Exhaust Brake Input Circuit Low
Same as P04D3 with the signal voltage below the plausible range. The exhaust control valve modulates exhaust backpressure or routing (EGR feed, sound, regen support); a malfunction shifts torque mapping and may trigger limp mode.
Affected components
- Exhaust brake request switch
Common causes
- High likelihood: Signal shorted to ground
- Low likelihood: Connector pins corroded - high contact resistance
- Low likelihood: Harness chafing through insulation
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.