Code No. P1238: Air Flow Sensor Trustful For Torque Monitoring
FUNCTION
- Compare the actual measurement of volumetric efficiency by an air flow sensor signal with volumetric efficiency estimated from a throttle position sensor (main and sub) signal.
TROUBLE JUDGMENT
Check Conditions
- Difference between the actual volumetric efficiency and the volumetric efficiency estimated by the throttle position sensor (main) is more than 0 %. Or, the volumetric efficiency is less than 60 %.
- Engine speed is more than 750 r/min.
- Difference between the actual volumetric efficiency and the volumetric efficiency estimated by the throttle position sensor (main) is more than 35 %.
- Difference between the actual volumetric efficiency and the volumetric efficiency estimated by the throttle position sensor (sub) is more than 0 %. Or, the volumetric efficiency is less than 60 %.
- Engine speed is more than 750 r/min.
- Difference between the actual volumetric efficiency and the volumetric efficiency estimated by the throttle position sensor (sub) is more than 35 %.
FAIL-SAFE AND BACKUP FUNCTION
- Throttle opening degree position is in default position.
PROBABLE CAUSES
- Failed air flow sensor
- Harness damage in air flow sensor circuit or loose connector contact
- Failed engine-ECU
DIAGNOSIS PROCEDURE |
STEP 1. M.U.T.-III diagnosis code |
Q.
Is any other diagnosis code than P1238 set?
|
Inspection chart for diagnosis code (Refer to ). |
|
Go to Step 2. |
|
STEP 2. M.U.T.-III data list |
|
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 ). |
|