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:
Hand held tester only:
Narrowing down the trouble area is possible by performing "A/F CONTROL" ACTIVE TEST (heated oxygen sensor or other trouble areas can be distinguished).
Perform ACTIVE TEST using hand-held tester (A/F CONTROL).
HINT:
"A/F CONTROL" is the ACTIVE TEST which changes the injection volume to -12.5 % or +25 %.
- Connect the hand-held tester to the DLC3 on the vehicle.
- Turn the ignition switch ON.
- Warm up the engine by running the engine speed at 2,500 RPM for approximately 90 seconds.
- Select the item "DIAGNOSIS/ENHANCED OBD II/ACTIVE TEST/A/F CONTROL".
- Perform "A/F CONTROL" with the engine in an idle condition (press the right or left button).
RESULT:
Heated oxygen sensor reacts in accordance with increase and decrease of injection volume
+25 % --> rich output: More than 0.55 V,
-12.5 % --> lean output: Less than 0.4 V
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.