Diagnostic Strategy

Diagnostic Strategy
Troubleshooting an electronically controlled automatic transmission is simplified by using the proven method of diagnosis. One of the most important things to remember is that there is a definite procedure to follow.
The PCM has an adaptive learn strategy to electronically control the transmission, which will automatically adjust the shift feel. When the battery has been disconnected, or a new battery installed, certain transmission operating parameters may be lost. The PCM must relearn these parameters. During this learning process you may experience slightly firm shifts, delayed, or early shifts. This operation is considered normal and will not affect the function of the transmission. Normal operation will return once these parameters are stored by the PCM.

Shift Solenoids-A, B, C, and D
Four On/Off shift solenoids allow the powertrain control module (PCM) to control shift scheduling.
- The solenoids are two-way, normally open style.
- The shift solenoids (SSA, SSB, SSC, and SSD) provide gear selection by controlling the pressures of the shift valves.
- SSD is also used to apply and release the coast clutch.

Torque Converter Clutch (TCC) Solenoid
The torque converter clutch (TCC) solenoid is used to control the apply and release of the TCC.

Powertrain Control Module (PCM)
The operation of the transmission is controlled by the powertrain control module (PCM). Many input sensors provide information to the PCM. The PCM then controls actuators, which determine transmission operation.

NOTE: Do not take any short cuts or assume that critical checks or adjustments have already been made.

Follow the procedures as written to avoid missing critical components or steps.
To correctly diagnose a concern have the following available:
- TSBs.
- Wiring Diagram.
These provide the information required when diagnosing transmission concerns.
Use the Diagnostic Flow Chart as a guide and follow the steps as indicated.

Preliminary Inspection
- Know and understand the customer's concern.
- Verify the concern by operating the vehicle.
- Check the fluid levels and condition.
- Check for non-factory add-on items.
- Check shift linkages for correct adjustment.
- Check TSBs regarding the concern.

Diagnostics
- Carry out on-board diagnostic procedures key on engine off (KOEO) and key on engine running (KOER).
- Record all diagnostic trouble codes (DTCs).
- Repair all non-transmission codes first.
- Repair all transmission codes second.
- Erase all continuous codes and attempt to repeat them.
- Repair all continuous codes.
- If only pass codes are obtained, refer to Diagnosis by Symptom for further information and diagnosis.
5R44E and 5R55E Automatic Transmission

Follow the diagnostic sequence to diagnose and repair the concern the first time.