CHECK ENGINE LIGHT IS WILL NOT GO OFF

JDOOLEY

MEMBER
1999 HONDA CIVIC
17,500 MILES

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?

4 Replies

RASMATAZ

MECHANIC
75,992 POSTS

The CEL should stay on when key is in run position, should disappear when engine starts-problem here could be the wiring or the computer-

Was this

answer

helpful?

Yes

No

Friday, January 13th, 2012 AT 6:14 PM

JDOOLEY

MEMBER
3 POSTS

Don't know what you mean by "the CEL should stay on"?

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. Would a bad computer report that trouble code and turn on the light? And if it reports trouble codes, would it be BAD?