Code No. P0068: Trustful Check Air Flow Sensor

FUNCTION

Compare the actual measurement of volumetric efficiency by an air flow sensor signal with volumetric efficiency estimated from a throttle position sensor (main or sub) signal.

TROUBLE JUDGEMENT

Check Conditions

Engine is running.
Throttle position sensor (main or sub) is normal.

Judgement Criterion

The difference between volumetric efficiency (actual measurement) by the air flow sensor and volumetric efficiency estimated from the throttle position sensor (main) exceeds the specified value.

or

The difference between volumetric efficiency (actual measurement) by the air flow sensor and volumetric efficiency estimated from the throttle position sensor (sub) exceeds the specified value.

FAIL-SAFE AND BACKUP FUNCTION

Fuel control is carried out using throttle opening degree and engine speed in accordance with preset map.

PROBABLE CAUSES

Failed air flow sensor
Harness damage in air flow sensor circuit or loose connector contact
Failed intake air system
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Q. Is any other diagnosis code than P0068 set?

	Inspection chart for diagnosis code (Refer to ).

	Go to Step 2.

STEP 2. M.U.T.-III data list

Refer to Data List Reference Table .

Item 10: Air flow sensor

Q. Is the check result normal?

	Replace the engine-ECU.

	Check air flow sensor system. Check code No. P0102: air flow sensor circuit low input (Refer to ). Check code No. P0103: air flow sensor circuit high input (Refer to ).