Engine Speed Input Circuit No Signal
The transmission control module receives no engine speed signal. Required to coordinate shifts and torque converter lockup with engine state.
Affected components
- Tcm
- Ecm
- Canbus
Common causes
- High likelihood: Speed signal lost on data bus
- Medium likelihood: Bus communication fault
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
- Reduced-power or limp mode may occur
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.