Symptoms

Symptoms of a DTC P2003 may include:

Decreased fuel economy occurs when the engine management system attempts to increase exhaust gas temperature to burn excess soot in the DPF.
The check engine light will illuminate with code “P2003”. The light may stay on or flash intermittently during DPF regeneration. The engine will be sluggish during acceleration.
Engine oil will show dilution from the ECU’s attempts to raise engine temperature. Some vehicles slightly advance fuel injection timing after top dead center to post-combust a small amount of fuel to increase exhaust temperatures. Some of this fuel enters the crankcase. When the ECU determines DPF regeneration is needed, oil life is significantly shortened.
If the DPF isn’t cleared, the ECU will enter “Limp Home Mode” until the situation is corrected.

Potential Causes

Causes of this DTC may include:

Excessive low-speed operation will trigger this code. Heat in the 500°C to 600°C range is required to burn soot in the DPF. Even with the engine management computer’s efforts, it struggles to generate enough heat to clean the DPF at low RPMs.

• An air leak upstream of the DPF will alter sensor readings resulting in the code
• Faulty computer strategies or components will prevent proper regeneration
• Fuel with high sulfur content quickly clogs the DPF
• Some aftermarket accessories and performance modifications
• Dirty air filter element
• Damaged DPF

Diagnostic Steps

and possible solutions

Solutions are somewhat limited since the DPF isn’t faulty, only temporarily clogged with soot particles. If the light is on and P2003 code is set, use the process of elimination starting with a visual inspection.

Inspect the DPF on bank #2 for loose connections on the engine side where it mounts to the exhaust.

Inspect the differential pressure sensors located before and after the DPF (bank 2). Look for burned wires or loose/corroded connectors. Separate connectors and check for bent or corroded pins. Ensure sensor wires aren’t resting on the DPF. Start the truck and check for leaks on or around the unit.

If everything checks out in the above steps, drive the truck for about 30 minutes at highway speed to sufficiently increase exhaust temperature for DPF regeneration. Personally, I’ve found idling the engine at 1400 RPM for about 20 minutes achieves the same results.

If the problem persists after highway driving, the best approach is to take it to a shop and connect it to a diagnostic computer like Tech II. This is inexpensive and they can monitor sensors and ECU in real time. They can see sensor signals and whether the ECU is actually attempting the regeneration process. The faulty component is quickly identified.

If you primarily do city driving and this is a recurring issue, there’s another solution. Most shops can reprogram your computer to disable the regeneration process quickly. Then remove the DPF and replace it with a straight pipe (if legal in your jurisdiction). Problem solved. Don’t discard the DPF though – it’s worth significant money if you sell it or need it in the future.

NOTE: Some modifications like cold air intake (CAI) kits or cat-back exhaust kits can trigger this code and may also affect your manufacturer’s warranty. If you have such a modification and get this code, reinstall the stock part and see if it clears the code. Or try contacting the kit manufacturer to see if this is a known issue.

Symptoms

Symptoms of a P2004 code may include:

• Reduced engine performance, especially at low RPM
• Decreased fuel efficiency
• Engine surging

Causes

Possible causes of this engine code include:

• Faulty IMRC actuator solenoid
• Loose or binding intake manifold runner controls
• Faulty intake manifold runner control position sensor
• Open or shorted wiring in the IMRC actuator solenoid control circuit
• Defective MAP sensor
• Corroded IMRC actuator solenoid connector face

Diagnostic and Repair Procedures

When attempting to diagnose a P2004 code, a diagnostic scanner, digital volt/ohmmeter (DVOM), and a reliable vehicle information source such as AllData DIY will be required.

Before beginning your diagnosis, check Technical Service Bulletins (TSBs) for the specific symptoms, stored codes, and vehicle make and model. If a related TSB is found, the information it contains may help you diagnose the P2004 in your vehicle.

I prefer to start my diagnosis with a visual inspection of the system wiring and connector faces. It appears that IMRC actuator connectors are prone to corrosion that could cause an open circuit, so pay special attention to these.

Next, I typically connect the scanner to the vehicle’s diagnostic connector and retrieve all stored codes and freeze frame data. I prefer to note this information in case it’s an intermittent code; then I would clear the codes and perform a road test to see if the code resets.

If the code resets, proceed to the IMRC actuator solenoid and IMRC runner position sensor. Consult your vehicle information source for testing recommendations for these components. Using the DVOM, perform a resistance test on both components. If the actuator or position sensor does not meet manufacturer recommendations, replace the faulty part and retest the system.

If both the actuator resistance and sensor resistance are within manufacturer specifications, use the DVOM to test resistance and continuity on all system circuits. To avoid damaging the controller, disconnect all associated controllers before testing. Repair or replace shorted or open circuits as needed.

Additional Diagnostic Notes:

Test IMRC flap binding with actuator disconnected from shaft
The screws (or rivets) that secure the flaps to the shaft may loosen or fall out, causing the flaps to bind
Carbon coking inside the intake manifold walls can cause binding

Symptoms

Symptoms of a P2005 code may include:

• Reduced engine performance, especially at low RPM
• Decreased fuel efficiency
• Engine surging

Causes

Possible causes of this engine code include:

• Faulty Bank 2 IMRC actuator solenoid
• Loose or binding intake manifold runners on Bank 2
• Faulty Bank 2 intake manifold runner position sensor
• Open or shorted wiring in the Bank 2 IMRC actuator solenoid control circuit
• Defective MAP sensor
• Corroded IMRC actuator solenoid connector face

Diagnostic and Repair Procedures

When attempting to diagnose a P2005 code, a diagnostic scanner, digital volt/ohmmeter (DVOM), and a reliable vehicle information source such as All Data DIY will be required.

Before beginning your diagnosis, check Technical Service Bulletins (TSBs) for the specific symptoms, stored codes, and vehicle make and model. If a relevant TSB is found, the information it contains may help you diagnose P2005 in your vehicle.

I like to start my diagnosis with a visual inspection of the system wiring and connector faces. It appears that IMRC actuator connectors are prone to corrosion that could cause an open circuit, so pay special attention to these.

Next, I normally connect the scanner to the vehicle’s diagnostic connector and retrieve all stored codes and freeze frame data. I prefer to note this information in case it’s an intermittent code; then I would clear the codes and perform a road test to see if the code resets.

If the code resets, proceed to the IMRC actuator solenoid and IMRC runner position sensor. Consult your vehicle information source for testing recommendations for these components. Using the DVOM, perform a resistance test on both components. If the actuator or position sensor does not meet manufacturer recommendations, replace the faulty part and retest the system.

If both the actuator resistance and sensor resistance are within manufacturer specifications, use the DVOM to test resistance and continuity on all system circuits. To avoid damaging the controller, disconnect all associated controllers before testing. Repair or replace shorted or open circuits as needed.

 

Additional Diagnostic Notes:

Test IMRC flap binding with actuator disconnected from shaft
The screws (or rivets) that secure the flaps to the shaft may loosen or fall out, causing the flaps to bind
Carbon coking inside the intake manifold walls can cause binding

Symptoms of P2006 Code

Common symptoms associated with P2006 code may include:

• Hesitation during acceleration
• Rich exhaust gas mixture
• Reduced fuel efficiency
• Engine over-revving

Possible Causes of P2006 Code

Potential causes of this engine code include:

• Loose or binding intake runners
• Faulty IMRC actuator solenoid
• Defective intake manifold runner control position sensor
• Open or shorted wiring in IMRC actuator solenoid control circuit
• Carbon buildup on IMRC flaps or intake manifold ports
• Faulty MAP sensor
• Corrosion on IMRC actuator solenoid connector face

Diagnostic and Repair Procedures

To diagnose a P2006 code, you will need a diagnostic scanner, digital voltmeter/ohmmeter (DVOM), and a reliable source of information for your vehicle. Before starting diagnosis, it’s recommended to check technical service bulletins (TSBs) for specific symptoms, stored codes, and vehicle make/model information.

Here are the general diagnostic steps:

1. Visual Inspection: Begin with a visual inspection of the system wiring and connector faces, particularly those of the IMRC actuator solenoid, which are prone to corrosion. Corrosion can cause an open circuit, so pay close attention to this area.

2. Scanner and Data Collection: Connect the diagnostic scanner to the vehicle, retrieve all stored codes and freeze frame data. Note this information, especially if the code might be intermittent. Then clear the codes and test drive the vehicle to see if the code resets.

3. Component Testing: If the code resets, check the IMRC actuator solenoid and intake manifold position sensor. Consult manufacturer specifications to test these components using the DVOM. If any components don’t meet specifications, replace them and retest.

4. Resistance and Continuity Tests: Before testing circuit resistance, disconnect all associated controllers to avoid damaging the PCM. Test resistance and continuity on all system circuits. If you find any shorted or open circuits, repair or replace them.

Additional Diagnostic Notes:

• Careful Handling: Be careful when handling small screws or rivets around intake manifold openings.
• IMRC Flap Testing: Disconnect the actuator from the shaft to test flap movement. The screws or rivets that secure the flaps to the shaft can loosen and fall out, which may cause the flaps to bind.
• Carbon Buildup: Carbon buildup inside intake manifold walls can cause IMRC flaps to bind, preventing proper operation.

Understanding OBD2 Code P1443 in MINI Vehicles

The P1443 diagnostic trouble code is a manufacturer-specific code that appears exclusively in MINI Cooper and BMW vehicles. This code indicates a problem within the Evaporative Emission Control (EVAP) system, specifically related to the leak detection pump circuit or function. When this code triggers, it means your vehicle’s onboard computer has detected an irregularity in the system designed to prevent fuel vapors from escaping into the atmosphere.

What Does P1443 Code Mean Specifically?

P1443 is defined as “Leak Detection Pump Switch Overrun” or “Evaporative Emission Control System Leak Detection Pump Sense Circuit.” The leak detection pump (LDP) is a crucial component that tests the EVAP system for leaks by creating vacuum and monitoring pressure changes. When the system detects that the LDP isn’t functioning within expected parameters, it stores the P1443 code and illuminates the check engine light.

How the EVAP System Works in MINI Coopers

The EVAP system in modern MINI vehicles is a sophisticated network designed to capture and store fuel vapors from the fuel tank rather than allowing them to escape into the atmosphere. The system includes several key components working together:

• Charcoal canister for vapor storage
• Purge valve/solenoid for vapor management
• Leak detection pump for system integrity testing
• Fuel tank pressure sensor for monitoring
• Various hoses and connectors throughout the system

Common Causes of P1443 Code in MINI Vehicles

Diagnosing the root cause of P1443 requires understanding the various components that could be malfunctioning. This code typically points to issues within the leak detection circuit or associated components.

Primary Mechanical and Electrical Causes

The most frequent causes of P1443 code activation include faulty components and system breaches:

• Defective leak detection pump (LDP) – the most common cause
• Failed or stuck open purge valve/solenoid
• Cracked or damaged EVAP system hoses
• Loose or damaged gas cap creating system leaks
• Faulty fuel tank pressure sensor providing incorrect readings
• Electrical issues in the LDP circuit including wiring problems
• Problems with the charcoal canister or vent valve

MINI-Specific Component Failures

MINI Coopers have certain components that are particularly prone to failure in specific model years. The leak detection pump in earlier MINI models (2002-2006) frequently fails due to internal diaphragm wear. Additionally, the plastic EVAP lines running underneath the vehicle are vulnerable to damage from road debris and corrosion.

Diagnostic Procedure for P1443 Code

Proper diagnosis requires a systematic approach to identify the exact cause of the P1443 code. Following a structured diagnostic process can save significant time and prevent unnecessary part replacements.

Initial Inspection and Basic Checks

Begin with these fundamental checks before proceeding to more advanced diagnostics:

• Verify the code with an OBD2 scanner and check for additional codes
• Inspect the gas cap for proper sealing and tightness
• Visually examine all accessible EVAP hoses for cracks, disconnections, or damage
• Check the leak detection pump and purge valve electrical connectors for corrosion
• Listen for unusual hissing sounds around the fuel tank area indicating vacuum leaks

Advanced Diagnostic Testing Methods

For persistent P1443 codes, more sophisticated testing is required:

• Perform smoke testing to identify vacuum leaks in the EVAP system
• Test the leak detection pump function using a professional scan tool
• Check purge valve operation through actuation tests
• Monitor fuel tank pressure sensor data in real-time
• Perform electrical tests on the LDP circuit including voltage and resistance checks

Using Specialized Diagnostic Equipment

Professional-grade diagnostic tools are essential for accurate P1443 diagnosis. BMW/MINI specific scan tools can access manufacturer-specific parameters and perform component actuation tests that generic OBD2 scanners cannot. These tools allow technicians to monitor the leak detection pump in real-time and verify its operation during diagnostic tests.

Repair Solutions and Prevention Strategies

Once the root cause is identified, appropriate repairs can restore proper EVAP system function and eliminate the P1443 code.

Component Replacement Procedures

Common repair procedures for resolving P1443 include:

• Replacing the leak detection pump – typically requires removing the rear wheel and inner fender liner
• Installing new purge valves – usually located in the engine bay near the intake manifold
• Repairing or replacing damaged EVAP hoses throughout the system
• Replacing the fuel tank pressure sensor if providing faulty readings
• Addressing any electrical issues in the wiring harness or connectors

Post-Repair Verification and System Reset

After completing repairs, proper verification is crucial to ensure the P1443 code doesn’t return:

• Clear all codes using your diagnostic scanner
• Perform a complete drive cycle to allow the system to retest
• Monitor for code recurrence over several drive cycles
• Verify the EVAP system readiness monitors set to “ready” status
• Confirm there are no pending codes in the system memory

Preventive Maintenance Recommendations

Regular maintenance can help prevent P1443 and other EVAP system codes:

• Always tighten the gas cap properly after refueling
• Replace the gas cap every 4-5 years or if damage is suspected
• During oil changes, visually inspect accessible EVAP components
• Address any fuel smell issues immediately rather than ignoring them
• Have the EVAP system professionally smoke tested during major services

Technical Considerations for Specific MINI Models

The P1443 code may present differently across various MINI Cooper generations and engine types. Understanding these nuances is essential for accurate diagnosis.

First Generation MINI Cooper (R50/R53)

In first-generation MINI Coopers, the leak detection pump is particularly prone to failure. These vehicles use a mechanical LDP that can develop internal leaks over time. Additionally, the EVAP lines running underneath the vehicle are vulnerable to damage from road debris.

Second Generation MINI Cooper (R56) and Later

Later MINI models feature updated EVAP system designs with electronic leak detection. While generally more reliable, these systems can still experience purge valve failures and electrical connection issues. The diagnostic approach for these vehicles often requires more sophisticated scanning capabilities.

Successfully diagnosing and repairing P1443 requires understanding the specific EVAP system design for your MINI model year. While some repairs are straightforward, others may require professional expertise, particularly when dealing with electronic components or complex vacuum system diagnostics. Always begin with the simplest potential causes before progressing to more complex diagnostic procedures.

Symptoms

Symptoms of a P2007 code may include:

• Hesitation during acceleration
• Rich exhaust
• Reduced fuel efficiency
• Engine surging

Causes

Causes

Possible causes of this engine code include:

• Loose or binding intake manifold runner controls, bank 2
• Faulty IMRC actuator solenoid, bank 2
• Faulty intake manifold runner position sensor, bank 2
• Open or shorted wiring in the IMRC actuator solenoid control circuit
• Carbon buildup on IMRC flaps or intake manifold ports
• Faulty MAP sensor
• Corroded IMRC actuator solenoid connector face

Diagnostic and Repair Procedures

A diagnostic scanner, digital volt/ohmmeter (DVOM), and a reliable source of vehicle information will be needed when attempting to diagnose a P2007 code. I would check technical service bulletins (TSBs) for specific symptoms, stored codes, and the vehicle’s make and model before starting my diagnosis. If I find a related TSB, the information will often help diagnose the code in question.

My usual starting point (for any diagnosis) is a visual inspection of the system wiring and connector faces. In this case, I know that IMRC actuator connectors are prone to corrosion. This could cause an open circuit, so I would focus attention on that area.

Now, I connect the scanner to the vehicle’s diagnostic connector and retrieve all stored codes and freeze frame data. I make a habit of writing down this information in case it’s an intermittent code; then I clear the codes and test drive the vehicle to see if the code resets.

Continuing, I would access the IMRC actuator solenoid and IMRC runner position sensor if the code resets. Consult your vehicle information source for testing specifications for both components. Use the DVOM to perform a resistance test on the solenoid and sensor. If either part does not meet specifications, replace it and retest the system.

Disconnect all associated controllers before testing circuit resistance with the DVOM to avoid damaging the PCM. If the actuator and sensor resistance meet manufacturer specifications, use the DVOM to test resistance and continuity on all system circuits. Repair or replace shorted or open circuits as needed.

Additional Diagnostic Notes:

Be careful when handling small screws or rivets in or near intake manifold openings
Test IMRC flap binding with the actuator disconnected from the shaft
Screws (or rivets) that secure the flaps to the shaft may loosen or fall out, causing the flaps to bind
Carbon coking inside intake manifold walls can cause IMRC flaps to bind

Symptoms Symptoms of a P2008 DTC may include:

• The engine may have a rougher idle than normal
• Sometimes the engine may tend to surge
• There may be a slight reduction in low-end torque

The fault code P2008 will be displayed
This is a “soft” code, meaning the check engine light may only flash when the ECM detects the fault. If the fault corrects itself, the light turns off. Hard codes will remain once observed until cleared.

Potential Causes Causes of this DTC may include:

Over the years, I’ve found that the intake manifold runner control solenoid is largely the issue. They are almost always located where they are exposed to heat and dirt that clogs the filter and causes them to fail. Secondly, the swirl flaps themselves get coated with soot from the EGR valve and lock in their current position.
The MAF sensor or EGR have the potential to set this code if they fail, however, they will set their own code to coincide with the P2008 code. In that case, they would be diagnosed and repaired first and the codes cleared

• The intake manifold runner control solenoid
• The swirl flaps are contaminated
• Cracked vacuum lines
• Poor electrical connection
• Open or short circuit in the wiring harness

Diagnosis and Repair

A vehicle service manual and a scan tool will be needed to diagnose and perform a conclusive repair. The ECM uses pulse width modulation to vary the position of the swirl flaps with the intake runner solenoid.

Check the vacuum hoses and ensure there are no cracks and they are properly seated.
Inspect the electrical connector of the solenoid. Look for corrosion or a loose connection.
Disconnect the solenoid connector and plug the scan tool into the solenoid connector.
Access the VSV operational check. Turn the key. Operate the solenoid with the scanner by making it open and close. If it does not respond, replace the valve.
If the valve operates but struggles to move the actuator rod, replace the intake manifold.
If the solenoid does not operate, disconnect the electrical connector. Look in the main fuse box and pull the EFI relay. Using an ohmmeter, check for continuity between the EFI terminals and the solenoid terminals on the harness side.
Consult the service manual and locate the ground terminal on the solenoid harness connector and test it for ground.
Note: Also be sure to check for TSBs, as there is a known TSB for certain Audi vehicles where the fix is to reprogram the ECM.

Introduction

Error code P2009 is an OBD-II diagnostic code indicating a problem with the intake manifold runner control (IMRC) circuit for engine bank 1. This malfunction is typically caused by lower than normal voltage detected in the control circuit.

Possible Causes

Code P2009 can be caused by several factors, including:

• A faulty intake manifold control solenoid
• Damaged or shorted wiring harness
• Corroded or poorly connected connector
• A faulty engine control module (ECU)

Symptoms

Symptoms associated with code P2009 include:

• Engine power loss
• Irregular acceleration
• Unstable idle
• Illuminated check engine light

Diagnosis and Repair

1. Visual inspection: Check connectors and wiring harness for possible damage.
2. Solenoid test: Use a multimeter to measure IMRC solenoid resistance. Values outside manufacturer specifications indicate a problem.
3. Electrical circuit check: Test circuit voltage to ensure proper power supply.
4. Replacement of faulty components: If necessary, replace the solenoid, repair wiring, or replace ECU if no other solution resolves the issue.

Conclusion

Code P2009 indicates a problem with the intake manifold control system, which can lead to engine performance issues. Proper inspection and diagnosis help identify and correct the underlying cause to restore proper vehicle operation.

How Severe is this DTC?

Stored IMRC codes will typically result in open intake manifold runner control flaps. The P200A should not be classified as severe but should be addressed as soon as possible.

What are Some of the Symptoms of the Code?

Symptoms of a P200A trouble code may include:

• Reduced fuel efficiency
• Reduced engine performance
• Lean or rich exhaust codes are stored
• Hesitation during acceleration
• Rough idling

What are Some Common Causes of the Code?

Causes of this code may include:

• Broken or worn IMRC linkage or bushings
• Faulty IMRC actuator
• Cracked or collapsed IMRC vacuum lines
• Defective IMRC vacuum supply actuator
• Open or shorted IMRC circuits or connectors
• Faulty IMRC sensor or other engine sensor(s)

What are the P200A Troubleshooting Steps?

If mass airflow (MAF), manifold absolute pressure (MAP), or intake air temperature (IAT) codes are stored, they should be addressed before attempting to diagnose the stored P200A.

If you can find a technical service bulletin (TSB) that matches the vehicle’s year, make, and model, as well as the engine size, stored codes, and presented symptoms, it can provide helpful diagnostic information. A diagnostic scanner, digital volt/ohmmeter (DVOM), hand vacuum pump, and vehicle-specific diagnostic information source will be needed to diagnose a P200A code.

I like to start my diagnosis with a visual inspection of the IMRC system. I focus on mechanical linkages, vacuum hoses and pipes, as well as electrical wiring and connectors. Worn or damaged hardware, bushings, or IMRC linkage should be repaired or replaced before proceeding.

I would proceed by locating the vehicle’s diagnostic connector, plugging in the scanner, and retrieving all stored codes and relevant freeze frame data. It’s a good idea to record this information before clearing the codes, in case the code proves to be intermittent. Once this is done, test drive the vehicle until the PCM enters readiness mode or the code resets. Assume the code is intermittent and will be much harder to diagnose if the PCM enters readiness mode. At this point, the conditions that led to the code being stored may need to worsen before an accurate diagnosis can be made.

Component testing procedures (and specifications), diagnostic flowcharts, connector pinout diagrams, and connector face views will be needed to complete the next step of your diagnosis.

With the key on and engine off (KOEO), use the vacuum pump to actuate the IMRC system for the relevant engine bank. Once vacuum pressure is applied to the IMRC actuator, verify that the flaps open on demand. If they do, observe the scanner data to see if the IMRC sensors (if applicable) are functioning correctly. If discrepancies are detected, test the respective sensor(s) using the DVOM. Suspect sensors that do not meet manufacturer specifications are faulty.

If all sensors and circuits appear to be functioning as expected and the IMRC hardware is intact, use the DVOM to test the control solenoid(s) for the appropriate circuit. Actuator solenoids that do not meet manufacturer specifications should be considered faulty.

Suspect the PCM has failed or has a programming error only after all other possibilities have been exhausted.

How Serious Is This DTC?

Stored IMRC codes will typically result in open intake manifold runner control flaps. The P200A should not be classified as severe but should be addressed as soon as possible.

What Are Some of the Symptoms of the Code?

Symptoms of a P200B fault code may include:

• Reduced fuel efficiency
• Decreased engine performance
• Lean or rich exhaust codes stored
• Hesitation during acceleration
• Rough idling

What Are Some Common Causes of the Code?

Causes of this code may include:

• Broken or worn IMRC linkage or bushings
• Faulty IMRC actuator
• Cracked or collapsed IMRC vacuum lines
• Defective IMRC vacuum supply actuator
• Open or shorted IMRC circuits or connectors
• Faulty IMRC sensor or other engine sensor(s)

What Are the Troubleshooting Steps for P200B?

If mass airflow (MAF), manifold absolute pressure (MAP), or intake air temperature (IAT) codes are stored, they should be addressed before attempting to diagnose the stored P200B.

If you can find a technical service bulletin (TSB) that matches the vehicle’s year, make, and model, as well as the engine size, stored codes, and presented symptoms, it may provide useful diagnostic information. A diagnostic scanner, digital volt/ohmmeter (DVOM), hand vacuum pump, and vehicle-specific diagnostic information source will be needed to diagnose a P200B code.

I prefer to start my diagnosis with a visual inspection of the IMRC system. I focus on mechanical linkages, vacuum lines and hoses, as well as wiring harnesses and electrical connectors. Worn or damaged hardware, bushings, or IMRC linkage should be repaired or replaced before proceeding.

I would proceed by locating the vehicle’s diagnostic connector, connecting the scanner, and retrieving all stored codes and relevant freeze frame data. It’s a good idea to record this information before clearing the codes, in case the code proves to be intermittent. Once this is done, test-drive the vehicle until the PCM enters readiness mode or the code resets. If the code is intermittent, it will be much more difficult to diagnose if the PCM enters readiness mode. At this point, the conditions that led to the code being stored may need to worsen before an accurate diagnosis can be made.

Component testing procedures (and specifications), diagnostic flowcharts, connector pinout diagrams, and connector face views will be needed to complete the next stage of your diagnosis.

With the key on and engine off (KOEO), use the vacuum pump to actuate the IMRC system for the relevant engine bank. Once vacuum pressure is applied to the IMRC actuator, verify that the flaps open on demand. If they do, observe the scanner data to see if the IMRC sensors (if applicable) are functioning correctly. If discrepancies are detected, test the respective sensor(s) using the DVOM. Suspect sensors that do not meet manufacturer specifications as faulty.

If all sensors and circuits appear to be functioning as expected and the IMRC hardware is intact, use the DVOM to test the appropriate circuit’s control channel solenoid(s). Actuator solenoids that do not meet manufacturer specifications should be considered defective.

Suspect PCM failure or a programming error only after all other possibilities have been exhausted.