[Greenvy]

I had an issue with the car jerking a bit when starting from stop (sometimes). Didn't floor the accelerator or anything - just regular driving. The car service light (car with ! sign in the middle) comes on and "Propulsion Power reduced" message displays too. The transmission stops functioning in L mode and behaves like D mode. This is on a 2017 Bolt LT with 22k miles.

This started happening a month ago and the dealer said that the recent recalls should resolve it (I hadn't gone in for Recalls yet). When I got the car back, he said that that recalls indicated that a software upgrade included in the recall should resolve it.

The issue is that the problem is still happening. It happens at any time when starting from a stop sign/light. The service light does go away in a day or two when it doesn't jerk but sometimes it takes a couple of days. Took it too the dealer again today.

His update is that "the code indicates that the transmission speed sensor and the wheel speed sensor have a difference greater than 12 mph". They are waiting for GM to tell them how to resolve it.

Not clear how long this will take at this time ...

 

[XJ12]

what could wrong with the resolver? someone just speculated that on the weber video.

supposed to have a self learning feature on the resolver.

 

[GJETSON]

This started happening a month ago and the dealer said that the recent recalls should resolve it (I hadn't gone in for Recalls yet).

What recent recall!!?? I check for recalls at least once a week. As far as I know there has not been a recall since the second traction battery software update, way back in May.

 

[Sean Nelson]

What recent recall!!?? I check for recalls at least once a week. As far as I know there has not been a recall since the second traction battery software update, way back in May.

Recalls can be issued for specific VIN ranges that might not include your car.

 

[Bolt Action]

Ah, I read the title of the thread, and thought it was about people like me who like to gun the 200 HP electric motor, supplying 2500 newton meters of torque to the axle.

 

[Greenvy]

The recall indicated above was the summer recall itself. I didn't get it fixed earlier.

Anyway, the dealer has said that it was too long ago for them to accurately diagnose the issue. They have a case open with GM. They have released the car back to me and asked me to bring it in again when it happens again.

Happens every week. So, it should be back pretty quick.

 

[Heather Manelski]

Having similar any update?

 

[mrclean92124]

OK, i've got the same situation here... This is what I've found....I'm ready to open her up now...
C0506 Generic
C0507 Generic
P215B *** Right front speed sensor mismatch
P25A2 Generic propulsion issue

So here goes the theory I already visually inspected the ABS sensor cable (wheel speed) and it looks fine, no critter chew marks or anything. I saw a video on youtube where a guy replaced a wheel bearing on low milage Volt (<90k) for speed sensor issue, and the speed sensor 'ring' that generates the signal to the ABS sensor was broken out due to rust on the inner bearing. It seems this is a design flaw, if moisture/salt gets in there the tiny thin fragile speed sensor ring, breaks and falls down in pieces, then, the sensor throws the big error...

Few ways of troubleshooting this: This video is for a different P1225 error, but shows how the system works.

1. switch the sensors from Left To Right, etc. and see if the error changes sides. If it does, you know you have a bad cable, if it stays same side, you have a bad bearing.
2. pull problem cable connector and read voltage while spinning wheel, it should bounce V in regular pace (see video)
3. I'm going to pull sensor and look directly at backside wheel bearing with an endoscope. 8)

 

[XJ12]

1. switch the sensors from Left To Right, etc. and see if the error changes sides. If it does, you know you have a bad cable, if it stays same side, you have a bad bearing.
2. pull problem cable connector and read voltage while spinning wheel, it should bounce V in regular pace (see video)
3. I'm going to pull sensor and look directly at backside wheel bearing with an endoscope. 8)

Welcome to the forum. Let us know what you find. Very interesting.

 

[mrclean92124]

OK, i got it apart, I used endoscope to look inside sensor hole and definitely saw a problem. I thought it was the signal ring. But surprise when i pulled it I found it was a spacer ring between base of drive shaft spline and inner bearing. It was ripped open and obviously wrecking the ABS signal. I found the part number online, and I believe this is a dealer item, I will pick up Monday. Online it's $8.00 from Amazon. The inner bearing race is a bit scuffed up but nothing serious. Lucky this didn't rip up the plastic signal ring. This was a hard part number to track down, took me 3 Google sessions to get it.

When I get it back together I will test and see if the codes clear. I believe this goes under the 'clicking wheel' issue. We didn't hear much of a click but I could definitely see how this could cause one.

BTW for those performing this repair the Caliper assembly bolts were a #%*# to break loose. They are 21mm and the lower strut bolts are in the way. I had to pick up these swivel impact sockets from Harbor Freight to get a good angle on them. Good news, nothing was rusted together. If you do have a rusty hub, the trick is to leave the 3 hub bolts 1/2 inch backed out, then tap the ends with a hammer to push/break the hub loose.

GM Driveshaft Washer - 11611965

 

[GregBrew]

Wow! I probably wouldn't have attempted this on my own. You're a better man than I.

Now that you've done it, I'd probably try, too.

Thanks!

 

[mrclean92124]

Watch the YouTube video is shot on except two additional tips I give above about rust and swivel socket set. Also you will need 2 feet of 1" PVC pipe for leverage on your 1/2" ratchet. The higher up you lift the car the more room you have to lever those bolts off. If you aren't a strong man you may need help on those.

 

[mrclean92124]

OK got everything replaced, but still throwing code. Used green scrub pad to buff the inner race of hub bearing, looks good, little bearing grease on splines and inner race where it contacts washer, after cleaning carefully with plastic tooth brush....

I noticed the wheel speed sensor had a groove cut from the broken washer. There should be no groove of any kind in that sensor...my delco replacement has no groove... I will change that out next and I'm 100% sure the code will clear.

As an added bonus, download this PDF, it gives ALL the codes and how the PCM generates the codes, what tests they run, and what codes mean...

This is a really good find: 18OBDG02 Hybrid Diagnostics.pdf

 

[Toyotiac]

That link appears to be the code library for a (Gen 2 ?) Volt. Are Bolt codes all there as well?

 

[mrclean92124]

No idea im sure there are... Google is your friend. 8)

 

[mrclean92124]

Final status... code cleared...$18.00 spent for a wager and sensor... Happy wife 8)