electrical problem/On Board Diagnstics (OBD) plug problem

[eksz]

The check engine light was on in my 94 ES. I decided to check the engine codes. FYI: To read codes on a 94 you have to ground the On Board Diagnstics (OBD) plug at position #1, and then count how many times the idiot lights flashes.

While trying to check the codes I accidentially grounded position #16 (12V +) plug position on my OBD plug when I should have grounded plug position #1.

Now my radio is dead, clock is dead, the electric door locks on the driver's side work only if the ignition is turned on (passenger side works fine with or without the ignition turned on) and the beeper to remind you to use your seat belt is making a strange sound until the seat belt is secured. Car runs fine and yes the check engine light is still on. :cry:

Fuses seem okay. Suggestions as to what to else check?

[bronxbombr]

maybe you did somthing to the ecu.

[mitsufan]

I assume you checked the IOD fuses under the hood (radio and interior lights)? I grounded mine too accidently when I first got my car and did not know too much about it and had the same problems: radio clock dome buzzer not working. I looked at all the fuses under the dash and all were fine, but forgot about that the radio fuse was under the hood. So i found that the interior light and radio fuse (in the yellow holder) were blown and replaced them.

[bmxmike]

Id say it would be a fuse cause those other things arnt really controlled by the ecu those are more controlled by switches and motors. Now if some of your sensors arnt working now then id say its your ecu but id say look under the hood and check your fuses

[eksz]

Mitsufan, bmxmike,
You were right, it was the fuse in the yellow holder in the under the hood fuse block. I checked all the fuses under the dash. I also checked the 15 amp radio fuse (in the yellow holder) in the under hood fuse block. All were fine. I didn't check the 10 amp interior fuse (also in the yellow holder) right next to it. Based upon your postings I went back and checked both fuses in the yellow holder. The 10 amp was blown!! Guess the two fuses work together so it makes sense the 10 amp blew first.

Well we now now know that grounding position #16 (12+) of the OBD plug blows the 10 amp fuse in the yellow plastic double fuse holder under the hood.

FYI: I also found the electrical plug at the volume air flow sensor had worked itself loose. I reconnected it and now everything is back working. I disconnected the negative battery cable to clear the codes and the CEL light is finally out. Funy thing is the car was still running good all through this.

Thanks all for the assist, jjj

[mitsufan]

No problem. Glad I could help you :D

[eksz]

This the OBD2 plug with a few of the position indicated. Our 94 and 95 cars are equipped with this 16 pin OBD2 style connector but have OBD1 type diagnostics which means you can't use an OBD2 code reader to read the error codes. Instead on our 94 & 95 models you ground out position #1 and count how many times the Check Engine Light (CEL) flashes to determine why your CEL is on. (Haynes manual chapter 6, page 6-5 for details),

pin 16 +12v power
pin 5 ground
pin 9 8192 baud serial data
Pin 1 ground out to determine error codes on 94 & 95's

Hope this helps, jjj

[mitsufan]

Good find!