Fault-Code Library · Throttle control
P0121: Throttle / pedal position sensor range / performance
The ECU sees a throttle or accelerator-position signal that is outside the expected relationship.
Common symptoms
- •Limp mode
- •Poor throttle response
- •Stalling
- •Electronic throttle warning
Likely causes
- •Throttle body wear or contamination
- •Accelerator pedal sensor fault
- •Connector or harness issue
- •Low voltage
First checks
- •Scan throttle and pedal live data
- •Inspect connectors and wiring
- •Check adaptation status and battery voltage
Important
Throttle-control faults can affect drivability suddenly; verify safe operation before road testing.
A fault code identifies a detected condition, not a failed part. Confirm manufacturer-specific subcodes and live data.
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