P061B

P061B-INTERNAL CONTROL MODULE TORQUE CALCULATION PERFORMANCE

For a complete wiring diagram Refer to the Wiring Information.

Theory of Operation

The purpose of the diagnostic is to monitor the positive engine torque request calculation in the Transmission Control Module (TCM) and the engine response resulting from the positive engine torque request. This diagnostic includes, comparison of the calculated torque request versus commanded torque request. The rationality of the actual crankshaft torque signal received from the PCM. The rationality of the actual input and output speed gradient of the transmission. The comparison of two torque request signals that are managed separately in the software which come after the torque request calculation but before the torque request is sent to the TCM.

- When Monitored:
After the ignition switch is turned to the run position and when an upshift is in progress.

- Set Condition:
Comparison of Calculated to Commanded Torque

A fault is detected if the shift control software does not command a positive torque request, but the calculated torque request signal is greater than zero.

Rationality of Actual Engine Torque

A fault is detected if the actual engine torque signal of the crankshaft does not correlate to the torque request from the TCM sent over CAN.

Rationality of Input and Output Speed Gradient

A fault is detected if the difference between the actual input speed gradient and the actual output speed gradient multiplied by the actual gear ratio is lower than a calibrated threshold.

Comparison of Two Separately Managed Torque Signals

A fault is detected if the two torque request signals that are managed separately in the software are not equal.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. 8HP45 Pre-Diagnostic Troubleshooting Procedure

TRANSMISSION CONTROL MODULE ASSEMBLY (TCMA)

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Repair

- Using the schematics as a guide, check the TCMA terminals for corrosion, damage or terminal push out. If no problems are found, reprogram the TCMA and Road Test the vehicle. If the DTC returns, replace and program the TCMA. Valve Body - Removal.
- Perform the TRANSMISSION VERIFICATION TEST. Verification Tests.