P1077
DTC P1077: IMRC System Malfunction (Low rpm)Special Tools Required
Vacuum Pump/Gauge, 0 - 3 in.Hg A973X-041-XXXXX
1. Reset the ECM/PCM.
2. Start the engine, and hold it at 3,000 rpm with no load (in Park or neutral) until the radiator fan comes on.
Is DTC P1077 indicated?
YES - Go to step 3.
NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the intake manifold runner control (IMRC) solenoid valve and at the ECM/PCM.
3. Disconnect the vacuum hose (A) from the intake manifold runner control (IMRC) actuator (B), and connect a vacuum pump to the hose.
Is there vacuum with the engine at idle?
YES - Go to step 11.
NO - Go to step 4.
4. Check the vacuum hose between the IMRC actuator and IMRC solenoid valve.
Is the vacuum hose OK ?
YES - Go to step 5.
NO - Repair the blockage or vacuum leak between the IMRC actuator and IMRC solenoid valve.
5. Disconnect the lower vacuum hose (A) from the IMRC solenoid valve (B), and connect a vacuum pump to the hose.
Is there vacuum?
YES - Go to step 6.
NO - Repair the blockage or vacuum leak between the intake manifold and IMRC solenoid valve.
6. Reconnect the lower vacuum hose to the IMRC solenoid valve, and connect a vacuum pump to the vacuum hose(A).
7. Disconnect the IMRC solenoid valve 2P connector.
Is there vacuum?
YES - Go to step 8.
NO - Replace the IMRC solenoid valve.
8. Turn the ignition switch OFF.
9. Disconnect ECM/PCM connector B (24P).
10. Check for continuity between IMRC solenoid valve 2P connector terminal No. 2 and body ground.
Is there continuity?
YES - Repair short in the wire between the ECM/PCM (B22) and the IMRC solenoid valve.
NO - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.
11. Turn the ignition switch OFF.
12. Connect a vacuum pump to the IMRC actuator (A), then apply vacuum.
Does the IMRC actuator hold vacuum?
YES - Go to step 13.
NO - Replace the IMRC valve assembly.
13. Disconnect the IMRC valve position sensor 3P connector.
14. At the sensor side, measure resistance between IMRC valve position sensor 3P connector terminals No. 2 and No. 3 while applying vacuum to the IMRC actuator.
Is there about 9.5 kOhm?
YES - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.
NO - Replace the IMRC valve assembly.