Transmission Park Position Sensor/Switch A/B Correlation
The two redundant park position sensors A and B disagree — one reports Park, the other does not. Until the discrepancy is cleared the TCM cannot trust either reading and falls back to a safe state (typically blocking key removal and engine restart).
Affected components
- Park position sensor a
- Park position sensor b
Common causes
- High likelihood: One of the two sensors drifting outside tolerance
- Medium likelihood: Mis-adjusted shift lever mechanism
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
Related codes
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.