Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Inspection Procedure
HINT:
Read freeze frame data using the hand held tester or the OBD II scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.
- CHECK OTHER DTC OUTPUT (IN ADDITION P0121)
- Connect the hand held tester or the OBD II scan tool to the DLC3.
- Turn the ignition switch ON and push the hand held tester or the OBD II scan tool main switch ON.
- Select the item "DIAGNOSIS/ENHANCED OBD II/DTC INFO/CURRENT CODES."
- Read the DTCs.
Result:
DTC OUTPUT DISPLAYDisplay (DTC output) Proceed to P0121 and other DTCs A P0121 B HINT:
If any other codes besides P0121 is output, perform the troubleshooting for those DTCs first.
- B: REPLACE THROTTLE POSITION SENSOR
- A: GO TO RELEVANT DTC CHART (See DIAGNOSTIC TROUBLE CODE CHART )
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.