(see also here.)

After replacing and cleaning grounding points G401 and G402 (the original studs broke off) I received ABS and traction control warning + DTC C1242 ("pump motor circuit open").

1. Today my Tech 2 scanner arrived and it says "BPMV Relay is Off. Repair as necessary before continuing".



2. The data list says ABS and Traction Control fail and are inactive.



3. Solenoid relay commander and feedback are off. Pump motor relay commander and feedback are also off.



4. Other variables:




5. I wanted to test the pump...



6. But the Tech 2 didn't allow me to do that:



7. Same with the Solenoid tests. I just chose the first one...



8. ... got this screen:



9. And also here I was not allowed to do the test (I chose "on"). First the problem (relay for the BPMV motor) has to be solved...



10. All ABS sensors seem to work. This picture was (obviously) taken while driving.



11. In this post, Bill Curlee advised me to do this:

So that is the first thing I will do. After that I will let you guys know what happened.

 

Good information in these topics:

https://www.corvetteforum.com/forums...1242-code.html

https://www.corvetteforum.com/forums...c-c1243-h.html

https://www.corvetteforum.com/forums...r-stalled.html

https://www.corvetteforum.com/forums...-and-bpmv.html

https://www.corvetteforum.com/forums...e-to-ebcm.html

https://www.corvetteforum.com/forums...s-weekend.html

 

Thanks for all this info.

 

Issue has been solved! Update with pics and vid later tonight..!

Thanks for your reply... I am learning so much from this forum that the least I can do is add a bit more info. My problem might help others..

 

12. Taking up Bill Curlee's advice, I measured the resistance. This is difficult to do on your own on a 1997/1998-model, as the frame grounding point is not in sight when touching the motor ground. So I asked my girlfriend to help me.

The stud and nut were quite corroded and the multimeter wouldn't easily stabilize. Two measurements: when checking the inner nut (the one Bill warned should not be rotated) I got around 5 ohm. When I checked the cable I got 0.0 ohm.

Then, for the sake of exclusion, I connected an external electrical wire from motor ground to frame ground. And guess what... no more ABS / Traction control warning lights or messages. Apparently somewhere in the grounding cable a breach has occurred. Not sure how that could happen, I have been very careful while cleaning the G402 ground and no visible damage is seen. The cable was never bent.

Anyway I decided to simply install this new cable (after cleaning the stud without effect).

On the next picture, taken from behind the car, the stud can be seen as it was.



13. This cable made the error messages go away:



14. I used a liberal amount of WD40 on the nut, then loosened it - taking good care to keep the 'internal' nut from moving. Having cleaned it, I first placed the new ringlet and over that the old ringlet (what else to do with it). Nut was cleaned and repositioned.



15. The frame ground now has two connectors as well. I hid the new grounding cable as much within the harness tube as I could.



16. Now the fun bit: testing. This is a Tech 2 test. Note that the BPMV motor is actuated only for very short time. Please click this link and press "play":

https://www.flickr.com/photos/606877...etaken-public/

17. Getting on the street now. ABS works perfectly

https://www.flickr.com/photos/606877...etaken-public/

So thank you all for watching. Very happy to have solved this so easily and swiftly. And good to have learned that the ABS module should be 'exercised' on a regular basis. Let's wait for the rain....

 

Glad you got this one fixed. I posted some info on the passenger seat Thread a few minutes ago for you.

 

Thanks 8Vette7 and Dadaroo, yes I'm very glad this was solved so quickly.

Coming back to the passenger seat issue in a few moments