[Pigwich]

Anyone seen this before?

View attachment 30368 View attachment 30367

Yeah on practically every car I've ever driven in Maine growing up. It's the salt and sand. Seems sorta fast for a 2017, but the winters are horrible, as you are no doubt aware, and it depends on what your town puts down too. Some towns use that brine solution, I have no idea what that does to cars long term, maybe it's better than rock salt? Or worse?

Another weird thing to wonder about is that perhaps everything stays wetter longer because the brakes don't normally heat up during use. Hard saying not knowing. Fact is, Maine winters have always eaten cars. Sorry. At least they're cheap parts....

 

[btm]

It looks like it's this process (the vid is for an Equinox, but likely the same for the Bolt).

So good times and bad times.

The non-scan tool EPB service mode steps I listed above didn't seem to do anything. I tried in my '16 Volt too, didn't do anything special, nothing on the DIC or no particularly different sounds than just the parking break releasing. I have an OBDLink MX+, but while that app does have some model specific support it's mostly codes for different modules. It doesn't really have any bidirectional support. I already have a Drewtech MongoosePro cable though, so I ultimately just used GDS2. The screen in the video for the Launch bi-directional scan tool looks like the same screen in GDS2 but with a different name.

A MongoosePro is $500 and GDS2 is $57 for 3 days. But there's a lot of finicky software involved. I work in the computer industry, so I didn't really mind. But this is a bad path if computers/software make you mad. I hadn't seen those chinese Launch tools before that Rick CH linked to in that youtube video. They have a ton of models, and the one website claims it ships from the US. Some are on ebay/amazon. Looks like the CRP129 is and is $189 on the website, it says it will do an "EPB Reset," the cheapest I see that lists that. But that's probably different than the $864 X431V from the video that has the brake calibration option.

I had a momentarily brilliant and then terrible idea. I was thinking about pulling the piston on the good caliper and cleaning it up. I had GDS2 push out the piston on the actuator on the bad caliper as a test. That worked, but when it got all the way out the EBCM flipped out. So I left the "good caliper" alone, but I'll come back to this.

The service manual says don't use air tools on anything. I'd also suggest not using any kind of impact/screw gun on the torx screws holding on the EPB actuator. Those like to strip.

The EPB actuators do appear to spin forever. Later when I was stuck I did hook one to 12V to check it. There are only 2 wires, so I presume the EBCM measures the current to determine when to stop engaging.

New rotors and pads. I got polymer coated rotors from NAPA. Probably not as good as GMs Ferritic Nitro-Carburizing (FNC) rotors but meh. I didn't want to give GM all the money for this thing. Got everything cleaned up.

With the EPB actuators removed, you can use a T30? torx hand tool to spin the piston in and out. My cousin passed by and said he uses channel locks on the end of the piston or something on another make, but this seems better. Clockwise with the T30 brings the piston back in, kinda slick, didn't need the regular brake caliper tool or any C-clamp silliness.

Everything back together and torqued, I went to GDS2 to do the parking brake calibration and the EBCM refused. It won't do anything, DTC 0561.43. The GM service manual says to reprogram the module, but SPS won't let you reprogram modules with the same calibration on 2017+ anymore. Presumably you can do it with a VCI or something from the Techline but I don't have access to that. I disconnected the battery for a while, tried different things in different orders, cleared all the DTCs, but the EBCM won't budge. I pulled the EPB actuators off, made sure the parking brakes were backed off with the T30, and drove to work. With the EBCM unhappy, the traction control and some other stuff are unhappy, and obviously no parking brake. But at least the car drives, in case I wanted to drive to a dealer.

The local dealers won't work on bolts/volts. The nearest that will work on them is about an hour. The dealer we purchased from is 2.5 hours away. I emailed a hail mary to the service manager there, but I think I'm going to have to buy a new EBCM online or schedule a visit with a dealer. I don't know any GM service techs personally though, so I'm worried they will just replace the EBCM at list price and not bother trying to talk to Techline to get it reprogramed.

 

[btm]

Out of curiosity - how is the rotor itself? I mean, the surface. Clean, smooth? Or rusty, channeled?

Ah I missed this. The RR was pretty smooth in the brake pad surface. The RL had one pad that was worn all the way down on half the pad (the other half was almost there). The rotor had some damage from that. I'm debating holding on to them and getting them turned since they're pretty new, but I really never end up doing that.

Both had a slight rust lip along the outer edge, maybe 1mm. If I think of it when I'm home I can grab a picture.

 

[btm]

 

[btm]

I've finally wrapped up this project. I've got some information to share that ultimately wasn't required but may be useful to someone in the future googling for issues.

ABS Control Module / Electronic Brake Control Module / EBCM - Replacement

This isn't the right way to do this, but it was the easy way to do this. GM's official directions are significantly longer and safer and all that.

The EBCM is under the coolant reservoir for the cabin heater, on the passenger side of the engine compartment. It's the thing with all the brake lines connected to it.

I ordered #42514365 from an online GM parts dealer. List is $404.47, I payed $237.44. My local dealers always charge me list price so meh. This is only the electronic part, does not including the modulator valve that the brake lines connect to. This comes with new bolts, rubber insulators, and cute little screw in plugs for the brake line ports to keep them clean.

First I disconnected the 12V battery and of course the charger was not plugged in. I did not remove the rear seat and pull the manual service disconnect / HV disconnect.

Under the hood, furthest to the passenger side, is the coolant heater control module. It is just to the left of the coolant container that is in the back of the engine compartment. I disconnected the orange HV cable from the CHCM at the High Power Distribution Module (HPDM), which is the large silver module on top in the middle with the most orange HV cables. I tucked the cable off to the side, leaving it connected to the CHCM.

If you remove the two bolts holding the coolant reservoir it drops down (which is also a nifty way to actually add fluid if you ever needed to). Moving the reservoir forward, I removed the rear coolant hose from it, and poured any coolant from that hose into another container. Then I poured out the back of the reservoir into another container. Finally I removed the reservoir from the bottom hose, and poured as much coolant from that hose into another container as I could.

The EBCM has two bolts that go through rubber insulators. There's a 3rd insulator on the bottom of the EBCM but no bolt. Loosen those two bolts up. The electrical connector has a usual safety latch to push down on, then a handle to pull to work the connector all the way out. Remove the 6 brake lines. Push the brake lines to the side and firmly pull up on the EBCM.

There were four special bolts to separate the valve module from the electronic portion. The replacement came with a little plastic prying tool to carefully separate the two. The replacement electronic module can be carefully pushed straight onto the valve module, then the included new bolts tightened up. It came with new insulators too, so I replaced all of them since I had them.

To install the new module I worked in back into place around brake lines and hoses and firmly pushed it down. Make sure the rubber insulator in the back that you can't see goes into the correct spot. Reconnect the brake lines, tighten everything up. After reconnecting the coolant reservoir, putting the coolant back in took some patience. I massaged the coolant hoses to get air out. There's probably still some air in the system and a proper way to get it out, but I haven't had an issue or looked into it.

With air now in the brake lines and the valve module, I used the special function in GDS2 to bleed it. This has you loosen up the bleeder screws one at a time and pump the brake pedal. You follow the instructions and it occasionally freaks you out by exercising the ABS valves loudly to get the air out. Pedal height was restored after I finished going around.

Then I used the SPS to program the new EBCM using the Mongoose Pro cable, which went fine.

Unfortunately, this didn't resolve any errors or issues I had. The DTC errors in GDS2 about the EEPROM were kind of red herring. Attempting to calibrate the parking brake using GDS2 still gave an error about "Out of range" and in addition to the "System Disabled Information Stored" error, I now had one reminding me that I had not calibrated yet.

Parking Brake Actuator Replacement

Since I had run out the driver side [rear] parking brake actuator, I figured it needed replacement. Sometimes I saw DTC codes about low or high current, and whatever I did it always seemed to be the passenger side actuator that did anything, if either did. I decided to buy two though, so I bought #13529269 for $42.79 each, list is $69.51. No local parts stores seemed to stock these which seemed a little odd, since my 2016 Volt has the same part too. One had an aftermarket part listed for like 4x the cost.

These came with new bolts and new gaskets. I didn't replace the gaskets, it looked too easy to damage their seat if I tried to ply them out and they're fine. Fortunately these are real simple to remove and replace, you can kind of do it without even jacking up the car. Most important thing is having a hand torx driver.

With both replaced, I went back into GDS2 and ran the parking brake calibration under the EBCM module, it quickly completed this time without error. I cleared the DTC codes on the EBCM module and for the first time since the beginning of this they stayed cleared. I turned off the car (it was in service mode) and turned it back on, now with no parking brake warnings or errors, and the parking brake switch worked normally.

All good again. Now to deal with that annoying 16-NA-183 shifter issue.

 

[stangbat]

I'm trying to wrap my head around this and I'd appreciate it if you could provide some clarification and answer some questions.

When you service the calipers, the EBCM needs to be reset, correct?

Resetting the module can't be done with any of the available simple OBD II tools. You attempted recalibration/resetting with other tools and were unsuccessful.

I assume with the correct tools it is possible to recalibrate the EBCM, but you chose to replace the module instead as the path of least resistance and bang for the buck?

Finally, do you know what action triggers the EBCM to require recalibration or it being reset? Is it when you push the piston back into the caliper it runs out further than the previous engagement and the software throws a code?

 

[PLP]

Nice write up.

Let me get it straight.
Replacing pads means all this work? Or could I replace them and drive to dealer to reset whatever needs to be done?
Or was it due to the caliper seized up?

 

[btm]

Most of this work was trial and error due to not being able to find any information handily at the time and not needed for brake work.

If you replace the rear pads, rotors, or calipers, there are 3 software steps. You may be able to avoid them. I've marked them below in this green text color. As long as you don't do anything odd to the EPB actuators (like I did), the worst case should be that you need to have to drive to a shop after to clear the codes/calibrate the parking brake, which any shop could do for you. If necessary, you can drive the car with the EPB actuators disconnected, which we did for a while.

1. Park the vehicle somewhere hard/flat as usual for service.
2. Disengage the parking brake using the switch in the vehicle, shut off the vehicle.
3. Optionally and ideally, use GDS2 or an OBDII tool that supports it to retract the EPB actuators into service mode.
   1. Do not extend the EPB actuator with software or the parking brake switch with the brake pads removed. This is how I caused myself problems.
4. Optionally, disconnect the 12V battery. This may help avoid needing to clear some DTC codes using a normal OBDII scanner later.
5. Jack the vehicle/chock the wheels/remove the wheels, etc.
6. If you did not have the software in step #3 to retract the EPB actuators:
   1. Pull back the red locking tab on the electrical connector of the EPB actuator
   2. Squeeze and pull back the electrical connector to remove
   3. Remove the two torx bolts by hand that fasten the EPB
   4. Pull the EPB off and set aside
   5. On the caliper is a small spindle/socket that the EPB engaged. Carefully, using a torx or allen bit that happens to fit, turn this clockwise to retract the rod that is inside the piston.
7. Do whatever traditional brake work you intend to do, e.g. compress the caliper with a clamp and install new pads. The parking brake rods must have been retracted by hand or by software before compressing the caliper pistons. This was step #3 or step #6.
8. If you removed the calipers, you're supposed to replace the bolts with new Torque To Yield (TTY) bolts. GM Part #11516330, 100Nm, described in an earlier post in this tread.
9. Once the brakes are reassembled, if you are not using software to adjust the EPB actuators (you did step #6 above), then turn the spindle/socket on the caliper where the EPB actuator attaches counter-clockwise until the rod pushes against the inside of the caliper.
10. Reinstall the EPB actuators if you removed them in step #6.
11. Reinstall wheels, remove jacks and chocks, etc.
12. Reconnect the 12V battery if you disconnected it.
13. Pump the brakes until the caliper pistons engage.
14. Optionally, use GDS2 or an OBDII tool that supports it to calibrate the parking brake.
15. Optionally, use GDS2 or an OBDII tool to clear any codes.
16. Engage/disengage the parking brake using the switch to confirm operation.

I don't know if you can avoid the three software steps, I'd have to do it all again. Perhaps if someone follows these steps later they could update us as to if they get to the end without any error codes.

There is a nice guide for a 2020 Camaro that is pretty accurate for the Bolt too, in retrospect.

I think the most important takeaway from my lessons is that the "out of range" errors appear to have meant to replace the EPB actuator.

 

[stangbat]

Thanks for the write up and link to the 2020 Camaro info. Based on what you've said I feel better if the rear pads ever need to be replaced or the calipers need work.

 

[sundog]

1. Do not extend the EPB actuator with software or the parking brake switch with the brake pads removed. This is how I caused myself problems....
   1. Optionally, disconnect the 12V battery.

Has anyone needed to change their pads on a Bolt due to "typical" driving? My recollection from the Nissan Leaf forum was that somebody asked "has anybody had to change their brake pads, ever?" and only one member had done so (simply because he liked a particular brand).

Would disconnecting the 12v battery before pulling the wheel assure that the parking brake doesn't accidentally engage/extend while the pads are out? Or maybe it has a capacitor somewhere...

 

[btm]

Has anyone needed to change their pads on a Bolt due to "typical" driving? My recollection from the Nissan Leaf forum was that somebody asked "has anybody had to change their brake pads, ever?" and only one member had done so (simply because he liked a particular brand).

Would disconnecting the 12v battery before pulling the wheel assure that the parking brake doesn't accidentally engage/extend while the pads are out? Or maybe it has a capacitor somewhere...

I wouldn't expect anyone would have pads that need to be changed due to normal wear yet. Even if you're not using L, the regenerative braking would be limiting brake pad use that they'd last more than 3 years. Besides our wonderful road salt in the north, eventually someone who drives aggressively is going to need new pads though.

I suppose there is the case of the feature that automatically engage the parking brake if you're on a steep incline, but you're not doing brake work on an incline. I'm sure that disconnecting the 12V battery would protect against that if one was concerned. I wouldn't be worried about the parking brake accidentally engaging with the vehicle off though.

 

[Sean Nelson]

I wouldn't be worried about the parking brake accidentally engaging with the vehicle off though.

You should. There was a post from someone who tried to tow his Bolt behind a motor home and the parking brakes came on because the computer thought the car was rolling (which it was, but...). This despite the car was, obviously, turned off.

As a result of that post I keep a 10mm wrench in the Bolt to disconnect the 12V battery and disable this function in case I ever need to get the car towed.

 

[btm]

You should. There was a post from someone who tried to tow his Bolt behind a motor home and the parking brakes came on because the computer thought the car was rolling (which it was, but...). This despite the car was, obviously, turned off.

I wouldn't be worried in this context. It's a static condition. Towing is completely different, besides the vehicle moving there will be changes in incline as well.