ECU/Engine light issues

175,000 MILES
Avatar
JDOOLEY
  • MEMBER
  • 3 POSTS
The "Check engine" light is on. Had jiffylub, Autozone scan ECU but no codes were present. Took it to the SanTan Honda dealer to have the memory flashed/erased but the light is still on. Used all the shortcut tricks to erase memory, (disconnect batery cables, remove fuse #6, remove radio fuse, etc.) but light is still on.

Dealer says ECU is bad and needs a new one but:

1- with ignion key ON light comes on then off after a few seconds. Light comes back on AND STAYS ON once the engine is started.

2- If I remove a component (to create an error code such as the "oxygen sensor", light comes on with ignion key ON and won't go OFF. Once I reset the ECU then light goes off but still comes ON once the engine is started. THAT TO ME MEANS THE ECU IS WORKING, RECOGNIZED THE SENSOR WAS DISCONNECT AND REPORTED IT, RIGHT? So it would not be bad as the dealer says, or is it bad? So why wont the CHECK ENGINE light go off, and if the ecu seems to report errors why would it be bad?

ADDITIONHALLY - If you answer wire problem or bad ECU, then:

When key is in run position, all the check lights come on then go OFF after 3-4 seconds. "ABS, ENGINE, SEATBELT, etc." That's how it should be right? If I remove the wire from the oxygen sensor the CHECK ENGINE LIGHT STAYS ON. (that is the ECU reporting a trouble code) so, Would a bad computer report a trouble code and turn on the light? And if it reports trouble codes, why would it be BAD then, and why are there no codes when scanned eventhough it is turning the CHECK ENGINE light on with the oxygen sensor disconnect but will not turn the light off when the memory is erased?



Jan 13, 2012 at 11:08 AM
Avatar
HMAC300
  • ✓Experienced Mechanic
  • 48,601 POSTS
getting no codes could be a problem with the aldl or connection in it. It could also be a bad computer. i'd have it checked at another shop. it may be aground issue as well.
Jan 13, 2012 at 3:18 PM
Add a reply
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.

Frequently Asked Problems for This Vehicle