What does Error Code P0155 mean?
Moderate Issue
DTC Code P0155 indicates an O2 Sensor Heater Circuit Malfunction for Bank 2 Sensor 1. This code is triggered when the Engine Control Module (ECM) detects that the Heated Oxygen Sensor (HO2S) 1 heater current is out of factory specifications, affecting the sensor's ability to reach and maintain the required operating temperature.
What are the symptoms of Error Code P0155?
- Engine Light ON: The check engine light or service engine soon warning light illuminates, indicating a malfunction in the O2 sensor heater circuit for Bank 2 Sensor 1.
- Higher Fuel Consumption: The vehicle may experience increased fuel consumption due to the O2 sensor not functioning properly, leading to incorrect air-fuel mixture adjustments.
- Excessive Exhaust Smoke: There may be excessive exhaust smoke, which can be a result of improper combustion caused by the malfunctioning O2 sensor heater circuit.
What causes Error Code P0155?
- The heated oxygen sensor may be faulty, leading to incorrect readings and triggering the error code.
- An open or shorted harness in the heated oxygen sensor can disrupt the signal, causing a malfunction.
- Poor electrical connections in the sensor circuit can result in intermittent or failed communication with the ECM.
- A blown fuse in the sensor circuit can prevent the heater from functioning, affecting sensor performance.
- A malfunctioning Engine Control Module (ECM) can misinterpret sensor data, leading to erroneous error codes.
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How to fix Error Code P0155?
- Initial Inspection: Visually inspect the heated oxygen sensor (HO2S) and its wiring for any signs of damage, corrosion, or disconnection. Pay special attention to the connectors and wiring harness.
- Check the Fuse: Locate and inspect the heated oxygen sensor fuse. Ensure it is not blown. Replace the fuse if necessary and check if the DTC code clears.
- Test the Heater Circuit: Using a multimeter, measure the resistance of the heater circuit in the O2 sensor. Compare the reading with the manufacturer's specifications. A significant deviation indicates a faulty sensor.
- Inspect for Water Intrusion: Check for any signs of water intrusion in the sensor connector. Moisture can cause short circuits and lead to a blown fuse.
- Check Power Supply: Verify that the power supply to the heater circuit is within the specified range. Use a multimeter to check the voltage at the sensor connector.
- Replace the O2 Sensor: If all previous checks are satisfactory and the issue persists, replace the Bank 2 Sensor 1 O2 sensor. Clear the DTC code and test drive the vehicle to ensure the problem is resolved.