Chart A3

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-3
If a Code EO34 is stored as current along with a current Code EO38 or EO59, the cause is probably an open in the sensor ground (circuit #476A) for the MAP, MAT, and Transmission Temperature sensors. To verify this condition, probe the following harness terminals with a voltmeter to 12 volts:
^ MAP Sensor Pin A, Blk/Pnk wire.
^ MAT Sensor Pin A, Blk/Pnk wire.
^ Trans Temp Sensor Pin B, Blk/Pnk wire.

If the voltage is 0 at all three sensors, circuit 476A must be checked for an open between the ECM terminal A5 and the circuit 476A to 476PF/476PM/476PV splice. 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 12 volt signal is observed on any of the sensors' terminals, then the diagnostic procedure for each individual code must be followed. Diagnose Code EO34 first, then Code EO38, and then EO59.