P04D3
Exhaust Brake Input Circuit
The exhaust brake activation input - typically from a stalk lever, brake pedal switch, or vehicle bus message - shows a circuit fault. The ECU cannot accept a request to engage the exhaust brake, which limits engine braking on heavy vehicles.
The exhaust brake activation input - typically from a stalk lever, brake pedal switch, or vehicle bus message - shows a circuit fault. The ECU cannot accept a request to engage the exhaust brake, which limits engine braking on heavy vehicles.
Common causes
- high
Open in switch circuit
One of the most commonly reported causes for this code — check this first.
Typical part cost: $130-500
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First things to check
- 1Confirm the code with a scan tool and check for additional related codes.
- 2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.
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Related codes
See related trouble codes
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Frequently asked questions
What does P04D3 mean?
P04D3 means "Exhaust Brake Input Circuit". It is a generic OBD-II code that points to a fault in the auxiliary emission controls.
What are the most common causes of P04D3?
open in switch circuit — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.
Can I keep driving with this code?
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.
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