This code indicates that the oxygen sensor is detecting rich or lean conditions in the exhaust. This can be caused by a number of factors, including:
- A faulty oxygen sensor
- A problem with the fuel injection system
- A problem with the ignition system
- A vacuum leak
- An exhaust leak
It is also possible that this code is due to a temporary condition, such as a dirty air filter or a low fuel level. If the code appears and disappears intermittently, it is a good idea to check these things first before taking your car to a mechanic.
Potential Symptoms
- Check Engine Light is on
- Engine is running rough
- Fuel efficiency is poor
- Engine hesitates or stalls
How to Fix
The first step is to diagnose the problem by reading the trouble codes from your car's computer. This can be done with a code reader. Once you have the code, you can start to troubleshoot the problem.
If the code is A135, the most likely culprit is the oxygen sensor. To test the oxygen sensor, you will need a voltmeter. Follow these steps:
- Disconnect the oxygen sensor from the wiring harness.
- Connect the positive lead of the voltmeter to the oxygen sensor signal wire.
- Connect the negative lead of the voltmeter to the oxygen sensor ground wire.
- Start the car and let it idle.
- The voltmeter should read between 0.1 and 0.9 volts. If it reads outside of this range, the oxygen sensor is faulty and needs to be replaced.
If the oxygen sensor is not faulty, the problem may be with the fuel injection system, the ignition system, or a vacuum leak. You will need to take your car to a mechanic for further diagnosis.
Cost of Repair
The cost to replace an oxygen sensor is around $100 to $200. The cost of labor to diagnose and repair the underlying problem will vary depending on the problem itself.
