Chart A Multiple Codes Stored Hard

ECM/PCM Chart A:

Sensor Circuit:

DESCRIPTION

The conditions diagnosed in PCM/ECM CHART A are caused by a single circuit failure yet result in multiple diagnostic codes. If any of these conditions are present, use these charts before using the procedures for the individual codes.

CHART A-1

If codes E22 and E32 are both stored hard, the cause is probably the loss of 5 volts on circuit #474 (5 volt reference to MAP and TPS and the power steering sensor).

To verify this condition, probe the following harness terminals with a voltmeter to ground:

1. MAP sensor harness connector pin A and C.
2. TPS sensor harness connector between pin B and C.

If the voltage is 0 for the two sensors, circuit #474 MUST be investigated for an open or short to ground between the PCM/ECM terminal C14 and both of the sensors. If a defect is not found in the wiring, either the PCM/ECM connector or PCM/ECM itself is faulty. If the proper 5 volt signal is observed on both sensor terminals, then the diagnostic procedures for each individual code must be followed. Diagnose E22 first, then code E32.

CHART A-2

If a code E15 is stored hard along with a hard code E21, or E40, the cause is probably an open in the sensor ground circuit #476 for the TPS and coolant sensors.

To verify this condition, probe the following harness terminals with a voltmeter to 12 volts:

1. TPS connector pin B, blk/pnk wire.
2. Coolant Temp sensor Pin A.

If the voltage is 0 at both sensors, circuit #476 be investigated for an open between the PCM/ECM terminal E11 and the sensors. If a defect is not found in the wiring, either the PCM/ECM connector or PCM/ECM itself is faulty. If 12 volts is observed at either of the two sensors, then the diagnostic procedures for each individual code must be followed. Diagnose code E15 then E21.

ECM/PCM Chart A (Cont.):

CHART A-3

If a code E34 is stored hard along with hard codes E38, this is probably caused by an open in the sensor ground circuit #469 for the MAP, MAT sensors.

To verify this condition, probe the following harness terminals with a voltmeter to 12 volts:

1. MAT sensor Pin A.
2. MAP sensor harness Pin A.

If the voltage is 0 for the sensors, circuit #469 must be investigated for an open between the PCM/ECM terminal A5 and the sensors. If a defect is not found in the wiring, either the PCM/ECM connector or PCM/ECM itself is faulty. If 12 volts is observed at the sensors, then the diagnostic procedures for each individual code must be followed. Diagnose code E34 then E38.