Code No. P0032: Oxygen Sensor (front) Heater Circuit High Input
OPERATION
- Power is supplied to the heater power terminal (terminal
No. 1) of the oxygen sensor (front) connector from the engine control relay (terminal No. 2).
- The heater (terminal No. 2) of the oxygen sensor (front) connector is controlled
by the power transistor in the engine-ECU (terminal No. 34).
FUNCTION
- The power supply to the oxygen sensor (front) heater
is controlled by the ON/OFF control of the power transistor in the engine-ECU.
- Heating the oxygen sensor (front) heater enables the oxygen sensor (front) to provide
good response even when the exhaust emission temperature is low.
TROUBLE JUDGMENT
Check Conditions
- More than 2 seconds have passed since the engine starting sequence was completed.
- While the oxygen sensor (front) heater is on.
- Battery positive voltage is more than 11 V and is less than 16.5 V.
- The oxygen sensor (front) heater current is more than 10.5 A for 2 seconds.
FAIL-SAFE AND BACKUP FUNCTION
- None
PROBABLE CAUSES
- Failed oxygen sensor (front) heater
- Short circuit in oxygen sensor (front) heater circuit or loose connector contact
- Failed engine-ECU
DIAGNOSIS PROCEDURE |
STEP 1. Connector check: C-45 oxygen sensor (front) connector |
Q.
Is the check result normal?
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Go to Step 2 . |
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Repair or replace the connector. |
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STEP 2. Perform resistance measurement at C-45 oxygen sensor (front) connector. |
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OK: 4.5 - 8.0 Ω (at 20°C) |
Q.
Is the check result normal?
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Go to Step 3 . |
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Replace the oxygen sensor (front). |
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STEP 3. Connector check: A-33X engine control relay connector |
Q.
Is the check result normal?
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Go to Step 4 . |
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Repair or replace the connector. |
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STEP 4. Check harness between A-33X (terminal No. 2) engine control relay connector and C-45 (terminal No. 1) oxygen sensor (front) connector. |
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Q.
Is the check result normal?
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Go to Step 5 . |
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Repair the damaged harness wire. |
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STEP 5. Connector check: B-08 engine-ECU connector |
Q.
Is the check result normal?
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Go to Step 6 . |
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Repair or replace the connector. |
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STEP 6. Check harness between C-45 (terminal No. 2) oxygen sensor (front) connector and B-08 (terminal No. 34) engine-ECU connector. |
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Q.
Is the check result normal?
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Go to Step 7 . |
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Repair the damaged harness wire. |
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STEP 7. M.U.T.-III diagnosis code |
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Q.
Is diagnosis code set?
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Replace the engine-ECU. |
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Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection
Service Points - How to Cope with Intermittent Malfunctions ). |
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