Symptoms
Symptoms of a P2019 engine code may include:
- Malfunction Indicator Lamp (MIL) illuminated
- Lack of power
- Occasional misfires
- Poor fuel economy
Causes
Typically, the causes for this code to set are as follows:
- Sticking/faulty throttle plates/body
- Sticking/faulty IMRC valve (bank 2)
- Faulty IMRC actuator/sensor
- Rarely – Faulty Powertrain Control Module (PCM)
Diagnostic Steps
and Repair Information
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 released 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 intake/engine performance system, diagnose those first. Misdiagnosis is known to occur if a technician diagnoses this code before any intake/engine performance-related system codes 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 according to the Air/Fuel Ratio (AFR) or Oxygen (O2) sensor.
Next, locate the IMRC valve/sensor on your specific vehicle. 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 perhaps 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 available, find 91% isopropyl alcohol and a soft plastic-bristled brush to clean them (an inexpensive toothbrush will work here; do not return it to the bathroom after use!). Then, let them air dry, get some dielectric silicone compound (the same type 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 issue.
If the code returns, we will need to test the voltage signals to and from the IMRC valve/sensor and the PCM. Monitor the IMRC sensor voltage on your scan tool. If no scan tool is available, test the signal from the IMRC sensor with a Digital Volt-Ohm Meter (DVOM). With the sensor connected, attach the red voltmeter lead to the IMRC sensor signal wire and the black voltmeter lead to ground. Start the engine and monitor the IMRC sensor input. Quickly press the accelerator. As engine RPM increases, the IMRC sensor signal should change. Check the manufacturer’s specifications, as there may be a chart indicating the voltage at a given RPM.
If it fails this test, you will need to verify that the IMRC valve will move and is not stuck or binding inside the intake manifold. Remove the IMRC sensor/actuator and grasp the pin or linkage that moves the plates/valves inside the intake manifold. Keep in mind that these may have a strong return spring, so there might be tension when you turn them. Check if the plates/valves are binding/loose as you turn them. If they are, you will need to replace them, which typically means replacing the entire intake manifold. It is best to leave this task to professionals.
If the IMRC plates/valves turn without any binding or excessive looseness, this would indicate the need to replace the IMRC sensor/actuator and retest.
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. It cannot be stressed enough that once the first or first couple of diagnostic steps are performed and the issue is not obvious, it would be wise to consult an automotive professional regarding the repair of your vehicle, as most repairs from this point forward require the removal and replacement of the intake manifold to properly fix this code and the related engine performance issue.