P2779-AUTOSTICK DOWNSHIFT SWITCH CIRCUIT PERFORMANCE - ESM

For a complete wiring diagram Refer to Section 8W

• When Monitored:

  When in AutoStick mode.

• Set Condition:

  When the expected switch state is not correctly sensed by the Shifter Lever Assembly (SLA) Electronic Shift Module (ESM). If the upshift switch signal is detected as active in gear position other than drive or both upshift and downshift signals are active at the same time.

Always perform the NAG1 Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)

Theory of Operation

The AutoStick Switch is integrated into the Shift Lever Assembly. The gear requested by the AutoStick selection is then sent over the CAN C bus from the Electronic Shift Module (ESM) to the TCM to engage the requested gear.

Diagnostic Test

• Using the schematics as a guide, check the Shifter Lever Assembly (SLA) Electronic Shift Module (ESM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace the Shifter Lever Assembly per the Service Information. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1/SHIFT MECHANISM - REMOVAL)
• Perform NAG1 TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)