Reverse Input Circuit
General electrical fault on the reverse-engagement input — the signal that tells the TCM (and other modules — backup lights, parking sensors) that the gear lever is in Reverse. With the input invalid backup lights and rear sensors do not activate.
Affected components
- Reverse input switch
- Wiring harness
Common causes
- High likelihood: Open or shorted reverse input wire
Possible symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Diagnostic notes
- The malfunction indicator lamp may illuminate
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.