This code indicates that the oxygen sensor located in the exhaust manifold after the catalytic converter is detecting a voltage that is higher than expected. This can be caused by a number of factors, including:
- A faulty oxygen sensor
- A short in the oxygen sensor wiring
- A problem with the engine management computer
Symptoms of P0138
The symptoms of P0138 can vary, depending on the severity of the problem. In some cases, the only symptom may be a check engine light. In other cases, the vehicle may experience:
- Reduced fuel economy
- Rough idling
- Engine knocking
- Stalling
Causes of P0138
The most common causes of P0138 are:
- A faulty oxygen sensor
- A short in the oxygen sensor wiring
- A problem with the engine management computer
How to Fix P0138
The first step in fixing P0138 is to diagnose the cause of the problem. This can be done by a qualified mechanic using a diagnostic scan tool. Once the cause of the problem has been diagnosed, the mechanic can then repair the problem.
In most cases, P0138 can be fixed by replacing the faulty oxygen sensor. If the oxygen sensor wiring is shorted, the mechanic will need to repair the short. If the problem is with the engine management computer, the mechanic will need to replace the computer.
Cost of Fixing P0138
The cost of fixing P0138 will vary depending on the cause of the problem. In most cases, the cost will be between $100 and $200.
