. Observe the fuel system data using the scanner while visually monitoring the manual fuel pressure with the fuel gauge. If the fuel pressure reflected on the scanner data display does not match the actual fuel pressure, suspect a faulty fuel pressure sensor.

Fluctuations in actual fuel pressure should occur with variations in the fuel pressure regulator control voltage. If not, suspect that the fuel pressure regulator is faulty, there is an open or short circuit in one of the fuel pressure regulator control circuits, or the PCM is faulty.

Follow the manufacturer’s recommendations for testing the electronic fuel pressure regulator and individual fuel pressure regulator control circuits with the DVOM. Disconnect controllers from the circuit before testing with the DVOM to avoid damaging control modules.

Additional Diagnostic Notes:

The fuel rail and associated components may be under high pressure. Be cautious when removing the fuel pressure sensor or fuel pressure regulator
Turn the ignition switch to OFF to connect/disconnect the fuel pressure gauge

P2295 Low Fuel Pressure Regulator 2 Control Circuit

Symptoms and Severity

Since excessive fuel pressure can lead to various driving issues and damage internal engine components and the catalytic converter, a P2295 code should be considered serious.

Symptoms of a P2295 code may include:

  • Delayed starting when the engine is cold
  • Black smoke from the exhaust system
  • Reduced fuel efficiency
  • Engine misfire codes and idle control codes may also accompany a P2295

Causes

Potential causes for this code setting are as follows:

  • Shorted or open wiring or connectors in the fuel pressure regulator control circuit
  • Faulty fuel pressure regulator
  • Defective fuel rail pressure sensor
  • Incorrect PCM or PCM programming error

Diagnostic and Repair Procedures

To diagnose a P2295 code, a diagnostic scanner, digital volt/ohmmeter (DVOM), appropriate fuel pressure gauge, and a reliable source of vehicle information (such as All Data DIY) will be required.

NOTE: Extreme caution must be exercised when using a fuel pressure gauge. High-pressure fuel coming into contact with hot surfaces or an open spark could ignite and cause a fire.

I prefer to start with a visual inspection of the system’s wiring and connectors; focusing my attention on the harnesses and connectors on top of the engine. The warm area of the upper engine makes it popular with pests in cold climates. These pests often chew on system wiring and connectors.

Connect the scanner to the vehicle’s diagnostic port and retrieve stored codes and freeze frame data. Note this information as it will prove useful if the diagnostic process becomes prolonged. Clear the codes and test the vehicle if possible.

If the code immediately resets, check for proper voltage level and battery ground at the fuel pressure regulator. If no voltage is found, test the power relays and fuses following the wiring diagram derived from the vehicle information source. If there is no ground, the wiring diagram can help locate the ground locations of the fuel pressure regulator control system and ensure they are secure.

The presence of voltage and ground at the fuel pressure regulator control would prompt me to obtain fuel pressure specifications from the vehicle information source, then test the fuel system pressure using the fuel pressure gauge. Always follow manufacturer recommendations for using the fuel pressure gauge. Use the scanner to observe fuel system data while visually monitoring manual fuel pressure with the fuel gauge.

Suspect a faulty fuel pressure sensor if the fuel pressure level reflected on the scanner does not match the actual fuel pressure. Variations in the fuel pressure regulator control voltage should reflect fluctuations in actual fuel pressure. If this does not occur, suspect that the fuel pressure regulator is faulty, there is an open or short circuit in one of the fuel pressure regulator control circuits, or the PCM is defective.

Use the DVOM and follow manufacturer recommendations to test the electronic fuel pressure regulator and individual fuel pressure regulator control circuits. To avoid damaging control modules, disconnect controllers from the circuit before testing circuit resistance and continuity with the DVOM.

Additional Diagnostic Notes:

The fuel rail and associated components may be under high pressure. Be cautious when removing the fuel pressure sensor or fuel pressure regulator
Fuel pressure tests should be performed with the ignition switch in the key on engine off (KOEO) position

P2296 Fuel Pressure Regulator 2 Control Circuit High

Symptoms and Severity

Since excessive fuel pressure can damage the internal engine and catalytic converter and lead to various driving issues, a P2296 code should be classified as severe.

Symptoms of a P2296 code may include:

  • Engine misfire codes and idle control codes may also accompany a P2296
  • Reduced fuel efficiency
  • Delayed starting when the engine is cold
  • Black smoke from the exhaust system

Causes

Potential causes for this code definition include:

  • Faulty fuel pressure sensor
  • Faulty fuel pressure regulator
  • Shorted or open wiring or connectors in the fuel pressure regulator control circuit
  • Incorrect PCM or PCM programming error

Diagnostic and Repair Procedures

Diagnosing a P2296 code will require access to a diagnostic scanner, a digital volt/ohmmeter (DVOM), an appropriate fuel pressure gauge, and a reliable vehicle information source (such as All Data DIY).

NOTE: Extreme caution must be exercised when using a manual pressure gauge. High-pressure fuel coming into contact with hot surfaces or an open spark could ignite and cause a fire.

A visual inspection of the system’s wiring and connectors, focusing on the harnesses and connectors on top of the engine, has been successful for me in the past. It seems that the hot area of the upper engine is popular with pests, especially in cold climates. Unfortunately, pests often repeatedly chew on the system’s wiring and connectors.

Next, I would connect the scanner to the vehicle’s diagnostic port and retrieve stored codes and freeze frame data. Writing down this information can be helpful if the diagnostic process becomes prolonged. Clear the codes and test the vehicle if the engine starts.

Check for proper voltage level and battery ground at the fuel pressure regulator if the code resets. If no voltage is detected at the fuel pressure regulator connector, test the power relays and fuses by following the appropriate wiring diagram from the vehicle information source. If there is no ground, the wiring diagram can help you locate the ground points of the fuel pressure regulator control system and ensure they are secure.

Proper voltage and ground circuits found at the fuel pressure regulator control connector would lead me to obtain fuel pressure specifications from the vehicle information source and test the fuel system pressure using the fuel pressure gauge. Remember to follow the manufacturer’s recommendations for using the fuel pressure gauge.

Monitor the manual fuel pressure with the fuel gauge while using the scanner to observe the fuel system data. A faulty fuel pressure sensor may be the cause of your problems if the fuel pressure level reflected on the scanner does not match the actual fuel pressure. Variations in the fuel pressure regulator control voltage should reflect fluctuations in the actual fuel rail pressure. Otherwise, suspect that the fuel pressure regulator is faulty, there is an open or short circuit in one of the fuel pressure regulator control circuits, or the PCM is faulty.

To test the electronic fuel pressure regulator and individual fuel pressure regulator control circuits, use the DVOM and follow the manufacturer’s recommendations. Disconnect controllers from the circuit before testing circuit resistance and continuity with the DVOM.

Additional Diagnostic Notes:

The fuel rail and associated components are under high pressure. Be cautious when removing the fuel pressure sensor or fuel pressure regulator.
Fuel pressure tests should be performed with the ignition switch in the key on engine off (KOEO) position

P2297 – Oxygen Sensor Out of Range During Deceleration, Bank 1 Sensor 1

Possible Causes of P2297 Code

The error code P2297 is generally related to a problem with the rear heated oxygen sensor (HO2S). Here are the most common causes:

  • Exhaust leak before or near the HO2S sensor

  • Faulty rear heated oxygen sensor (HO2S)

  • Open or shorted HO2S sensor wiring

  • Poor electrical connection on the HO2S sensor circuit

What Does the P2297 Code Mean?

The P2297 code is related to a malfunction of the rear heated oxygen sensor. This sensor is essential for measuring the efficiency of the vehicle’s catalyst. During a deceleration fuel shut-off (DFSO) event, the powertrain control module (PCM) monitors the rate at which the oxygen sensor switches from rich to lean. If this transition occurs too slowly, compared to a calibrated threshold value, the PCM triggers the recording of the P2297 code.

How to Fix the P2297 Code?

Steps to Diagnose and Repair P2297:

  1. Inspect the possible causes mentioned above:

    • Check for any exhaust leaks near the rear heated oxygen sensor.

    • Examine the rear heated oxygen sensor (HO2S) for any signs of failure.

    • Check the wiring harness of the HO2S sensor for breaks, short circuits, or connection issues.

  2. Visual inspection of wiring and connectors:

    • Check the connector pins for any corrosion, physical damage, or disconnection.

    • Ensure the wiring harness is properly connected and free from any defects.

  3. Repair or replacement of faulty components:

    • If the HO2S sensor is faulty, replace it with a model compatible with your vehicle.

    • If the wiring harness or connectors are damaged, repair or replace them as needed.

Symptoms Associated with P2297 Code

Here are some common symptoms when the P2297 code is stored:

  • Check engine light on

  • Engine maintenance warning light (often with an upcoming service indication)

  • Engine performance issues: reduced fuel efficiency, driving irregularities.

Summary of P2297 Code

The P2297 code is associated with a performance issue of the rear heated oxygen sensor (HO2S), affecting the catalyst’s efficiency. This may be due to an exhaust leak, a faulty sensor, or wiring problems. To correct this issue, first inspect the exhaust system, then the sensor and wiring, and perform the necessary repairs.

Related Articles:

P2298 – O2 Sensor Out of Range During Deceleration, Bank 2 Sensor 1

P2298 Possible Causes

  • Faulty O2 sensor
  • O2 sensor harness is open or shorted
  • Poor electrical connection in O2 sensor circuit

What Does It Mean?

How to Fix Code P2298

Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

P2298 Possible Symptoms

Engine light on (or service engine soon warning light)

P2298 Meaning

O2 Sensor Out of Range During Deceleration, Bank 2 Sensor 1 is the generic description for P2298 code, but the manufacturer may have a different description. Currently, we don’t have more information about OBDII code P2298.

P2299 – Brake Pedal Position / Accelerator Pedal Position Incompatible

Meaning of Code P2299

Code P2299 indicates a signal conflict between the Accelerator Pedal Position Sensor (APPS) and the Brake Pedal Position Sensor. The PCM (Powertrain Control Module) detects that the accelerator remains partially open while the brake is applied, which is considered a hazardous situation (e.g., risk of engine runaway).

  • Normal Operation:
    When the brake is pressed, the PCM automatically reduces throttle opening to prevent engine overload.

  • Code Triggering:
    If the PCM detects a fixed or inconsistent position of the accelerator during braking, it activates limp mode (reduced power) and logs P2299.

Possible Causes

  1. Faulty APPS: Internal resistance out of specification.

  2. Failed Brake Pedal Position Sensor: Incorrect signal sent to the PCM.

  3. Wiring Issues:

    • Short circuit or open circuit in the APPS or brake harness.

    • Oxidized connectors, bent pins, or damaged wires.

  4. PCM Failure (rare).

Common Symptoms

  • 🚨 Check Engine Light On.

  • 🐌 Reduced Engine Power (Limp Home mode).

  • 🛑 Unstable Idle or stalling.

  • 🚗 Unresponsive Acceleration despite pressing the pedal.

Step-by-Step Diagnostic Procedure

1. Visual Inspection

  • Locate the Sensors:

    • APPS: Usually near the accelerator pedal.

    • Brake Sensor: Under the dashboard, near the brake pedal.

  • Check Connectors:

    • Disconnect and inspect pins for corrosion, oxidation, or damage.

    • Clean with contact spray (e.g., CRC Electrical Cleaner).

2. APPS Sensor Test

  • Resistance Measurement:

    • Disconnect the APPS connector.

    • Using a multimeter in ohmmeter mode (Ω), measure the resistance between the sensor terminals.

    • Expected Values: Varies by model (e.g., 1,500–3,000 Ω with pedal released).

    • If out of range → Replace APPS.

  • Voltage Test:

    • Reconnect the connector, turn ignition on (without starting).

    • Measure voltage between the signal terminal and ground.

    • Voltage should gradually vary from 0.5 V to 4.5 V when pressing the pedal.

3. Brake Pedal Sensor Test

  • Use a Diagnostic Tool:

    • Read the live data from the brake sensor (should change from Released to Applied).

  • Manual Test:

    • Disconnect the connector and check continuity between terminals when pressing the pedal.

4. Electrical Circuit Check

  • Inspect APPS/Brake Harness:

    • Look for cut, pinched wires, or short circuits to ground.

    • Use a multimeter in continuity mode to check each wire between the sensor and PCM.

5. PCM Update

  • Check TSBs (Technical Service Bulletins) for vehicle-specific software updates.

Repair Solutions

  1. Replace APPS or Brake Sensor if faulty (prefer OEM parts).

  2. Repair Harness:

    • Waterproof soldering + heat shrink tubing for damaged wires.

  3. Clean Connectors: Use contact spray and an anti-static brush.

  4. Reset PCM:

    • Clear P2299 code with an OBD-II tool.

    • Perform an APPS learning procedure if needed (follow service manual).

Specific Cases by Brand

  • Volkswagen/Audi: Recurrent APPS connector corrosion issues under pedals.

  • Toyota/Lexus: Brake sensor failures related to moisture (check sealing).

Important Tips

  • ⚠️ Safety: Always test the vehicle in a safe environment after repair (risk of power loss).

  • 🔧 Recommended Tools:

    • Digital multimeter.

    • Advanced diagnostic tool (e.g., Autel MaxiCOM, Launch X431).

  • 📚 Refer to the service manual for exact resistance/voltage values.

Note: If the code reappears after repair, check the throttle body wiring (possible interference).

P229A Fuel Pressure Regulator 2 Control Limit Exceeded – Pressure Too Low

How severe is this DTC?

Since insufficient/excessive fuel pressure can damage internal engine components and the catalytic converter, and lead to various driving issues, a P229A code should be classified as severe.

What are some symptoms of the code?

Symptoms of a P229A trouble code may include:

  • Engine misfire codes and idle control codes may also accompany a P229A
  • Reduced fuel efficiency
  • Delayed starting when the engine is cold
  • Black smoke from the exhaust system

What are some common causes of the code?

Causes of this code may include:

  • Engine timing is incorrect
  • Low engine oil pressure
  • Faulty fuel pressure sensor
  • Faulty fuel pressure regulator
  • Shorted or open wiring or connectors in the fuel pressure regulator control circuit
  • Incorrect PCM or PCM programming error

What are the troubleshooting steps for P229A?

You will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable source of vehicle information to accurately diagnose a P229A code.

You can save time by searching for Technical Service Bulletins (TSBs) that match the stored code, the vehicle (year, make, model, and engine), and the symptoms present. This information can be found in your vehicle information source. If you find the right TSB, it might provide a quick solution to your diagnosis.

After connecting the scanner to the vehicle’s diagnostic port and retrieving all stored codes and relevant freeze frame data, note the information (in case the code turns out to be intermittent). After that, clear the codes and test-drive the vehicle until one of two things happens; the code returns or the PCM enters readiness mode.

The code may be more difficult to diagnose if the PCM enters readiness mode at this point, as the code is intermittent. The condition that caused the P229A to be stored may need to worsen before an accurate diagnosis can be made. If the code returns, proceed with the diagnosis.

You can obtain connector face views, connector pinout charts, component location diagrams, wiring diagrams, and diagnostic flowcharts (related to the specific code and vehicle) using your vehicle information source.

Perform a visual inspection of the associated wiring and connectors. Repair or replace any wiring that is cut, burned, or damaged.

Use the DVOM to test the voltage and ground circuits at the electronic fuel regulator and fuel pressure sensors. If no voltage is detected, check the system fuses. Replace any blown or faulty fuses as needed and retest.

If voltage is detected, test the corresponding circuit at the PCM connector. If no voltage is detected there, suspect an open circuit between the sensor in question and the PCM. If voltage is found there, suspect a PCM programming error or a faulty PCM.

Test the fuel pressure regulator and fuel pressure sensor with the DVOM. If either does not meet the manufacturer’s specifications, consider it faulty.

If the fuel regulator and sensor(s) appear to be functioning correctly, use a manual pressure gauge to test the actual fuel pressure at the rail to reproduce the failure condition.

The fuel rail and associated components may be under (extremely) high pressure
Be cautious when removing the fuel pressure sensor or fuel pressure regulator
Fuel pressure tests should be performed with the ignition switch in the Key On Engine Off (KOEO) position

Fuel Pressure Regulator 2 Control Limit Exceeded – Pressure Too High

How severe is this DTC?

Since insufficient/excessive fuel pressure can damage the internal engine and catalytic converter and lead to various driving issues, a P229B code should be classified as severe.

What are some of the symptoms of the code?

Symptoms of a P229B fault code may include:

  • Engine misfire codes and idle control codes may also accompany a P229B
  • Reduced fuel efficiency
  • Delayed starting when the engine is cold
  • Black smoke from the exhaust system

What are some common causes of the code?

Causes

of this code may include:

  • The engine is not timed correctly
  • Low engine oil pressure
  • Faulty fuel pressure sensor
    Faulty fuel pressure regulator
  • Shorted or open wiring or connectors in the fuel pressure regulator control circuit
  • Incorrect PCM or PCM programming error

What are the troubleshooting steps for P229B?

You will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable source of vehicle information to accurately diagnose a P229B code.

You can save time by looking for Technical Service Bulletins (TSBs) that match the recorded code, the vehicle (year, make, model, and engine), and the symptoms presented. This information can be found in your vehicle information source. If you find the right TSB, it might provide a quick solution to your diagnosis.

After connecting the scanner to the vehicle’s diagnostic port and retrieving all stored codes and relevant freeze frame data, note the information (in case the code turns out to be intermittent). After that, clear the codes and test the vehicle until one of two things happens; the code is restored or the PCM enters readiness mode.

The code may be more difficult to diagnose if the PCM enters readiness mode at this point, as the code is intermittent. The condition that caused the P229B to be stored may need to worsen before an accurate diagnosis can be made. If the code is restored, proceed with the diagnosis.

You can obtain connector face views, connector pinout diagrams, component location diagrams, wiring diagrams, and diagnostic flowcharts (related to the code and the specific vehicle) using your vehicle information source.

Perform a visual inspection of the associated wiring and connectors. Repair or replace any wiring that is cut, burned, or damaged.

Use the DVOM to test the voltage and ground circuits at the electronic fuel regulator (2) and fuel pressure sensors. If no voltage is detected, check the system fuses. Replace any blown or faulty fuses as needed and retest.

If voltage is detected, test the corresponding circuit at the PCM connector. If no voltage is detected there, suspect an open circuit between the sensor in question and the PCM. If voltage is found there, suspect a PCM programming error or faulty PCM.

Test the fuel pressure regulator and fuel pressure sensor with the DVOM. If either does not meet the manufacturer’s specifications, consider it faulty.

If the fuel regulator (2) and sensor(s) appear to be functioning correctly, use a manual pressure gauge to test the actual fuel pressure on the rail to replicate the failure condition.

  • The fuel rail and associated components may be under (extremely) high pressure
  • Be cautious when removing the fuel pressure sensor or fuel pressure regulator
  • Fuel pressure tests should be performed with the ignition switch in the Key On Engine Off (KOEO) position

P229C Fuel Pressure Regulator 2 Learning Limit Exceeded – Too Low

How severe is this DTC?

Since insufficient/excessive fuel pressure can damage the internal engine and catalytic converter and lead to various driving issues, a P229C code should be classified as severe.

What are some of the symptoms of the code?

Symptoms of a P229C fault code may include:

  • No start condition
  • Engine misfire codes and idle control codes may also accompany a P229C
  • Reduced fuel efficiency
  • Delayed starting when the engine is cold
  • Black smoke from the exhaust system

What are some common causes of the code?

Causes of this code may include:

  • Engine timing is incorrect
  • Low engine oil pressure
  • Faulty fuel pressure sensor
  • Faulty fuel pressure regulator
  • Shorted or open wiring or connectors in the fuel pressure regulator control circuit
  • Incorrect PCM or PCM programming error

What are the troubleshooting steps for P229C?

You will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable source of vehicle information to accurately diagnose a P229C code.

You can save time by looking for Technical Service Bulletins (TSBs) that match the recorded code, the vehicle (year, make, model, and engine), and the symptoms presented. This information can be found in your vehicle information source. If you find the right TSB, it might provide a quick solution to your diagnosis.

After connecting the scanner to the vehicle’s diagnostic port and retrieving all stored codes and relevant freeze frame data, note the information (in case the code turns out to be intermittent). After that, clear the codes and test the vehicle until one of two things happens; the code is restored or the PCM enters readiness mode.

The code may be more difficult to diagnose if the PCM enters readiness mode at this point, as the code is intermittent. The condition that caused the P229C to be stored may need to worsen before an accurate diagnosis can be made. If the code is restored, proceed with the diagnosis.

You can obtain connector face views, connector pinout charts, component location diagrams, wiring diagrams, and diagnostic flowcharts (related to the code and the specific vehicle) using your vehicle information source.

Perform a visual inspection of the associated wiring and connectors. Repair or replace any wiring that is cut, burned, or damaged.

Use the DVOM to test the voltage and ground circuits at the electronic fuel regulator and fuel pressure sensors. If no voltage is detected, check the system fuses. Replace any blown or faulty fuses as needed and retest.

If voltage is detected, test the corresponding circuit at the PCM connector. If no voltage is detected there, suspect an open circuit between the sensor in question and the PCM. If voltage is found there, suspect a PCM programming error or faulty PCM.

Test the fuel pressure regulator and fuel pressure sensor with the DVOM. If either does not meet the manufacturer’s specifications, consider it faulty.

If the fuel regulator and sensor(s) appear to be functioning correctly, use a manual pressure gauge to test the actual fuel pressure on the rail to replicate the failure condition.

  • The fuel rail and associated components may be under (extremely) high pressure
  • Be cautious when removing the fuel pressure sensor or fuel pressure regulator
  • Fuel pressure tests should be performed with the ignition switch in the Key On Engine Off (KOEO) position

P229D Fuel Pressure Regulator 2 Control Limit Exceeded – Too High

How severe is this DTC?

Since insufficient/excessive fuel pressure can damage the internal engine and catalytic converter and lead to various driving issues, a P229D code should be classified as severe.

What are some of the symptoms of the code?

Symptoms of a P229D fault code may include:

  • No start condition
  • Engine misfire codes and idle control codes may also accompany a P229D
  • Reduced fuel efficiency
  • Delayed starting when the engine is cold
  • Black smoke from the exhaust system

What are some common causes of the code?

Causes of this code may include:

  • Engine timing is incorrect
  • Low engine oil level/pressure
  • Faulty fuel pressure sensor
  • Faulty fuel pressure regulator
  • Shorted or open wiring or connectors in the fuel pressure regulator control circuit
  • Incorrect PCM or PCM programming error

What are the troubleshooting steps for P229D?

You will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable source of vehicle information to accurately diagnose a P229D code.

You can save time by looking for Technical Service Bulletins (TSBs) that match the recorded code, the vehicle (year, make, model, and engine), and the symptoms presented. This information can be found in your vehicle information source. If you find the right TSB, it might provide a quick solution to your diagnosis.

After connecting the scanner to the vehicle’s diagnostic port and retrieving all stored codes and relevant freeze frame data, note the information (in case the code turns out to be intermittent). After that, clear the codes and test the vehicle until one of two things happens; the code is restored or the PCM enters readiness mode.

The code may be more difficult to diagnose if the PCM enters readiness mode at this point, as the code is intermittent. The condition that caused the P229D to be stored may need to worsen before an accurate diagnosis can be made. If the code is restored, proceed with the diagnosis.

You can obtain connector face views, connector pinout charts, component location diagrams, wiring diagrams, and diagnostic flowcharts (related to the code and the specific vehicle) using your vehicle information source.

Perform a visual inspection of the associated wiring and connectors. Repair or replace any wiring that is cut, burned, or damaged.

Use the DVOM to test the voltage and ground circuits at the electronic fuel regulator (2) and fuel pressure sensors. If no voltage is detected, check the system fuses. Replace any blown or faulty fuses as needed and retest.

If voltage is detected, test the corresponding circuit at the PCM connector. If no voltage is detected there, suspect an open circuit between the sensor in question and the PCM. If voltage is found there, suspect a PCM programming error or faulty PCM.

Test the fuel pressure regulator and fuel pressure sensor with the DVOM. If either does not meet the manufacturer’s specifications, consider it faulty.

If the fuel regulator (2) and sensor(s) appear to be functioning correctly, use a manual pressure gauge to test the actual fuel pressure on the rail to replicate the failure condition.

  • The fuel rail and associated components may be under (extremely) high pressure
  • Be cautious when removing the fuel pressure sensor or fuel pressure regulator
  • Fuel pressure tests should be performed with the ignition switch in the Key On Engine Off (KOEO) position