Gear Shift Control Module A Supply Voltage High
The gear shift control module A reports a supply voltage above the operating range.
Affected components
- Gear shift module a
- Charging system
Common causes
- High likelihood: Alternator regulator failed to limit output
- Low likelihood: Load dump transient after disconnecting a heavy load
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.