E012

ECM Code E012:

DFI HEI Circuit:

TEST CONDITIONS:

Code E012 is tested for during engine cranking (crank input to the ECM at system voltage and no code EO18 pending).

FAILURE CONDITIONS:

If the ECM does not see distributor reference pulses for 2.1 seconds with crank input to the ECM at system voltage, current code E012 will be set.

ACTION TAKEN:

1. The ECM turns on "SERVICE ENGINE SOON" telltale.
2. The ECM commands BCM to display "SERVICE CAR SOON" message on CCDIC.

Possible causes of "no distributor reference" are:

1. Open pick-up coil - the pick-up coil produces an A.C. voltage that is used by the HEI module to create distributor reference pulses.
2. HEI module unable to process pick-up coil signals.
3. Open or shorts on CKT 430 and 453 from module to 4-way weatherpack to ECM.
4. Loss of 12 volts to "BAT" terminal on HEI.

NOTES ON FAULT TREE:

1. Checking for proper voltage output of the HEI system. If the voltmeter shows .5 to 2.8 volts, then HEI is producing reference pulses.

2. Checking for proper ground connection between the ECM and the engine and the ECM and HEI.

3. Checking for proper voltage through CKT 43ORS from HEI to the ECM. If ECM terminal A7 sees .5 to 2.8 volts, then the ECM is receiving reference pulses.

4. If the HEI system will produce a spark then fault is not at the pick-up coil or module. Check CKT 43OBS for opens or short to ground from module terminal "R" to pin "B" of 4-way weatherpack. If code E012 is stored as a history code, start engine and allow to idle while manipulating CKT's 430 and 453. An intermittent open will cause the engine to stumble or quit when the ECM loses distributor reference.

NOTE ON INTERMITTENTS:

If no trouble is found in the wiring and ECM connectors, check the HEI pick-up coil leads for an intermittent open circuit. Check for short to voltage on CKT 806, crank input to ECM pin B3. If pin B3 has voltage at key on - engine off, the ECM will record a false code E012. If found, repair short to voltage on CKT 806.