Vehicle: 22017 Infiniti Q50, AWD, L4-2.0L Turbo, Automatic Transmission/Transaxle

Mileage: 126,900 miles

Problem: This vehicle was towed to the shop. The customer said that his car had been stolen and when he got it back, the right front fender and right front door were damaged, the right curtain airbag was deployed, and the engine wouldn’t start. The customer also said the car was running fine before they stole it, and that the thieves had made a key then drove the vehicle for three days before wrecking the car and abandoning it.

Case Details: Upon further inspection, the technician found that the right inner tie rod was bent, the sunroof glass was broken, and there were Key System and Chassis Control System error messages displayed on the dash. He found no wiring damage inside the right door or right fender.

The technician performed a health report with his scan tool. Every module demonstrated communication except the transmission control module (TCM), and various modules showed the following diagnostic trouble codes (DTCs):

• ECM reported DTCs: U0104, U0164, U0212, U0101, U0122, U0103.U1000
• Steering and Traction System (STS) module reported DTCs: B1422, B1431, B0029, B0028
• AWD module reported DTC: U1000

The CAN Hi circuit showed 2.50 volts, and the CAN Lo circuit also showed 2.50 volts. Given the complexity of the problem, the technician decided to reach out to ALLDATA Tech-Assist for some diagnostic suggestions.

The Tech-Assist consultant advised starting the diagnostics with the lack of communication with the TCM. He said that this vehicle was equipped with a second battery in the trunk. A problem with the battery could cause communication issues with the TCM.

Confirmed Repair: The technician checked the battery in the trunk. It was dead. He replaced the battery and cleared all the DTCs. Communication with the TCM returned, and the engine started and ran fine. Easy fix!