My car is a 1996 Toyota Camry, 4cyl., automatic.
Check engine light came on, the code found was PO773. Took car to a transmission shop and they replaced (after doing a 2 hour check of engine and transmission) the solenoid shift sensor and wiring.
The car ran and runs great before/after repair.
The check engine light keeps coming back on (and remaining on after sitting overnight (after driving for a few miles and shutting car off and restarting). Took car back to the shop, they checked again (found nothing)and reset the code.
Why does the check engine light keep coming back on?
Do I need to keep driving the car and eventually the computer will read the car is fixed?
This is getting frustrating to say the least.
You may have a short in the wiring harness that pertains to that particular sensor, you may have a breaking wire that makes intermittent contact. It may also be possible that you have another code that is set, if the problems persist try to stick with the mechanic that performed your last test since the history is known at that shop.
If the check engine light is coming on there is still a fault in the system. The scan tool that they have may not be able to read it, or they may not know what to do with it. But the light doesn't come on with out a fault somewhere in the vehicle.
I'd try taking it to another shop when the light comes back on and get a second opinion.
180 Degrees Automotive
〉 Answered on Nov 10th, 2009 by Bogi Lateiner, Owner and Technician at 180 Degrees Automotive
I would have someone else scan for codes when the light comes back on. It seems unlikely to me that the light is coming on for no reason. Get a second opinion on the light. The light is supposed to illuminate if the engine computer detects a sensor that is "out of range". Each sensor in the car has a high and low voltage threshold that it will operate in. If the voltage goes outside of that threshold the computer will turn on the "Service Engine Soon" light.
〉 Answered on Nov 12th, 2009 by Judy Curry, Co-Founder and Vice President of Marketing at Currys Auto Service
Hello Donna- I would have to guess that the ECM (computer) may have a problem- codes once erased & then reset indicated by the check engine light should remain in the stored memory of the computer until erased again with a scan tool- so since it keeps occurring & yet the codes were erased - it may ECM problem- hope this helps- thanks Super Girls Auto.
〉 Answered on Nov 7th, 2009 by Laurie Sarno, Co-Owner at Super Girls Auto
It sounds like you may have an intermittent problem. You may want to leave your vehicle with the technician so that he/she can experience the problem first hand and attempt to diagnose the issue while it is occurring.
〉 Answered on Nov 9th, 2009 by Suzanne Grego, Technician at City of Philadelphia Fleet Management