Error P0155 – how to fix?

Error code definition P0155

O2 Oxygen Sensor Heating Circuit Malfunction (Bank 2 Sensor 1)

What does the code P0155 mean

When P0155 appears, the oxygen sensor heating element is taking longer than usual to heat up. The power control module (PCM) will record trouble code P0155 and the Check Engine light will illuminate to alert the vehicle operator of the problem.

What causes the code P0155?

• The oxygen sensor (bank 2, sensor 1) is not working properly.
• Damaged or bare wire to oxygen sensor.
• The fuse in the oxygen sensor circuit has blown.
• Engine coolant temperature sensor is not working as it should
• The power control module (PCM) is damaged (much less likely)

What are the symptoms of the P0155 code?

• The Check Engine light comes on
• Poor vehicle operation
• The vehicle uses more fuel than usual
• The vehicle turns off sporadically
• The exhaust fumes smell like rotten eggs
• Black smoke is coming out of the exhaust pipe
• Some or all of these symptoms may be with fault code P0155.

How does a mechanic diagnose fault code P0155?

In most cases, the presence of this code means that the oxygen sensor needs to be replaced. Before that, you must do the following:

• Use the OBD-II Scanner to pick up the fault codes that have been written by the Power Control Module (PCM).
• Visually inspect the wiring to the oxygen sensor for broken wires or bare wires.
• Use an OBD-II scanner to view live data to make sure the oxygen sensor is working properly.
• If the coolant temperature sensor is not working properly, the power control module (PCM) will also record this code, so it should be checked and tested.
• On rare occasions, PCM may be damaged and this requires advanced diagnostics to determine if this is the problem. This should be regarded as the last one and only after all other repair attempts have failed.

The most common errors when diagnosing the P0155 code

• Replace the oxygen sensor before checking other components.
• Failure to check the wires leading to the oxygen sensor for broken and / or scuffed wires before replacing the oxygen sensor.

How serious is trouble code P0155?

Trouble code P0155 is considered a moderately severe code. The reason is that driving problems and poor fuel economy are possible when this fault code is present.

What repairs can fix the P0155 code?

1. Repair damaged or bare cables.
2. Replace the coolant temperature sensor.
3. Replace the oxygen sensor
4. In the rare event that it is necessary, replace the Power Control Module (PCM).

Additional notes regarding code P0155

Removing the oxygen sensor can be difficult if the oxygen sensor kit and propane tank are not available. The oxygen sensor may be difficult to access depending on the vehicle. If the oxygen sensor has stuck in the exhaust gas, which is common, a heating element will be required to remove it.