P0121
Throttle Position Sensor/switch A Circuit Range/performance Problem
Description
Throttle Position Sensor/Switch A Circuit Range/Performance Problem This body system diagnostic trouble code indicates an issue with the vehicle's comfort, safety, or convenience systems.
OBD Codes Details
Possible Causes
Blown fuse, faulty switch, damaged wiring harness, poor electrical connection
Solution
Check fuses and relays, inspect wiring harness, test switches and sensors, repair damaged circuits
Symptoms
- Check engine light illuminated
- Erratic idle speed
- Hesitation or surging during acceleration
- Reduced engine power (limp mode possible)
- Poor throttle response
Diagnostic Recommendations
- Inspect throttle position sensor wiring and connector
- Test TPS signal voltage through its full range of motion
- Check throttle body for carbon buildup restricting movement
- Verify sensor is correctly calibrated after cleaning
- Replace TPS if voltage readings are erratic
Repair Cost Estimate
- TPS replacement: $80-250
- Throttle body cleaning: $80-150
- Wiring repair: $80-200
- Diagnostic scan: $80-150
- Total diagnostic and repair: $150-600
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Fact-checking completed
Verified by:
Pavel Volkov
Created:
Last updated:
Information verified against official sources
Official Sources
Society of Automotive Engineers
Official OBD-II diagnostic trouble codes standard (SAE J2012)
Automotive engineering standards organization
International Organization for Standardization
International standard for vehicle diagnostic systems
International standards for automotive diagnostics
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