P0372

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The distributor ignition system supplies two timing inputs to the PCM, a high resolution signal (180 pulses per one crankshaft revolution) and a low resolution signal (4 pulses per one crankshaft revolution). The high resolution and low resolution circuits toggle between 0 and 5 volts as the camshaft turns. The PCM can determine if one of the timing inputs is not being received by comparing the two inputs.

The following malfunctions to the high resolution circuit will cause a DTC P0372 to set:

^ An open.

^ A short to voltage.

^ A short to ground.

^ A defective ignition module within the distributor.

CONDITIONS FOR SETTING THE DTC

^ The PCM detects low resolution pulses but no high resolution pulses.

ACTION TAKEN WHEN THE DTC SETS

^ The PCM will illuminate the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.

^ The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and/or Failure Records.

^ The injector will be disabled for the entire ignition cycle.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail.

^ A last test failed (Current DTC) will clear when the diagnostic runs and does not fail.

^ A History DTC will clear after forty consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

^ PCM battery voltage is interrupted.

^ Using a Scan tool.

DIAGNOSTIC AIDS

^ If DTC P1351 and/or DTC P1361 is also set with a DTC P0372, and no external fault can be found, replace the PCM. If only DTC P0372 is set and the distributor connections are OK, replace the distributor.

^ If distributor components must be replaced, check distributor vent system operation.

^ For intermittents, refer to Symptoms. Testing and Inspection

TEST DESCRIPTION

Number(s) below refer to step numbers on the diagnostic table.

2. This verifies if the malfunction is present. The engine may experience a extremely long crank time if the high resolution circuit is open, shorted to B+, or shorted to ground.

3. Using Freeze Frame Data may aid in locating an intermittent condition.

4. Normal voltage may vary slightly from the specified value. A value that is significantly higher or lower indicates a problem. This step isolates the circuit between the PCM and the test connector.

5. Normal voltage may vary slightly from the specified value. A value that is significantly higher or lower indicates a problem. This step isolates the circuit between the test connector and the distributor.