Check Engine light but no code

[lovemonkeysd]

I had a strange occurrence: My Check Engine light came on while slowing down for a stop, but when I tried to get the code by connecting a wire between 'A' and 'B' of the ALDL I only got the '12' code indicating diagnostic mode. I let it flash '12' about 8 times just to make sure I didn't miss the real code.

Has anybody else has a similar problem?

I have a 1990 Esprit SE.

Is this an indicator of my ECM going out and does anyone know the ECM part number?

Thanks,
Dan

[grungex]

I had a strange occurrence: My Check Engine light came on while slowing down for a stop, but when I tried to get the code by connecting a wire between 'A' and 'B' of the ALDL I only got the '12' code indicating diagnostic mode.

It's more likely that the engine was about to stall, or the battery voltage dropped. Check your alternator belt to be sure it's not loose. Did it just happen the one time?

Cheers,
Sanj

[lovemonkeysd]

It's happened twice. The first time the check engine light came on and it actually stalled at a stoplight. The second time only the light came on. I checked my belts and they are fine; not loose, not too tight. Any ideas?

Thanks,
Dan

[swedishsurgeon]

Dan,
I have to go with Sanj on this one. If the car is running fine and hasn't stalled again chances are the battery voltage is down which will cause this problem.
Is the battery original? Most do not hold up this long but I have seen {and had} some that will. I would do a battery load test and charging systems check which requires a special tester that can be performed by a shop of your choice. Or go to your local autoparts store and get a battery hydrometer to check the cell strength. A good reading is 1275 or higher...
any cell lower than that I would replace the battery. After a good charge, remove the surface charge by turning the lights on for a minute or two will take care of that.
Cheers,
Robert
'87 TE hci

[lovemonkeysd]

Thanks for the info. I'm willing to bet my battery is original, but I'm not sure. I'll check the strength, but I'll probably just get a new one because that's easy. On a positive note, I went for a drive this weekend and didn't have any problems!

Thanks!
Dan

[Doors]

Hi Dan,

My engine light has come on twice in my 99 GT3 in the first week of ownership - I thought, Bl***y Hell - what have I got myself into - just got the car and the engines a goner - but it hasn't come on since (a month now) - so fingers crossed whatever it was has magically cured itself!
Doros.

[swedishsurgeon]

Hello Doros,
I'm falling behind here... you had a battery light which was on but went out. When the brushes in the alternator get low it will do this. Do you have a lot of miles on the car? Have the battery load tested with a carbon pile tester and then the alternator. When the brushes get worn low, the light will come on, but then they pick up a contact sometimes making the connection in wich the light will go out. Have your charging system checked out.
Cheers,
Robert

[lotusman]

What does your volt meter say? The voltage must be over 13.5 v at all times. If not the battery will eventually run out. Most of the dash warning lights will come on at that time. I have put several voltage regulators on my alternator and other older cars.

Also because our batteries are not next to the engine like most cars they will run longer, generally, than the 48 or 60 months usually stated.

lotusman
'89 non-SE