[13B] MULTIPORT FUEL INJECTION (MPI) <4G64> - - TROUBLESHOOTING - INSPECTION PROCEDURE FOR DIAGNOSIS CODES - Code No. 31 Detonation Sensor System | PRINT PAGE / INDEX / PRIOR / NEXT

Code No. 31 Detonation Sensor System
OPERATION The sensor signal is inputted to the engine-A/T-ECU (terminal No. 90) 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 the ignition switch has been placed in the "ON" position, or 60 seconds later after the engine has started up. Engine speed of 2,500 r/min or more. Volumetric efficiency of 30% or more. Judgment Criterion The change amount of the detonation sensor output voltage (the detonation sensor peak voltage in every half a turn of the crankshaft) is below 0.06 V in 200 consecutive times.
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-103 detonation sensor connector
| Q: Is the check result normal? YES: Go to Step 2 . NO: Repair.
| STEP 2. Perform resistance measurement at B-103 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? YES: Go to Step 3 . NO: Check and repair harness between B-103 (terminal No. 2) detonation sensor connector and body earth. Check earthing line for open circuit and damage.
| STEP 3. Connector check: C-110 engine-A/T-ECU connector
| Q: Is the check result normal? YES: Go to Step 4 . NO: Repair.
| STEP 4. Check harness between B-103 (terminal No. 1) detonation sensor connector and C-110 (terminal No. 90) engine-A/T-ECU connector.
| Check output line for open/short circuit and damage. Q: Is the check result normal? YES: Go to Step 5 . NO: Repair.
| STEP 5. Check the trouble symptoms. Q: Does trouble symptom persist? YES: Go to Step 6 . NO: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ).
| STEP 6. Replace detonation sensor. After replacing the detonation sensor, re-check the trouble symptoms. Q: Does trouble symptom persist? YES: Replace engine-A/T-ECU. NO: Check end.

[13B] MULTIPORT FUEL INJECTION (MPI) <4G64> - - TROUBLESHOOTING - INSPECTION PROCEDURE FOR DIAGNOSIS CODES - Code No. 31 Detonation Sensor System | PRINT PAGE / INDEX / PRIOR / NEXT

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