P0121 Code - Throttle Position Sensor 1 Performance
Quick Answer
The P0121 code indicates that there is a problem with the Throttle Position Sensor (TPS) 1 performance. Common causes include A faulty Throttle Position Sensor, Damaged or corroded wiring/connectors leading to the TPS, Issues with the throttle body. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0121 indicates Throttle Position Sensor 1 Performance.
- Common causes
- Common causes include A faulty Throttle Position Sensor, Damaged or corroded wiring/connectors leading to the TPS, Issues with the throttle body.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code P0121 Description
The P0121 code indicates that there is a problem with the Throttle Position Sensor (TPS) 1 performance. The TPS is a crucial component of the engine management system as it monitors the position of the throttle valve and sends this information to the Engine Control Module (ECM). The ECM then uses this data to adjust the air-fuel mixture for optimal engine performance.
Common Causes of P0121
- A faulty Throttle Position Sensor.
- Damaged or corroded wiring/connectors leading to the TPS.
- Issues with the throttle body.
- Electronic control module (ECM) malfunction.
- Environmental factors such as extreme temperatures affecting sensor performance.
Symptoms of P0121
- Poor acceleration or hesitation when pressing the gas pedal.
- Rough idling or stalling when coming to a stop.
- Inconsistent or surging engine performance.
- Check Engine Light illuminated on the dashboard.
- Reduced fuel efficiency.
How to Fix P0121
- Begin by connecting a diagnostic scanner to the vehicle's OBD-II port to retrieve the specific code and confirm the issue is related to the TPS.
- Inspect the wiring and connectors leading to the TPS for any signs of damage or corrosion. Repair or replace as needed.
- Test the TPS using a multimeter to ensure it is functioning correctly. Replace the TPS if it fails the test.
- Clear the error code from the ECM using the diagnostic scanner and test drive the vehicle to verify that the issue has been resolved.
- If the problem persists, further diagnostic testing may be required to identify any additional underlying issues.
Cost to Fix P0121
The typical repair costs for addressing a P0121 code can vary depending on the specific vehicle make and model, as well as the labor rates in your area. On average, the parts cost for a new Throttle Position Sensor ranges from $50 to $150, while the labor cost can range from $100 to $200. Overall, the total repair cost for this issue is typically in the range of $150 to $350. It's recommended to consult with a trusted mechanic or auto repair shop for a more accurate estimate based on your individual circumstances.
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Code P0121 Information for Specific Makes
- P0121 Acura — Throttle Position Sensor 'A' Out of Range
- P0121 Audi — Throttle/Pedal Position Sensor/Switch 'A' Circuit Range/Performance
- P0121 Buick — Throttle Position Sensor 1 Performance
- P0121 Cadillac — Throttle Position Sensor 1 Performance
- P0121 Chevrolet — Throttle Position Sensor 1 Performance
- P0121 Chrysler — Throttle Position Sensor 1 Performance
- P0121 Dodge — Throttle Position Sensor 1 Performance
- P0121 Ford — Throttle/Pedal Position Sensor/Switch 'A' Circuit Range/Performance
- P0121 GMC — Throttle Position Sensor 1 Performance
- P0121 Honda — Throttle Position Sensor 'A' Out of Range
- P0121 Hummer — Throttle Position Sensor 1 Performance
- P0121 Hyundai — Throttle/Pedal Position Sensor/Switch 'A' Circuit Range/Performance
- P0121 Infiniti — Throttle Position Sensor Circuit Range/Performance Problem
- P0121 Isuzu — Throttle Position Sensor 1 Performance
- P0121 Jaguar — Throttle/Pedal Position Sensor/Switch 'A' Circuit Range/Performance
- P0121 Jeep — Throttle Position Sensor 1 Performance
- P0121 KIA — Throttle Position Sensor Circuit Range/Performance Problem
- P0121 Lexus — Throttle / Pedal Position Sensor / Switch 'A' Circuit Range / Performance
- P0121 Mazda — Throttle Position Sensor Malfunction
- P0121 Mercedes-Benz — Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance Problem
- P0121 Mitsubishi — Throttle/Pedal Position Sensor/Switch 'A' Circuit Range/Performance
- P0121 Nissan — Throttle Position Sensor Circuit Range/Performance Problem
- P0121 Pontiac — Throttle Position Sensor 1 Performance
- P0121 Saturn — Throttle Position Sensor 1 Performance
- P0121 Scion — Throttle / Pedal Position Sensor / Switch 'A' Circuit Range / Performance
- P0121 Subaru — Throttle/Pedal Position Sensor/Switch 'A' Circuit Range/Performance
- P0121 Toyota — Throttle / Pedal Position Sensor / Switch 'A' Circuit Range / Performance
- P0121 Volkswagen — Throttle/Pedal Position Sensor/Switch 'A' Circuit Range/Performance
- P0121 Volvo — Throttle/Pedal Position Sensor/Switch 'A' Circuit Range/Performance
Frequently Asked Questions about P0121 Code
No Frequently Asked Questions about P0121 Code found.
Discuss the causes and fixes for P0121 OBDII Code
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I have 2000 GMC Savanna. I'm getting the code P0121. I replaced throttle posistioning sensor and I'm still getting the P0121 code and service engine light goes on and off randomly.
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My 08 Pontiac G5 reads code P0121 Throtle/Pedal Positioning sensor A, any idea where it's located?
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the throttle PEDAL position sensor is located on the throttle pedal itself.
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I'm working on a 2006 GMC envoy denali, with adjustable pedals, The first time we got this code I misread it and we replaced the throttle position sensor which is located on the throttle body, then when it happened again about 2 months later I actually paid attention to what the code reader said, apparently you can not buy just the throttle PEDAL position sensor, it comes on the throttle pedal and comes as one unit, so now I have replaced the throttle position sensor AND the entire throttle pedal with position sensor, and the stupid light came back on, how would a person find out how to test the circuit? I found when the light comes on it doesn't affect the drivability, but if you don't clear it or do something with it, after about 50 miles it puts the vehicle in "limp" mode, clear the codes and your good for maybe 30 or 40 miles the the light comes on again this is my wife's vehicle and I tell her.."I love working on your car, of course you know I'm a liar" she doesn't see the humor in it.I just need to know how to test the circuit so perhaps I can find a short or broken wire.
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If you have the P0121 code, then it means that one of the two Throttle Position Sensors (TPS) is not working properly, or that the PCM commanded the throttle motor (actuator) to open and the throttle motor is not opening.
With the connector connected to the throttle body, insert a pin in the connector to check the TPS voltage. Each sensor should measure 0.3 to 0.7V.
I hope this help, let me know if you have more questions.
Also, try cleaning the throttle body, before replacing any more part. FYI 90% of the times the problem is the throttle body assembly, not just the sensors.
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I have removed and completely cleaned the throttle body, I have replaced the throttle position sensor, code still pops up, I recently replaced the throttle position sensor (the one on the pedal) and did all the tests, the code still pops up and actually says the TAC motor control I have a picture of the TAC so I know what I'm looking for and have looked all under the dash and in the engine compartment for it and can not find it, I sent an email to a guy on a different forum who in turn sent me one back saying this model does not have a TAC module, the throttle is controlled by the ECM, I've tested every circuit and wire I could find but unfortunatly everything tests fine, except I can not test anything with the TAC module because I can not locate it, someone told me it's located on the firewall inside the vehicle way up high in the dash, drivers side, I can not see that far up without pulling half my dash out, could you tell me where this TAC is located?2006 GMC envoy denali, I just dont understand if this model doesnt have a TAC , why on earth would the code for TAC pop up? and my code reader actually say's "TAC control motor circuit"
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I assumed you have the 5.3L engine correct? if that is correct then there is no TAC Module, the ECM controls the TAC.
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