"93 coupe. While out driving the "service engine soon" light comes on and off a few times. What's up with this......Car seems to run really well....engine temp 196.....new mobil 1 in the late fall???? What's my next step???? THANKS

 

Your car is throwing a code. Get a code reader and find out what,,,,,,,

 

Under the driver's side knee bolster, forward right above the gas pedal, is a small black connector. 16-pin, may have a cover on it that says DIAGNOSTIC on it.

Pull the cover, get a paper clip and straighten it out, then bend it into a U. Push one end of the wire into the topmost, rightmost hole. Push the other end into the hole next to it to the left. These are the A-B links.

Insert your key, and turn it to the RUN position but don't start the car. Be prepared to jump as the fans roar to life. Watch the SES light on the dash.

The first code should be a Code 12. The SES light will blink in sequence -

BLINK....BLINKBLINK. BLINK...BLINKBLINK. It will report code 12 three times. If there are no stored codes, it will just keep flashing code 12.

If there are stored codes, then after the code 12s, it will move on to the stored codes. For example -

Code 32 will look like this - BLINK,BLINK,BLINK...BLINK,BLINK.

:D :D

After you pull the code, come back and tell us what you found.

Also, you can pull historical codes from the CCM. CCM codes are easier to read, because they display on the central LCD screen in a '93.

To display CCM codes, you use your wire to jumper socket A and socket G. Socket A is the topmost, rightmost socket, and Socket G is the lowermost, leftmost socket. Same procedure - jumper A to G, insert key, turn to run but do not start.

The CCM codes will display on the speedometer. The display will clear, then show "1." , then display a "C12". It will poceed through "1.1" and display CCM codes, go to "4.1" and display ECM codes, then go to "9.1" and display ABS codes. CCM codes are either C or H, for current or historical. ECM codes are always H. ABS codes are always H.

Thank you very much to Gordon Killebrew for teaching a group of us about CCM codes at the Cruise-In.

 

Matt,
Thanks for your great explaination and how to pull the code. As usual you guys really do know it all. Anyway, the code that blinked out was a 64. Now what is a 64, and now what should I do????
Thank to all again.

 

I believe the 64 is the right bank O2 sensor circuit. Make sure the wire is not pinched, burned, disconnected ...... I would also reset Mr. ECM and see if it sets again. If you still have it O2 sensors could be in order.

V

 

.....where am I looking for this pinched, burned out or disconnected wire??

 

Code 64 means that your system is lean. The o2 sensor in this case is on the exh. pipe below the header. It could be lean due to a bad MAP sensor. Disconnect the MAP, clear the code on the ECM and see if it resets the code. If so then replace the o2 sensor. If not , I'd suspect the MAP.


[Modified by ittlfly, 11:51 AM 6/2/2002]

 

Put the car up on ramps or jackstands. You'll have to be able to get yourself under the car on the right side and left side just behind the front wheels, with enough room to do some looking around and wire-wiggling.

The O2 sensor and the knock sensor harness splits out of a wire loom below/between the headers and oil pan, and the 02 sensor is screwed into the exhaust header.

I like the idea of resetting the codes and disconnecting the MAF (Small black plastic matchbox-sized gadget at the front/right/top of the manifold, just behind the throttle body, next to the TP sensor. Easiest way to reset the codes is to disconnect the battery for at least thirty seconds. At least, I think that resets the codes...

It could be an actual lean condition, of course, with a clogged or dead injector, failing fuel pump, clogged fuel filter - engine management is demanding, and looking for, a certain amount of fuel and not getting it...