Been searching but cant find info on how to manually check the check engine light code on my 93 gts without the bosche hammer. Please help.
Thanks,
James

 

This only works if you have the stock chips, but the way you check it is to mash the gas pedal all the way, then turn the ignition to on (obviously do not start the engine) and wait 3-5 seconds. The CEL should flash out any codes it has stored.

 

But Andrew, the 'mash' would be more fun with the engine running...

 

James-

There's a section of the '91 Tech Info document that has the CEL test procedure. Here are the relevant pages:

https://webfiles.uci.edu/redwards/pu...o%209-8-10.pdf

 

Man, what an archaic code display system. Probably seemed hi-tech at the time.

Are the procedure/codes different for later GTS model years, Rob? Your reference indicates 928 S4/GT.

 

Yep, morse-code-crude, but it works without any expensive tools.

Honestly I have no idea whether the system is the same from '91 on, or not. I would assume so, unless there are additional codes due to the dynamic kickdown thing in '94. Don't ever recall seeing any such TSB or update to that effect anywhere in the Morehouse CD's.

 

Thanks guys. I will give it a try.
James

 

Just throwing this out there will this work in my 90 964 c2 my car is running good but nice to check just the same and maybe find and fix before a problem.

 

Dunno. Ask the 964 forum

 

You are correct. At the time, most other cars had no capability by themselves to display any codes at all. Some other cars had to revert to crossing pins in a diagnostic connector to achieve the same display. The 928 was much simpler in that respect.

Dan
'91 928GT S/C 475hp/460lb.ft

 

This was the precursor to the OBDII, or so I'm told. I think it's kinda cool you can have the car tell you what the problem is - even if it's old-tech.