OBD 1 Fault Codes
 

Does anyone have a chart of fault codes for the OBD 1 diagnostic system? I'm using the blink codes of the check engine light and need to know for sure what a 15 means. The Bentley book shows throttle potentiometer but that seems unrelated to my stall issue.
Thanks!
James S.

I believe 15 relates to Idle Speed Contact, either failed or working intermittantly, if it is an engine fault code. I asume this is the Idle Position mico switch on the left side of the! throttle body linkage. Exactly what car do you have?

Mine is a 1995 911 (993). Early version with OBD 1 pins.

Thanks Paperboy! Let me give you the whole situation and see if you have any ideas. My 1995 993 starts and runs strong until (with a/c on and stop and go driving) it gets hot. The temp gauge is just at normal. Then the car stalls and will not restart until it cools. I changed out the DME relay and that did not change the stall, only cooling and then a restart.

I think the micro switch relates to 964, potentiometer to 993. No expert, you might have checked but does the throttle body mechanism move freely? If that is the case I believe you can reset things by disconnecting the battery, check that the throttle is closed and restart the engine. The ECU will read this position and log this as Throttle Closed position. Any way of removing the potentiometer and measure it or measuring it in place ?

I assume that it works like a lot of other sensors on these cars. It is supplied with 5 volts and sensor position gives 0- 5 volts out which then the ECU translates to a throttle opening degree.
I know electric components can work OK when cold but then start missreading when hot due to expansion, especially if worn.

I would also like to know what the codes are for the 964 and 964 Turbo OBD1 cars. Someone gotta have a list.

Thanks for your help

The Bentley has a list of some of the codes, 1-5 is not among that list.

Mine flashes 1-5 as well. However, the motor is in a kit car, and a number of things (air injection, AC, heat, blowers, speedometer, etc) are not connected.

A couple of places I have found that list some trouble codes, no idea if they are correct:
https://rennlist.com/forums/993-forum/995719-fault-codes-on-95-993-obdi.htmlhttps://www.troublecodes.net/porsche/