OBD-II code · Network
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.
Is it safe to drive with U0421?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- PossiblePedal sensor partially failed
- Less likelyGateway module routing CAN messages incorrectly
- Less likelyCAN terminating resistor (120 Ω) drifted out of spec
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.3–2 h
- Emissions test
- Usually unaffected
- Parts involved
- Accelerator Pedal Sensor, Throttle Actuator
Related codes
- U041EInvalid Data Received From All Wheel Drive Control Module
- U041FInvalid Data Received From Throttle Actuator B Control Module
- U0420Invalid Data Received from Power Steering Control Module
- U0422Invalid Data Received from Body Control Module
- U0423Invalid Data Received from Information Center
- U0424Invalid Data Received from HVAC Control Module
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.