P2171 Possible Causes

• Faulty exhaust pressure regulator vent solenoid
• Exhaust pressure regulator vent solenoid harness is open or shorted
• Poor electrical connection in exhaust pressure regulator solenoid circuit

What Does It Mean?

How to Fix Code P2171

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.

P2171 Possible Symptoms

Engine light on (or service engine soon warning light)

P2171 Meaning

Exhaust pressure regulator vent solenoid control circuit is the generic description for code P2171, but the manufacturer may have a different description

Code Severity and Symptoms

The severity of this code can range from moderate to severe depending on the specific malfunction. Symptoms of a P2172 trouble code may include:

• Illumination of the Malfunction Indicator Light (MIL)
• Engine may not start
• Poor or sluggish acceleration response
• Automatic transmission will not shift
• Additional codes may be stored

Common Causes of This DTC Code

Potential causes of the P2172 throttle actuator code may include:

• Vacuum leaks (most likely)
• Faulty Manifold Absolute Pressure sensor
• Abnormal system voltages

P2172 Diagnostic and Repair Procedures

The first step in troubleshooting any malfunction is to check for Technical Service Bulletins (TSBs) for the specific vehicle by year, model, and powertrain. In some circumstances, this can save significant time by pointing you in the right direction.

For example, we’re aware of a bulletin that applies to 2013-2015 Dodge Dart and Chrysler 200 vehicles, bulletin number 18-006-15, which addresses this DTC and others, with the fix being to reprogram the PCM.

The second step for this code is to perform a PCM scan to identify other trouble codes. This code is an informational code and in most cases functions to alert the driver that the PCM has initiated a fail-safe mode due to a malfunction or failure in a system not directly related to the throttle actuator.

If other codes are identified, you should check for TSBs related to the specific vehicle and those codes. If no TSB has been issued, you should follow the specific troubleshooting steps for those codes to identify the source of the malfunction that the PCM is detecting to put the engine in fail-safe or limp mode.

Once all other codes have been cleared, or if no other codes are detected, if the throttle actuator code persists, both the PCM and throttle actuator should be evaluated. All wiring and connections should be visually inspected for obvious defects as a starting point. Also check the MAP sensor circuit.

Common Mistake

Replacing the throttle actuator or PCM when other malfunctions are setting this code.

Rare Repair

Replacing the throttle actuator assembly

I hope the information in this article has been helpful in guiding you in the right direction to resolve the issue with your throttle actuator control system force code. This article is strictly informational, and specific technical data and service bulletins for your vehicle should always take priority.

Fault Code Severity and Symptoms

The severity of this code can range from moderate to severe depending on the specific malfunction. Symptoms of a P2173 fault code may include:

• Malfunction Indicator Light (MIL) or ABS warning light
• Engine may not start
• No or poor acceleration response
• Automatic transmission won’t shift
• Additional codes may be stored

Common Causes of This DTC

Potential causes of throttle motor code P2173 may include:

• Engine overheating
• Vacuum leaks (particularly on Dodge/Chrysler/Jeep vehicles)
• Manifold Absolute Pressure sensor malfunction
• Abnormal system voltages

P2173 Diagnostic and Repair Procedures

The first step in troubleshooting any malfunction is to search for Technical Service Bulletins (TSBs) for the specific vehicle by year, model, and powertrain. In some circumstances, this can save significant time by pointing you in the right direction.

For example, we’re aware of a bulletin that applies to certain 2007-2008 Dodge and Jeep vehicles (Compass, Patriot, Caliber), bulletin number 18-019-08, which involves this DTC and others, where the fix involves reprogramming the PCM.

The second step for this code is to perform a PCM scan to identify other fault codes. This code is an informational code and in most cases serves to alert the driver that the PCM has initiated a fail-safe mode due to a malfunction or failure in a system not directly related to the throttle actuator control.

If other codes are identified, you should check for TSBs related to the specific vehicle and those codes. If no TSB has been issued, you should follow the specific troubleshooting steps for those codes to identify the source of the malfunction that the PCM is detecting to put the engine in fail-safe or limp mode.

Once all other codes have been cleared, or if no other codes are detected, if the throttle actuator control code persists, both the PCM and throttle actuator should be evaluated. All wiring and connections should be visually inspected for obvious defects as a starting point.

Common Mistake

Replacing the throttle actuator or PCM when other malfunctions are setting this code.

Rare Repair

Replacing the throttle actuator control

I hope the information in this article has been helpful in guiding you in the right direction to resolve the issue with your throttle actuator control system force code. This article is strictly informational, and specific technical data and service bulletins for your vehicle should always take priority.

Fault Code Severity and Symptoms

The severity of this code can range from moderate to severe depending on the specific malfunction. Symptoms of a P2174 fault code may include:

• Malfunction Indicator Lamp (MIL) or ABS warning light
• Engine may not start
• Poor or weak acceleration response
• Automatic transmission won’t shift
• Additional codes may be stored

Common Causes of This DTC Code

Potential causes of throttle actuator P2174 engine code may include:

• Engine overheating
• Manifold Absolute Pressure sensor malfunction
• Abnormal system voltages

P2174 Diagnostic and Repair Procedures

The first step in troubleshooting any malfunction is to search for Technical Service Bulletins (TSBs) for your specific vehicle by year, model, and powertrain. In some circumstances, this can save significant time by pointing you in the right direction.

The second step for this code is to perform a PCM scan to identify other fault codes. This code is an informational code and in most cases serves to alert the driver that the PCM has initiated a fail-safe mode due to a malfunction or failure in a system not directly related to the throttle actuator.

If other codes are identified, you should check TSBs related to your specific vehicle and those codes. If no TSB has been issued, you should follow the specific troubleshooting steps for those codes to identify the source of the malfunction that the PCM is detecting to put the engine in fail-safe or limp mode.

Once all other codes have been cleared or if no other codes are detected, if the throttle actuator code persists, both the PCM and throttle actuator should be evaluated. All wiring and connections should be visually inspected for obvious defects as a starting point.

Common Mistake

Replacing the throttle actuator or PCM when other malfunctions are setting this code.

Rare Repair

Replacing the throttle actuator control

I hope the information in this article has been helpful in guiding you in the right direction to resolve the issue with your throttle actuator control system force code. This article is strictly informational, and specific technical data and service bulletins for your vehicle should always take priority.

Fault Code Severity and Symptoms

The severity of this code can range from moderate to severe depending on the specific malfunction. Symptoms of a P2175 fault code may include:

• Malfunction Indicator Lamp (MIL) or ABS warning light
• Engine may not start
• Poor or weak acceleration response
• Automatic transmission will not shift
• Additional codes may be stored

Common Causes of This DTC Code

Potential causes

of throttle actuator P2175 engine code may include:

• Engine overheating
• Manifold Absolute Pressure sensor malfunction
• Abnormal system voltages

P2175 Diagnostic and Repair Procedures

The first step in troubleshooting any malfunction is to search for Technical Service Bulletins (TSBs) for the specific vehicle by year, model, and powertrain. In some circumstances, this can save significant time by pointing you in the right direction.

The second step for this code is to perform a PCM scan to identify other fault codes. This code is an informational code and in most cases serves to alert the driver that the PCM has initiated a fail-safe mode due to a malfunction or failure in a system not directly related to the throttle actuator.

If other codes are identified, you should check TSBs related to the specific vehicle and those codes. If no TSB has been issued, you should follow the specific troubleshooting steps for those codes to identify the source of the malfunction that the PCM is detecting to put the engine in fail-safe or limp mode.

Once all other codes have been cleared or if no other codes are detected, if the throttle actuator code persists, both the PCM and throttle actuator should be evaluated. All wiring and connections should be visually inspected for obvious defects as a starting point.

Common Mistake

Replacing the throttle actuator or PCM when other malfunctions are setting this code.

Rare Repair

Replacing the throttle actuator control

I hope the information in this article has been helpful in guiding you in the right direction to resolve the issue with your throttle actuator system force code. This article is strictly informational and specific technical data and service bulletins for your vehicle should always take priority.

Fault Code Severity and Symptoms

The severity of this code can range from moderate to severe depending on the specific malfunction. Symptoms of a P2176 fault code may include:

• Engine fails to start
• Little or no throttle response
• Check engine light illuminated
• ABS light illuminated
• Automatic transmission won’t shift
• Additional codes present

What are the common repairs?

• Replacement or cleaning of throttle actuator motor
• Cleaning connector corrosion
• Repairing or replacing wiring
• Flashing or replacing PCM

Diagnostic and Repair Procedures

The first step in troubleshooting any malfunction is to search for Technical Service Bulletins (TSBs) for the specific vehicle by year, model, and powertrain. In some circumstances, this can save significant time in the long run by pointing you in the right direction.

The second step for this code is to perform a PCM scan to identify other fault codes. This code is an informational code and in most cases functions to alert the driver that the PCM has initiated a fail-safe mode due to a malfunction or failure in a system not directly related to the throttle actuator.

If other codes are identified, you should check TSBs related to the specific vehicle and that code. If no TSB has been issued, you should follow the specific troubleshooting steps for that code to identify the source of the malfunction that the PCM is detecting to put the engine in fail-safe or limp mode.

Once all other codes have been cleared or if no other codes are detected, if the throttle actuator code still exists, both the PCM and throttle actuator need to be evaluated. All wiring and connections should be visually inspected for obvious defects as a starting point.

A strong possibility for this code is that the idle calibration procedure needs to be reapplied to the vehicle using an advanced scan tool.

Common Mistake

Replacing the throttle actuator or PCM when other malfunctions are setting this code.

Rare Repair

Replacing the throttle actuator control

I hope the information in this article has been helpful in pointing you in the right direction to fix the issue with your throttle actuator system force code. This article is strictly informational and specific vehicle technical data and service bulletins should always take priority.

Symptoms

Symptoms of a P2177 engine code may include:

• Malfunction Indicator Lamp (MIL) illuminated
• Lack of power
• Occasional misfires
• Poor fuel economy

Possible causes for this code definition are:

• Faulty Air/Fuel Ratio sensor / Oxygen sensor (AFR/O2)
• Faulty Mass Air Flow sensor (MAF)
• Rarely – Faulty Powertrain Control Module (PCM)

Diagnostic and Repair Procedures

A good starting point is always to check the Technical Service Bulletins (TSBs) for your specific vehicle. Your issue might be a known problem with a published fix from the manufacturer and could save you time and money during diagnosis.

First, note if there are any other Diagnostic Trouble Codes. If any are related to the fuel/fuel system, diagnose those first. Misdiagnosis is known to occur if a technician diagnoses this code before codes related to the fuel system have been thoroughly diagnosed and dismissed. Ensure there are no intake or exhaust leaks. An intake leak, or vacuum leak, causes the engine to idle roughly. An exhaust leak makes the engine appear to be running lean to the AFR/O2 sensor.

Once located, visually inspect the connectors and wiring. Look for chafing, rubbing, bare wires, burns, or melted plastic. Separate the connectors and carefully inspect the terminals (the metal parts) inside the connectors. See if they look corroded, burnt, or perhaps greenish compared to the normal metallic color you are probably used to seeing. You can get electrical contact cleaner at any auto parts store if terminal cleaning is needed. If that’s not possible, find 91% isopropyl alcohol and a soft plastic-bristled brush to clean them. Then, let them air dry, get some dielectric silicone compound (the same kind used for bulb sockets and spark plug wires), and apply a small amount where the terminals make contact.

If you have a scan tool, clear the Diagnostic Trouble Codes from the memory and see if this code returns. If it does not, the connections were likely your problem.

If the code returns, we will need to test the voltage signal from the MAF sensor to the PCM. Monitor the MAF sensor voltage on your scan tool. If a scan tool is not available, test the signal from the MAF sensor with a Digital Volt Ohm Meter (DVOM). With the sensor connected, the red lead of the voltmeter should be attached to the MAF sensor signal wire and the black voltmeter lead connected to ground. Start the engine and monitor the MAF sensor input. As the engine RPM increases, the MAF sensor signal should increase. Check the manufacturer’s specifications, as there may be a chart informing you of the voltage at a given RPM. If it fails this test, replace the MAF sensor and retest.

If the previous tests passed and the code is still present, monitor the Air/Fuel Ratio sensor / Oxygen sensor (AFR/O2). If it continuously indicates the engine is running lean, locate all possibilities that could cause a lean running engine. These include:

• Intake or exhaust leaks
• Fuel system, including fuel pressure regulator / fuel pressure.
• Fuel pressure sensor
• Fuel injectors
• Post-catalytic converter O2 sensor
• EVAP system, to include the canister purge regulation valve.
• If the AFR/O2 sensor indicates the engine is running normally or even rich, a PCM may be suspected once all other issues have been ruled out.

Again, it cannot be overemphasized that all other codes must be diagnosed before this one, as problems causing other codes to set can also cause this one.

Symptoms

Symptoms of a P2178 engine code may include:

• Malfunction Indicator Lamp (MIL) illuminated
• Lack of power
• Occasional misfires
• Poor fuel economy

Causes

Possible causes for this code definition include:

• Faulty Air/Fuel Ratio Sensor or Oxygen Sensor (AFR/O2)
• Faulty Mass Air Flow (MAF) Sensor
• Rarely – Faulty Powertrain Control Module (PCM)

Diagnostic and Repair Procedures

A good starting point is always to check the Technical Service Bulletins (TSBs) for your specific vehicle. Your issue might be a known problem with a published fix from the manufacturer, which can save you time and money during diagnosis.

First, note if there are any other Diagnostic Trouble Codes. If any are related to the fuel system, diagnose those first. Misdiagnosis is known to occur if this code is diagnosed before related fuel system codes have been thoroughly diagnosed and dismissed.

Once located, visually inspect the connectors and wiring. Look for chafing, rubbing, bare wires, burns, or melted plastic. Disconnect the connectors and carefully inspect the terminals (the metal parts) inside. Check if they appear corroded, burnt, or possibly greenish compared to the normal metallic color you’re used to seeing. You can get electrical contact cleaner at any auto parts store if terminal cleaning is needed. If that’s not possible, find 91% rubbing alcohol and a soft plastic-bristled brush to use. Then, let them air dry, get some dielectric silicone compound (the same used for bulb sockets and spark plug wires), and apply it where the terminals make contact.

If you have a scan tool, clear the diagnostic codes from memory and see if this code returns. If it doesn’t, the connections were likely your issue.

If the code returns, we’ll need to test the voltage signal from the MAF sensor to the PCM. Monitor the MAF sensor voltage on your scan tool. If a scan tool isn’t available, test the signal from the MAF sensor with a Digital Volt-Ohm Meter (DVOM). With the sensor connected, attach the voltmeter’s red lead to the MAF sensor’s signal wire and the black lead to ground. Start the engine and monitor the MAF sensor input. As engine RPM increases, the MAF sensor signal should increase. Check the manufacturer’s specifications, as there may be a chart indicating the voltage at a given RPM. If it fails this test, replace the MAF sensor and retest.

If the previous tests passed and the code is still present, monitor the Air/Fuel Ratio Sensor or Oxygen Sensor (AFR/O2). If it continuously indicates the engine is running rich, locate all possibilities that could cause a rich-running engine. These include:

• Fuel system, including fuel pressure regulator/fuel pressure.
• Fuel pressure sensor
• Fuel injectors
• Post-catalytic converter O2 sensor
• EVAP system, including the canister purge control valve.
• If the AFR/O2 sensor indicates the engine is running normally or even lean, a PCM may be suspected once all other issues have been ruled out.

Again, it cannot be overemphasized that all other codes should be diagnosed before this one, as issues causing other codes to set can also trigger this one.

Symptoms

Symptoms of a P2179 engine code may include:

• Malfunction Indicator Light (MIL) illuminated
• Lack of power
• Occasional misfires
• Poor fuel economy

Causes

Possible causes for this code definition include:

• Faulty Air/Fuel Ratio Sensor/Oxygen Sensor (AFR/O2)
• Faulty Mass Air Flow (MAF) Sensor
• Rarely – Faulty Powertrain Control Module (PCM)

Diagnostic and Repair Procedures

A good starting point is always to check the Technical Service Bulletins (TSBs) for your specific vehicle. Your issue might be a known problem with a known fix published by the manufacturer and could save you time and money during diagnosis.

First, note if there are any other diagnostic trouble codes. If any are related to the fuel/fuel system, diagnose those first. Misdiagnosis is known to occur if a technician diagnoses this code before codes related to the fuel system have been thoroughly diagnosed and dismissed. Ensure there are no intake or exhaust leaks. An intake leak, or vacuum leak, causes the engine to idle roughly. An exhaust leak makes the engine appear to be running lean to the AFR/O2 sensor.

Once located, visually inspect the connectors and wiring. Look for chafing, rubbing, bare wires, burns, or melted plastic. Disconnect the connectors and carefully inspect the terminals (the metal parts) inside the connectors. Check if they appear corroded, burnt, or possibly greenish compared to the normal metallic color you are used to seeing. You can get electrical contact cleaner at any auto parts store if terminal cleaning is needed. If that’s not possible, find 91% isopropyl alcohol and a soft plastic-bristled brush to clean them. Then, let them air dry, get some dielectric silicone compound (the same kind used for bulb sockets and spark plug wires), and apply a small amount where the terminals make contact.

If you have a scan tool, clear the diagnostic codes from memory and see if this code returns. If it does not, the connections were likely your problem.

If the code returns, we will need to test the voltage signal from the MAF sensor to the PCM. Monitor the MAF sensor voltage on your scan tool. If a scan tool is not available, test the signal from the MAF sensor with a digital voltmeter (DVOM). With the sensor connected, the red lead of the voltmeter should be attached to the MAF sensor signal wire and the black lead of the voltmeter connected to ground. Start the engine and monitor the MAF sensor input. As engine RPM increases, the MAF sensor signal should increase. Check the manufacturer’s specifications, as there may be a chart indicating the voltage at a given RPM. If it fails this test, replace the MAF sensor and retest.

If the previous tests passed and the code is still present, monitor the Air/Fuel Ratio Sensor/Oxygen Sensor (AFR/O2). If it continuously indicates the engine is running lean, locate all possibilities that could cause a lean running engine. These include:

• Intake or exhaust leaks
• Fuel system, including fuel pressure regulator/fuel pressure
• Fuel pressure sensor
• Fuel injectors
• Post-catalytic converter O2 sensor
• EVAP system, including the purge control valve
• If the Bank 2 AFR/O2 sensor indicates the engine is running normally or even rich, a PCM may be suspected once all other issues have been ruled out.

Again, it cannot be overemphasized that all other codes should be diagnosed before this one, as issues causing other codes to set can also cause this one.

How severe is this DTC?

I would say rather severe. In the field, we call a lack of fuel in the burned mixture a “lean” condition. When your engine is idling, you risk causing extreme damage to the engine in the short and long term. With this in mind, always follow your engine maintenance. There must be some diligence here, so let’s keep our engines running smoothly and efficiently. After all, they pull our weight to transport us daily.

What are some of the symptoms of the code?

Symptoms of a P217A fault code may include:

• Irregular engine performance
• Misfire
• Reduced fuel economy
• Irregular idle
• Excessive smoke
• Engine noise(s)
• Lack of power
• Unable to climb steep hills
• Reduced throttle response

What are some common causes of the code?

Causes of this P217A fuel injector group supply voltage code may include:

• Faulty or damaged fuel injector(s)
• Damaged wiring harness
• Internal wiring malfunction
• Internal ECM problem
• Connector issue

What are the troubleshooting steps for P217A?

Basic Step #1

The first recommended step is to locate the “group” of sensors that the manufacturer refers to. With this information, you can then find the physical location of the injector(s) and their circuits. This may involve removing many covers and/or engine components to visually access (if possible). Be sure to inspect the wiring harness for broken wires. Any worn insulation should be properly repaired with a shrink tube to avoid further and/or future issues.

Basic Step #2

Sometimes water and/or fluids can be “trapped” in the valleys where the injectors are installed. This increases the chances of the sensor connectors, among other electrical connections, corroding at a faster rate than normal. Ensure everything is as expected and that the connector tabs seal the connection properly. Feel free to use an electrical contact cleaner to make everything connect and disconnect smoothly, not to mention the increased electrical connectivity in the connections with the use of this product.

Basic Step #3

Check the circuit integrity by following the troubleshooting steps provided by your specific vehicle’s maintenance manual. An example is to disconnect the supply voltage circuit from the ECM and the fuel injector, then using your multimeter, determine whether the wires are in good working condition or not.

A test I like to do to quickly determine if there is an open in a particular wire that would help with the P217A code is to perform a “continuity test.” Set your multimeter to RESISTANCE (aka ohm, impedance, etc.), touch one end to one end of the circuit and the other end to the other end. Any value higher than desired may indicate a problem in the circuit. Any issue here will need to be determined by tracing the particular wire you are diagnosing.