C2 Check Engine Light
 

Hello all, on my '91 C2, the red Check Engine warning light comes on sporadically, and when it does, i note the car runs poorer- hesitation, lack of power, rough idling, and even stalling. Sometimes it will go away on its own and everything is fine until it happens again. What is going on, and is there an easy fix?

Thanks,

Wilkie

get a code reader. the basic ones can be had for $100 then you can tell us what's causing it.

Hi Wilkie - as the above member pointed out, a code reader is the way to go to assist with the diagnosis. We have a deal with 25% OFF our Schwaben Pro Tool. Link below. Let us know if you have any questions.

https://www.pelicanparts.com/catalog/shopcart/TOOL/POR_TOOL_STTOL3-detail.htm

You sure those tools will read a round connector odb1 interface in the 964 ?

Wilkie you’ll need the scantool interface, durameteic, hammer, hammer clone, or early piwis to read the codes. And it likely won’t tell you much. Odb1 interface and error codes are very limited.

If you’re in la area I’ll do it for you pm me.

I use this one.
https://www.bergvillfx.com/index.php/products/t-obd-diagnostics-for-porsche-968-964-and-993.html

Can you not do the ignition to on and hold gas pedal for 3-5 seconds and read the flashes?

Yeah, i have that one, it's software is clunky but it works well. does almost everything the hammer does


worth a try. my 91 that didn't work right?!

My 964 had sporadic problems like this when I had a bad battery ground cable and a bad ground strap connection elsewhere. I have the Durametric software and it was showing no problems when the problem existed.

Two other items:
1) you could have a broken distributor drive belt. To test remove the coil wire to the primary distributor ,closest to the center cooling fan, then try to start the car. If it runs, the belt is good, no need to remove the caps
2) There was an update to the AFM wiring harness plug. The original was straight in to the AFM with standard connectors. The harness would press on the upper sound pad and intermittently create a poor connection. The update uses a 90 degrees connector and boot, with gold plated connectors. Part #000.043.202.74 retail $24.62
If you reach over the top of the AFM you can feel if the connector is straight or 90.
And also NO most OBD testers will not work on OBD 1. Porsche 9288 "hammer" or System tester 2 with the OBD1 adaptor as sperx mentioned

Thanks for the tips, everyone. I'll try the suggested trouble shooting, and if nothing works I'll have to track down a code reader that'll work on a '91.