Vehicle: 2020 Jeep Grand Cherokee, 4WD, V6-3.6L, Automatic Transmission/Transaxle

Mileage: 48,112 Miles

Problem: The vehicle was taken to a shop to have the top of the windshield tinted. After it was tinted, the vehicle would not start. NOTE: The mirror and rain sensor were removed from the windshield for tinting. The vehicle had no camera or ADAS components in the windshield. The vehicle was sublet to another shop for diagnosis and repairs.

Case Details: When the technician hooked-up a scan tool, there was no communication with the PCM. Fuse 78 in the Total Integrated Power Module (TIPM) had no power. The run/start relay would not turn on. If battery power was applied to fuse 78, the technician would get communication with PCM, but the engine still wouldn’t start.

The technician found numerous diagnostic trouble codes (DTCs). See DTCs in image below.

• C2118-92
• B2183-11
• B212E-11
• B2119-11
• B2123-11
• B2103-11

The TIPM was not receiving voltage from the BCM to activate the Run/Start relay, Accy1 and Accy2 relays. Pin 85 of run/start relay was only getting 6-volts at the relay. The battery was fully charged.

The BCM fuses were good as well as power and ground at the BCM. Occasionally during testing, the engine would crank and start but shut off after five seconds. The gear position indicator on the dash said the vehicle was in Drive when it was in Park. If the technician reset the BCM with the scan tool, the gear position indicator would read Park until he tried to start it. Then it would read Drive again. NOTE: If the BCM detects a problem with any relay, it will disable them.

A call went out to an ALLDATA Tech-Assist consultant. He advised that when performing a windshield tint job, the mirror and rain sensor are removed. That area contains the rain/light sensor module, LIN or CAN sub-network wiring and power/ground splices. Sometimes BCM-related circuits are routed up the A-pillar. The most likely problem would be damage to the harness or water contamination in the A-pillar or the BCM located below. He noted that it was very common after a tint job to have soapy water intrusion, a connector not fully seated, a pin spread, corrosion starting or a wiring harness pinched when reinstalling mirror/sensor. The technician decided to remove the BCM for inspection. He found some of the water/soap solution had leaked inside the BCM.

Confirmed Repair: After replacing the BCM, the vehicle started and ran normally. The technician reported that the new BCM required no programming. It picked up the VIN automatically and all the vehicle features worked with no warning lights or messages. Easy Fix!