U0421
Invalid Data Received from Throttle/Pedal Position Sensor
The ECU receives implausible accelerator pedal or throttle data over the bus. The engine drops to limp-mode with reduced power.
The ECU receives implausible accelerator pedal or throttle data over the bus. The engine drops to limp-mode with reduced power.
Common causes
- medium
Pedal sensor partially failed
A plausible cause — test and verify before replacing parts.
Typical part cost: $90-550
- low
Gateway module routing CAN messages incorrectly
Less common, but worth ruling out after the more likely causes.
Typical part cost: $90-550
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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 U0421 mean?
U0421 means "Invalid Data Received from Throttle/Pedal Position Sensor". It is a generic OBD-II code that points to a fault in the network / communication.
What are the most common causes of U0421?
pedal sensor partially failed; gateway module routing can messages incorrectly; can terminating resistor (120 ω) drifted out of spec — 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?
This code can put the vehicle into limp or reduced-power mode. Avoid extended driving and have the vehicle diagnosed promptly. Use the Wrenchify app for a full diagnosis specific to your vehicle.
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