Vehicle: 2015 Nissan-Datsun Versa Sedan, L4-1.6L, CVT Transaxle

Mileage: 76,098

Problem: This vehicle was brought to the shop because the malfunction indicator lamp was on. The customer also mentioned that the engine would hesitate when she shifted the transmission into reverse.

Details: 

The technician connected a scan tool and retrieved a P0705 - Transmission Range Sensor A (TRS) diagnostic trouble code (DTC). He replaced the TRS and tried to clear the DTC, but it would not erase. When he called ALLDATA Tech-Assist, the consultant suggested checking for moisture or water intrusion in either or both taillights and to pay close attention to the back-up lamp sockets.

The technician checked the taillights, he found a large amount of moisture in both. He called the ALLDATA Tech-Assist consultant to report what he had found and to ask what the connection was between the back-up lamps and the TRS.

The Tech-Assist consultant explained that, as you switch between gears, 12V battery power flows back to the transmission control module (TCM) to tell the module which gear was chosen. However, since the TRS also supplies power to the backup lamp circuit, the TCM is expecting to see a large voltage drop on the reverse signal control wire (should be slightly above zero volts).

All other lights are controlled by the body control module, but the back-up lights are powered directly through the TRS. If there’s corrosion in the taillight assemblies, the TCM will see higher voltage on the reverse signal line and set a P0705 DTC. It is recommended by the manufacturer that, if you see any signs of water or moisture, check the circuit boards and light bulb sockets for corrosion. If corrosion is present, replace the taillight assemblies, clear the DTC and see if the engine hesitation goes away when shifted into reverse.

Confirmed Repair: The tech found corrosion in both reverse lamp sockets and some on one of the circuit boards, so he replaced both lamp assemblies. After the repair he was able to clear the P0705 DTC. When shifting into reverse, the engine hesitation was gone. After a good test drive, the DTC did not return. Fixed!