Code No. P0325: Detonation Sensor System








OPERATION



  • The sensor signal is input to the engine-A/T-ECU (terminal No. 93) from the detonation sensor (terminal No. 2).
  • The power voltage is earthed to the engine-A/T-ECU (terminal No. 103) from the detonation sensor (terminal No. 1).

FUNCTION



  • The detonation sensor detects the vibration of the cylinder block caused by detonation waves, and inputs a signal to the engine-A/T-ECU.
  • In response to the signal, the engine-A/T-ECU provides controls to retard the ignition timing when the detonation occurs.

TROUBLE JUDGMENT


Check Condition
  • Engine speed is more than 500 r/min.
Judgment Criterion
  • Detonation sensor output voltage is less than 0.5 V or is more than 2.25 V.

PROBABLE CAUSES



  • Failed detonation sensor
  • Open/short circuit or harness damage in detonation sensor circuit or loose connector contact
  • Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-112 detonation sensor connector

Q. Is the check result normal?
Go to Step 2 .
Repair or replace the connector.

STEP 2. Connector check: D-217 engine-A/T-ECU connector

Q. Is the check result normal?
Go to Step 3 .
Repair or replace the connector.

STEP 3. Check harness between B-112 (terminal No. 1) detonation sensor connector and D-217 (terminal No. 103) engine-A/T-ECU connector.
note Before checking harness, check intermediate connector B-103, and repair if necessary.

  • Check earthing line for open/short circuit and damage.

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

STEP 4. Check harness between B-112 (terminal No. 2) detonation sensor connector and D-217 (terminal No. 93) engine-A/T-ECU connector.
note Before checking harness, check intermediate connector B-103, and repair if necessary.

  • Check output line for open/short circuit and damage.

Q. Is the check result normal?
Go to Step 5 .
Repair the damaged harness wire.

STEP 5. M.U.T.-III diagnosis code

  • Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?
Go to Step 6 .
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 6. Replace the detonation sensor

  • After replacing the detonation sensor, reconfirm whether the diagnosis code is set.

Q. Is the diagnosis code set?
Replace the engine-A/T-ECU.
Check end.