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

asked by on February 13, 2017

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.

Check Engine Light is on Inspection $79.99 - $89.99 Get a Quote

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.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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

What others are asking

Check engine light keeps coming back on

Hello. I would need to know the exact codes to be able to give good information about this. If you have a reoccurring misfire code, then a compression test needs to be done to see if there is an internal...

Engine sputters when idle, does not hesitate or sputter when pressing accelerator.

The first thing to check for in any drivability problem is air leaks. Any air that gets into the engine without being measured will lean out the system and cause problems. Look at all the rubber hoses and boots under...

What does the electric stability control (ESC) indicator mean?

The electric stability control (ESC) indicator is located on the instrument panel. When the ESC light blinks, then system has detected adverse driving conditions, and the ESC is turned on. If the indicator illuminates and stays lit, then the ESC...

How do I check the coolant?

The coolant is a vital part of your vehicle, as it helps keep your engine from overheating. Periodically, you should check your coolant levels to make sure there’s enough in your vehicle. Here’s how: 1. Open the hood. 2. Locate...

How do i know what tensioner system my car has

Unless you want to open the timing cover to check, you can give any Dodge dealer your VIN number and they can tell you which tensioner was used. With the VIN number, the dealer can tell you if your car...

Changed battery, now the engine "chugs" at idle and while accelerating

If you disconnected or connected the battery with the key on or any accessory activated then you may have damaged the computer of the car. Firstly, have the Check Engine Light scanned to see what code is stored in memory....

How do I turn on or turn off the speed dependent volume control (SDVC)?

The speed dependent volume control (SDVC) is a feature that helps your volume adjust. When the SDVC is turned on, the volume will automatically adjust based on the vehicle speed, to combat road noise. Turning on or turning off the...

Full tank of gas, but it cut off on me...

This is an intermittent electrical fault, likely in the ignition system or an engine management sensor that is "failing". There is a decision tree (diagnostic) that mechanics employ to find the issue in cases like this. The only way to...

Service engine light is on.

I would ask for help from a mechanic with a scan tool to check what code is being set in your computer. Consider one of the mechanics from YourMechanic to come out with their equipment to diagnose why your car...

Related articles

P0203 OBD-II Trouble Code: Injector Circuit Malfunction - Cylinder 3
P0203 code definition P0203 is a general OBD2 code that points to a fault in the injector circuit. Note: This...
P004A OBD-II Trouble Code: Turbocharger/Supercharger Boost Control “A” Circuit/Open
P004A means there is an issue with the turbocharger or supercharger boost control in the “A” circuit due to malfunctioning boost sensor or intercooler
P0386 OBD-II Trouble Code: Crankshaft Position Sensor B Circuit Range Performance
P0386 means the crankshaft position sensor has produced excessive voltage that exceeds the manufacturer's specifications.