DTC P023: Ignition Control Circuit Problem: Action
- PCM turns on the "SERVICE ENGINE SOON" MIL.
- PCM controlled spark is disabled for ignition cycle.
- PCM disables EGR.
- Transaxle shift adapts are maintained at current levels.
NOTE:
Numbers in list refer to circled numbers in diagnostic flow charts, see Fig 1 and Fig 2
. For circuit identification see Fig 3.
- Check if Code P035 is set because a REF LO problem can cause other ignition problems.
- Checking to see if Code P023 was set during "CRANK" or while engine was running.
- Checking if there is a short to voltage on CKT 424 or if a PCM failure is causing the ignition control system to be in bypass spark control when it should not be.
- Checking to see if there is an open in CKT 423 that is causing no ignition control pulses to reach the ignition control module or if pulses are reaching the ignition control module and it is doing nothing with them.
- Checking for a short to voltage on CKT 424.
- Checking if bypass control is being sent by the PCM to the ignition control module. If bypass control is being sent the voltage will be greater than 4.1 volts.
- Checking if bypass control being sent by the PCM is being received by the ignition control module. If CKT 424 is good, resistance will be less than 5 ohms.
- Checking if PCM is providing proper signal to the ICM. If PCM terminal "3F3" has between 30 and 100 Hertz, the PCM is not at fault.
- Checking if PCM can produce the proper ignition control pulses. If Max voltage exceeds 3.7 volts, the PCM is OK and the ICM is at fault.
- Checking CKT 424 for a short to ground.
- Checking if the ICM is able to recognize a Bypass Signal. If it does, Code P023 will not set again. If Code P023 resets the ICM is faulty, if it does not reset the PCM is faulty.
- Checking if ICM is causing incorrect voltage or if PCM is supplying incorrect signal.