Code No. P0325: Detonation Sensor System

OPERATION

The sensor signal is inputted to the engine-A/T-ECU (terminal No. 89) 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 Conditions

After 2 seconds have passed since the engine starting sequence was completed.
Volumetric efficiency is 40% or more.

Judgment Criteria

Change of detonation sensor output voltage (detonation sensor peak voltage in each 1/2 turn of the crankshaft) has not been 0.06 V or more in the last consecutive 200 periods.

PROBABLE CAUSE

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

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-24 detonation sensor connector

Q. Is the check result normal?

Go to Step 2 .

Repair or replace.

STEP 2. Perform resistance measurement at B-24 detonation sensor connector.

Disconnect connector, and measure at harness side.
Resistance between terminal No. 2 and earth.

OK: 2 Ω or less

Q. Is the check result normal?

Go to Step 3 .

Check earthing line for open circuit and damage.

STEP 3. Connector check: C-112 engine-A/T-ECU

Q. Is the check result normal?

Go to Step 4 .

Repair or replace.

STEP 4. Check harness between B-24 (terminal No. 1) detonation sensor connector and C-112 (terminal No. 89) engine-A/T-ECU connector.

Check output line for open/short circuit and damage.

Q. Is the check result normal?

Go to Step 5 .

Repair.

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

Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?

	Replace detonation sensor. Then go to Step 6 .

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ).

STEP 6. M.U.T.-III diagnosis code

Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?

	Replace engine-A/T-ECU.

	Check end.