Chart 6 Multiple PCM Codes

Sensor Circuit:

CIRCUIT DESCRIPTION
Some powertrain components share common feeds and returns. Certain failures of these circuits will cause multiple codes to set.

If all of the Powertrain Control Module (PCM) codes in one group under MULTIPLE PCM CODES are set, perform the diagnosis located under that heading. If all of the codes in a group are not set, diagnose the lowest code number first.

The electrical diagram in the accompanying image shows the relationship among the common feeds and/or returns.

MULTIPLE PCM CODES
1. PCM Codes PO22 and PO32 Set
CKT 474 is the 5 volt feed from the PCM to the Manifold Absolute Pressure (MAP) sensor and Throttle Position (TP) sensor. An open or short to ground in CKT 474 between the PCM's pin "1C14" and splice S215 will cause Codes PO22 and PO32 to set.

Diagnosis
Check for an open or short to ground on CKT 474 between PCM pins "1C14" and splice S215

2. PCM Codes PO31 and PO38 Set
CKT 452 is the sensor return to the PCM from the Intake Air Temperature (IAT) sensor and MAP sensor. An open in CKT 452 between splice S216 and PCM pin "2A5" will cause Codes PO31 and PO38 to set.

Diagnosis
Check for an open in CKT 452 between splices S216 and PCM pin "2A5."

3. PCM Codes PO15, PO21 and PO59 Set
CKT 808 is the sensor return to the PCM from the Engine Coolant Temperature (ECT) sensor, TP sensor and transaxle temperature sensor. An open CKT 808 between splice S217 and PCM will cause Codes P015, P021 and PO59 to set.

Diagnosis
Check for an open in CKT 808 between PCM pin "3E11" and splice S217.

4. PCM Codes PO39, PO4O and PO48 Set
CKT 741 is the battery feed from the engine compartment fuse block fuse "D1" to the Exhaust Gas Recirculation (EGR) solenoid, power steering pressure switch and the transaxle Torque Converter Clutch (TCC) solenoid. An open or short to ground in CKT 741 between fuse "D1" and splice S102 will cause Codes PO39, PO40 and PO48 to set.

Diagnosis
Check for and open or short to ground in CKT 741 between engine compartment fuse block fuse "D1" and splice S102.

- An open in CKT 741 between engine fuse block fuse "D1" and pin "A" of the TCC brake switch
- An open in CKT 420 between connector C101 pin "P10" and pin "B" of the TCC brake switch
- Open TCC brake switch