GM C3 qns..

[Craig Henry]

On Tue, 25 Jul 1995, Craig Pugsley wrote:

---/--- cut
 
> Also, should the 'check engine' light flash fault codes at engine startup
> or only when you bridge the ALDL connector? (This is my main question
> actually)
> 
> Cheers,
> Craig. 
> 
  The check engine light should  come on durring start-up only to verify 
the bulb is working.  To retrieve the trouble codes, you must turn the 
vehicle off, then turn the ignition on... do not start.  Once the 
ignition is on then bridge the diagnostic enable to ground.  The unit 
will then cycle through the codes, if any are stored.

Code 12 will flash 3x if everything is working properly followed by a pause, 
then the trouble code(s) will flash in sequence ... 3x each. After the 
trouble code(s) are displayed, if any, another code 12 will flash 3X to 
signify completion.

Do not start the vehicle with the diag. enabled and becareful, I don't 
accept any responsibility... as the pro's say :)

later
Craig