Codes P1350/P1361, Ic Circuit: Notes
When engine is cranking, Ignition Control Module (ICM) sends a spark reference and a fuel control signal to PCM. At start of crank, ICM controls ignition timing (module mode). PCM sends a 5 volts signal on by-pass circuit to switch timing to PCM control when second fuel control pulse is recognized by PCM. Code P1350 will set at start-up is an open is present in ignition control circuit. Code P1361 will set if an open in Ignition Control (IC) circuit, or an open or grounded by-pass circuit is present during time when engine is started. Engine may be started but will run on module mode timing.
Code P1350 will set when following conditions are present.
- By-pass circuit shorts to voltage (3.4L only).
- IC circuit shorts to voltage (3.4L only).
- IC circuit opens during engine run mode.
Code P1361 will set when following conditions are present.
- IC circuit grounded during start-up.
Or
- PCM not commanding IC mode (open or grounded by-pass circuit) when engine is started.
When Codes P1350/P1361 are set, PCM will remove 5 volts bypass signal causing engine to run on module mode timing. PCM will illuminate Malfunction Indicator Light (MIL).
- Checks if PCM recognizes a problem. If Codes P1350/P1361 are not set, problem is intermittent and could be caused by a loose connection.
- With PCM disconnected, ohmmeter reading should be less than 2000 ohms, which is normal resistance of IC circuit through ICM. A higher resistance indicates a fault in IC circuit, a poor ignition module connection, or a faulty ICM.
- If test light lights when connected between 12 volts and PCM by-pass circuit terminal, then either by-pass circuit is shorted to ground, or ICM is faulty.
- Checks if ICM switches when by-pass circuit is energized by 12 volts through test light. If ICM switches, ohmmeter reading should shift to greater than 6000 ohms.
- Disconnecting ICM should make ohmmeter read as if an open circuit was being monitored (infinite reading). Otherwise, IC circuit is shorted to ground.