Symptoms
Symptoms of a P2021 engine code may include:
- Malfunction Indicator Lamp (MIL) illuminated
- Lack of power
- Poor fuel economy
Causes
Typically, the causes for this code to set are:
- Faulty IMRC actuator relay (if applicable), bank 2
- Faulty IMRC actuator/sensor bank 2
- Rarely – Faulty Powertrain Control Module (PCM)
- (Programming required after replacement)
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.
The next step in this process is to locate the Bank 2 IMRC valve/sensor on your specific vehicle. Once located, visually inspect the connectors and wiring. Look for chafing, scraping, bare wires, worn spots, or melted plastic connectors. Separate the connectors and carefully inspect the terminals (the metal parts) inside the connectors. Verify they are not burnt or corroded. If in doubt, obtain an electrical contact cleaner from any auto parts store if terminal cleaning is necessary. If not possible, get some rubbing alcohol and a small plastic-bristled brush (used toothbrush) to clean them. Once cleaned, let them air dry. Pack the connector cavity with a dielectric silicone compound (same as used for light bulb sockets and spark plug wires) and reassemble.
If you have a scan tool, clear the diagnostic 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 signals to and from the IMRC valve to the PCM. Monitor the IMRC valve voltage on your scan tool. If a scan tool is not available, test the signal going to the IMRC valve with a Digital Volt Ohm Meter (DVOM). With the valve disconnected, the red voltmeter lead should be attached to the IMRC valve power supply wire and the black voltmeter lead connected to ground. Turn the ignition switch to the “on” position and check the voltage. It should be fairly close to battery voltage (12 volts). If not, the circuit has the problem. If it has 12 volts, reconnect the wires to the valve and check the voltage on the ground wire (PCM control wire). It should also be fairly close to battery volts. If not, the IMRC valve/solenoid is suspected to be open/shorted at this point.
If all tests have passed so far and you still have the same code, check your scan tool and see if it can open and close the IMRC valve. This might be called an “actuator test,” “bi-directional test,” or “functional test” depending on the scan tool/vehicle manufacturer. If the scan tool has this capability and it can operate the IMRC valves, the problem is either resolved and a simple code clearing is all that remains, or a new PCM would be required. If the scan tool has the capability but is unable to move the valves, either a faulty ground circuit between the valve and the PCM is indicated, or a faulty PCM.
It cannot be overemphasized that once the first or first couple of diagnostic steps are performed and the problem is not obvious, it would be wise to consult an automotive professional regarding the repair of your vehicle, as repairs from this point may require the removal of the intake manifold in order to properly diagnose this code and the related engine performance issue.