Q: is it normal for an engine light that's been reset after service to come back on?

asked by on

after replacing an oxygen sensor-upstream- by your company mechanic on my car and he reset my engine light code. it stayed off when i drove home, but when i started the car up this morning, the engine light came back on and has stayed on. is this normal?

My car has 169000 miles.
My car has an automatic transmission.

Any given diagnostic trouble code will typically have multiple faults listed as potential causes of "the" code setting. It is possible for one fault (in your case an oxygen sensor that might not be putting out the expected waveform) to be addressed in a repair and yet additional faults exist where, again, the "additional" faults are related to the original code that was downloaded. However, it is also possible that the check engine light (CEL) has come on for a new reason (a new fault) that is completely unrelated to the code that involved the oxygen sensor. There are literally thousands of diagnostic trouble codes on modern vehicles, representing countless vehicle functions, that could cause the check engine light to come on. The only way to determine whether the CEL is presently illuminated because of a new or the "old" code is to have the codes read again. To do that, please request a check engine light diagnostic and, in the context of that you could request that the original mechanic come back as he will of course be most familiar with all of the circumstances. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. is it normal for an engine light that's been reset after service to come back on?

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Q: Check engine light

Hi there, thanks for your question. I'd be happy to help. A [misfire can be caused by a variety of things other than bad spark plugs such as bad plug wires, vacuum leak, dirty fuel injectors, a weak fuel pump...

Q: How do I adjust the sliding armrest?

The position of the sliding armrest can be adjusted to your liking. To move the armrest forward, simply pull it towards the front of the vehicle. To move the armrest backward, push it back toward the rear of the vehicle....

Q: Alternator amps

Hi There, Your vehicle should offer two options, one for 136 amps and one for 160 amps. Depending on the model you have (i.e. accessories, DVD player, rear AC, etc) you will want to purchase the 160 amp alternator. I...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...