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Home >> Jeep >> 2013 >> Grand Cherokee Laredo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 175 ((Transmission Control Module (TCM) - Electrical Diagnostics)) >> DTC Troubleshooting >> U1402-Implausible Engine Temperature Signal Received >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different car, the 2012 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK FOR CAN BUS DTCS 
    1. With the scan tool, check for CAN BUS DTCs.

      Are there any CAN BUS DTCs present?

      Yes 

      No 

      • Go To  2.
  2. CHECK IF ENGINE DTCS ARE PRESENT 
    1. With the scan tool, read engine DTCs.

      Are there any engine DTCs present?

      Yes 

      • Refer to DTC INDEX and perform the appropriate diagnostic procedure .
      • Refer to STANDARD PROCEDURE  and perform the NAG1 TRANSMISSION VERIFICATION TEST.

      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. Refer to MODULE, TRANSMISSION CONTROL, REMOVAL .
      • Refer to STANDARD PROCEDURE  and perform the NAG1 TRANSMISSION VERIFICATION TEST.