P0136 Toyota
Diagnostic Trouble Code (DTC) P0136 for Toyota vehicles is related to the oxygen sensor in the exhaust system:
Code Definition
- P0136: O2 Sensor Circuit Malfunction (Bank 1, Sensor 2)
What It Means
The Powertrain Control Module (PCM) or Engine Control Module (ECM) detects a malfunction in the circuit of the downstream oxygen sensor (Sensor 2) on Bank 1. This sensor monitors the efficiency of the catalytic converter.
Common Causes
- Faulty Oxygen Sensor (Bank 1, Sensor 2):
- The sensor itself may be damaged or worn out.
- Wiring Issues:
- Frayed, corroded, or damaged wires leading to the sensor.
- Exhaust Leaks:
- A leak near the sensor may cause inaccurate readings.
- Faulty PCM/ECM:
- Rare, but possible if the circuit itself has no issues.
- Contaminated Sensor:
- Caused by oil, coolant, or other contaminants in the exhaust.
Symptoms
- Check Engine Light illuminated.
- Decreased fuel efficiency.
- Rough idling or engine hesitation (in rare cases).
- Vehicle fails emissions tests.
Diagnostic Steps
- Check for Stored Codes:
- Verify the P0136 code using an OBD-II scanner and check for additional codes.
- Visual Inspection:
- Inspect the sensor wiring and connector for damage.
- Check for Exhaust Leaks:
- Look for leaks near the catalytic converter or sensor.
- Test the Sensor:
- Use a multimeter to test the voltage output of the oxygen sensor.
- Examine Catalytic Converter:
- Ensure it is functioning correctly if the oxygen sensor shows abnormal readings.
Repair Solutions
- Replace the downstream oxygen sensor (Bank 1, Sensor 2) if faulty.
- Repair or replace damaged wiring or connectors.
- Fix any exhaust leaks near the sensor.
- In rare cases, replace the PCM/ECM if confirmed faulty.
Prevention Tips
- Regularly inspect and maintain the exhaust system.
- Address oil or coolant leaks to avoid sensor contamination.
- Use high-quality fuel to reduce deposits in the exhaust system.