Modes Of Operation

The PCM has 2 modes of operation. One is the Bypass mode during which the PCM does not apply 5 volts to the IC timing signal circuit, allowing the ICM to control the triggering of each coil for proper spark timing. The Bypass mode is used during each of the following conditions:

• Engine cranking.
• Engine running below a desired RPM.
• Default mode due to a system failure.

The other mode is the IC mode during which the PCM is receiving the 18X and the 3X reference pulses from the CKP sensor and is supplying 5 volts to the IC timing signal circuit. This allows the PCM to accurately control spark timing for all driving conditions.