P1168

P1168 CLOSED LOOP CONTROL

On Board Diagnosis Logic
- The closed loop control has the one trip detection logic.

Malfunction is detected when the closed loop control function for right bank does not operate even when vehicle is driving in the specified condition, the closed loop control function for left bank does not operate even when vehicle is driving in the specified condition.

POSSIBLE CAUSE
- The heated oxygen sensor 1 circuit is open or shorted.
- Heated oxygen sensor 1
- Heated oxygen sensor 1 heater

DTC Confirmation Procedure

CAUTION: Always drive vehicle at a safe speed.

NOTE: If "DTC Confirmation Procedure" has been previously conducted, always turn ignition switch OFF and wait at least 5 seconds before conducting the next test.

TESTING CONDITION:
- Never raise engine speed above 3,200 rpm during the "DTC Confirmation Procedure". If the engine speed limit is exceeded, retry the procedure from step 2.
- Before performing the following procedure, confirm that battery voltage is more than 11 V at idle.

With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select "DATA MONITOR" mode with CONSULT-II.




3. Hold engine speed at 2,000 rpm and check one of the following.

- "HO2S(1) (B1)/(B2)" voltage should go above 0.70 V at least once.
- "HO2S(1) (B1)/(B2)" voltage should go below 0.21 V at least once.

If the check result is NG, perform "Diagnosis Procedure".

If the check result is OK, perform the following step.

4. Let engine idle at least 5 minutes.




5. Maintain the above condition at least 50 consecutive seconds.

During this test, P0134 and/or P0154 may be displayed on CONSULT-II screen.

6. If DTC is detected, go to "Diagnostic Procedure" below.




Overall Function Check
Use this procedure to check the overall function of the closed loop control. During this check, a DTC might not be confirmed.

Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Set voltmeter probes between ECM terminal 50 [heated oxygen sensor 1 (bank 1) signal] or 51 [heated oxygen sensor 1 (bank 2) signal] and engine ground.
3. Check the following with engine speed held at 2,000 rpm constant under no-load.

- The voltage should go above 0.70 V at least once.
- The voltage should go below 0.21 V at least once.

4. If NG, go to "Diagnostic Procedure" below.

Diagnostic Procedure

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