Chart A1

The conditions diagnosed in ECM CHART A are caused by a single circuit failure that results in multiple diagnostic codes. If any of the following conditions are met, follow the appropriate correction procedure before using the procedures for the individual codes.

A-1
If Code EO22 is stored current accompanied by Code EO32 or EO40 also stored current, the cause is probably the loss of 5 volts on circuit #474 (5 volt reference to MAP, TPS, and the power steering sensor). To verify circuit #474 open as the cause of Code EO22 accompanied by Code EO32 or EO40, probe the following harness terminals with a voltmeter:
^ MAP sensor harness connector between Pin A and Pin C.
^ TPS sensor harness connector between Pin B and Pin C.
^ Power Steering sensor harness connector between Pin A and Pin C.

If the voltage is 0 volts at the connectors for all three sensors, circuit #474A must be investigated for an open between ECM terminal C14 and the circuit 474B/474C/474PN splice. Next check for a short to ground in circuit 474 between ECM terminal C14 and any of the three sensors. Refer to ECM Wiring Diagram - A. Electrical Diagrams

If the defect is not found in the wiring, either the ECM connector or ECM itself is faulty. Refer to PFI Chart C-1 "ECM Replacement Check" before replacing the ECM. Chart C-1 PCM/ECM Replacement Check

If the proper 5 volt signal is observed on any of the sensors terminals, then the diagnostic procedure for each individual code must be followed. Diagnose Code EO22 first, then Code EO32, and then Code EO40.