Code No. P0327: Detonation Sensor Circuit Low Input


OPERATION



  • A power voltage of 5 V is applied to the detonation sensor terminal from the engine-ECU connector terminal K/S.
  • The power voltage is earthed to the engine-ECU connector terminal K/SE from the detonation sensor connector terminal.

FUNCTION



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

TROUBLE JUDGMENT


Check Condition
  • More than 2 seconds have passed since the engine starting sequence was completed.
Judgement Criterion
  • Detonation sensor output voltage is less than 0.5 V for 2 seconds.

FAIL-SAFE AND BACKUP FUNCTION



  • Fix the ignition timing with an allowance against detonation.

PROBABLE CAUSES



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

DIAGNOSIS PROCEDURE

STEP 1. Check harness between detonation sensor connector terminal and engine-ECU connector terminal K/SE.

  • Check earthing line for open circuit and damage.

Q. Is the check result normal?
Go to Step 2.
Repair or replace the connector, or repair the damaged harness wire.

STEP 2. Check harness between detonation sensor terminal and engine-ECU connector terminal K/S.

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

Q. Is the check result normal?
Go to Step 3.
Repair or replace the connector, or repair the damaged harness wire.

STEP 3. M.U.T.-III diagnosis code

  • Reconfirmation of diagnosis code.

Q. Is diagnosis code set?
Go to Step 4.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 4. 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-ECU.
Check end.