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:
It is possible that the malfunctioning area can be found using the ACTIVE TEST A/F CONTROL operation. The ACTIVE TEST can determine if the heated oxygen sensor or other potential trouble areas are malfunctioning or not.
The injection volume can be switched to -12.5% (decrease) or +25% (increase) by the ACTIVE TEST.
The ACTIVE TEST procedure enables a technician to check and graph the output voltage of the heated oxygen sensors.
Procedure:
- Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
- Turn the engine switch on (IG).
- Warm up the engine by running the engine at 2,500 rpm for approximately 90 seconds.
- Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.
- Perform the ACTIVE TEST while the engine is idling.
Standard:
The heated oxygen sensor reacts in accordance with the increase and decrease of injection volume:
+25% → RICH output: More than 0.55 V
-12.5% → LEAN output: Less than 0.4 V
If the vehicle is short on fuel, the air-fuel ratio becomes LEAN and the DTCs will be recorded.
Use the Manual With the Right Hardware
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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.
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