Diagnostic Test

WARNING: This page is about a different car, the 2009 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.

CHECK THE FCM FOR DTCS
1. With the scan tool, check for FCM DTCs.
  Does the FCM report the DTC U0001-CAN C BUS DTC or U0121-LOST COMMUNICATION WITH ANTI-LOCK BRAKE MODULE?
  
  Yes
  - Refer to DTC Based Diagnostics and Non DTC Based Diagnostics for diagnostic procedures and other possible causes. Perform the diagnostic procedure for U0001-CAN C BUS DTC first if it is present. Refer to U0001-CAN C BUS .
  - Perform NAG1 TRANSMISSION VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Transmission Control (TCM) - Standard Procedure .
  No
  - Go to step 2.
CHECK FOR ABS DTCS
1. With the scan tool, read ABS DTCs.
  Are there any ABS DTCs present?
  
  Yes
  - Refer to the ABS and perform the appropriate symptom test. See DIAGNOSTIC CODE INDEX .
  - Perform NAG1 TRANSMISSION VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Transmission Control (TCM) - Standard Procedure .
  No
  - Using the schematics as a guide, check the Transmission Control Module (TCM) pins, terminals, and connectors for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace and program the TCM in accordance with the Service Information.
  - Perform NAG1 TRANSMISSION VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Transmission Control (TCM) - Standard Procedure