Code No. P1238: Manifold Absolute Pressure Sensor Trustful For Torque Monitoring


FUNCTION



  • Compare the actual measurement of manifold absolute pressure by an manifold absolute pressure sensor signal with manifold absolute pressure estimated from a throttle position sensor (main or sub) signal.

TROUBLE JUDGMENT


Check Conditions
  • Ignition switch is "ON" position.
  • While engine is running.
  • Throttle position sensor (main and sub) are normal.
Judgement Criteria
  • Difference is less than specified value between manifold absolute pressure of supposed throttle position sensor (main) signal and that of supposed throttle position sensor (sub) signal.
  • Difference is more than specified value between manifold absolute pressure of actual manifold absolute pressure sensor reading and that of supposed throttle position sensor (main) signal.
  • Difference is more than specified value between manifold absolute pressure of actual manifold absolute pressure sensor reading and that of supposed throttle position sensor (sub) signal.

FAIL-SAFE AND BACKUP FUNCTION



  • Throttle opening degree position is in default position.

PROBABLE CAUSES



  • Failed manifold absolute pressure sensor
  • Harness damage in manifold absolute pressure 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 P1238 output?
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 .

  1. Item 8: Manifold absolute pressure sensor

Q. Is the check result normal?
Go to Step 3 .
Check manifold absolute pressure sensor system. Check code No. P0107: manifold absolute pressure sensor circuit low input (Refer to ). Check code No. P0108: manifold absolute pressure sensor circuit high input (Refer to ).

STEP 3. Check air intake from inlet hose and inlet manifold.

Q. Is the check result normal?
Go to Step 4 .
Repair.

STEP 4. M.U.T.-III diagnosis code

  • Reconfirmation of diagnosis code.

Q. Is diagnosis code set?
Replace the engine-ECU.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).