kizmazz

The Service Dash ligjts came on and it was for 2 bad knock sensors, which were replaced.
After installation of knock sensors they plugged their laptop in and there weren’t any codes.
shortly after leaving repair facility the Service Dash Ligjts came back on so returned and they
Checked and no codes appeared. I needed a new Sticker so took to the Test Station when
the lights went back off and car passed.
now the lights stay on all the time anyone experienced this issue?

maxSteel

Consider buying a code reader so you will know why the CEL is on.

kizmazz

I’ve had it read at different places including Texas Inspection and ZERO Codes show up.
they did install a new pigtail w knock sensors.
I just want to find out why the dash lights stay on.

salimshah

It would help is you post the error codes and to get error codes you need a reader or visit auto store to get it read for free. One should not assume the new error is the same as old.

Unfortunately the things one reads, should not be fully trusted. There is lot of misinformation and much more of well intended but still bad advice.

The dash check engine light is turned on by the ecu after getting information from sensors. At times the problem can be with the sensor going out and giving bad information, at times it can be the wires connectors and at times the issue is with the system itself. Example is at times a sensor or relay fails to activate in the vacuum plumbing or there can be a tear in the hose ... the ecu will light up the CEL and the reader will tell you which system is malfunctioning. Then the diagnosis will determine the real failing part.

Back to your case, it could be the señor, wire, connector or actual knock in the engine. After the repair the ECU was cleared and then it took time to determine the issue is still there [assuming you are getting the same knock sensor code]. Why it came back, it could be the new sensor is no good or ????

Once the codes are cleared, it takes a while to accumulate engine sensor data [there are tons of sensors] to light up the CEL. During this time, inspection stations will refuse to pass you, but once the channels are ready they will pass/fail based on what they read. Typically but not necessarily they will fail you if the CEL is lit. If the bulb is blown/removed, they will make the reading using the oBDII and determine pass/fail.

Salim

PS: A good starting point would be to return to the shop and ask them to have a look. They should provide warranty on parts/labor or it can be something new or even collateral damage.

kizmazz

Salim,
There are NOT any error codes or I would have posted them. 🤷🏽‍♂️
The repair facility replaced the Knock Sensors they replaced
previously with Toyota Knock Sensors , NO CODES.
I’ve taken it back to the ASE repair shop and NO CODES.
Ive taken it to Oreilly Auto parts NO CODES.
It’s difficult to repair something that won’t show an error code.

i thought someone in this group may have experienced the same thing
im experiencing and tell me how to get it repaired.
Thanks!

Ron

salimshah

Are we talking about the same thing ...

CEL check engine light ... engine symbol amber/yellow. This light should turn on, when you move the key from ACC to run [before start] and once you start the light turns off with-in fraction of a minute. If it stays on an OBD code reader then can give you error code to interpret what has gone wrong [this is not mother of all problems, but are mostly emission related issues]. In all vehicles sold in USA since 1995. You would typically need this unlit to get an inspection. The inspection station will still connect a reader to confirm there are no emission issues. If your reader pr shop reader shows no codes, you can try your luck at the inspection station. A savvy inspector will pass you with a clean OBDII read. They will still need all channels ready to ensure the engine has had enough time to accumulate engine data and no one has just reset the error code. [This is the one I was talking about]

Service due is a reminder that an oil change or filter change is needed. This light if equipped on vehicle is set by the dealer to come on at say every 5000/10000 miles. Depending on your model year it can come on at 4500 for wheel rotation needed [small service] and 10,000 oil + filter change . This light needs to be reset after performing the service.

Please post to clarify.

Salim