ABS fuse location

Good afternoon,

I attached a picture of the fuse locations for you for the ABS system.

what is the issue?

Roy

Thanks for the schematic. Not real easy to read. Any chance you could email a photo in higher resolution? I will use Facebook to send my email address. The issue is the ABS light stays on so I am interpreting that the ABS will not work until the problem is fixed. Is it correct that there are only two fuses in the ABS system? If so I will start checking the wheel sensors next.

I would first have the codes checked in the system instead of guessing the failure. A parts store can pull the codes for free.

https://www.2carpros.com/articles/abs-warning-light-on-easy-repair-guide

Let me know the codes and I can help narrow the area of failure.

No need to pull the fuses at all. They are good if the light is on.

Roy

Related question when replacing the sensor. 2015 Chevrolet Express 4500 ABS. Following your video. Traced problem to the sensor. To get to the sensor I need to pull the hub. Brake caliper mount bracket has 21mm bolts that are very tight (over 150 ft-lb). broke standard socket getting them loose. After I get the bolts off, what is the torques specs for Caliper mounting bracket bolts and spec for the Nuts that retain the outer hub (w/studs) to the hub through the rotor. Guessing 80-100Ft lbs. Also to get to the sensor one must remove the dust shield. The four 15mm bolts that hold the shield also hold the inner hub. What is torque spec on the inner hub retaining bolts?

Is this a front sensor or rear sensor?

Roy

Right Front sensor. The sensor cannot be pulled through the clearance between upright and splash-shield. Splash shield is clamped between Inner hub and the upright so needed to R&R the 4 retaining bolts. Learned that you must use 6 point socket due to how tight the 4 bolts are. Luckily, I was able to remove 3 of the 4 bolts but did damage the heads. 4th bolt was too tight so the 12 point socket I was using, spun on the head and damaged bolt head. Had to drill & grind the head off the bolt (about 3-hour job) Luckily, I didn't have to order the 4 bolts from Chevrolet as O'Riley's had Dorman 517-917 bolt set only $34.00.
Still need torque spec for caliper bracket and the nuts that retain the outer hub to the inner hub. I will collect pictures and post tomorrow.

Okay, the torque is 180 lbs.

Roy

No wonder I had problems.

Yep, tight little buggers.

Roy

Wonder why GM didn't use lock tight on these bolts like they did on the brake caliper bolts. A bigger issue is why they didn't provide enough clearance for the sensor to be replaced without having to separate the inner hub from the upright so you can pull the dust shield and then replace the sensor wire.. Even if I hadn't had problems with the heads getting messed up there would be no need to take more things apart if GM had just increased the clearance between the upright and the dust shield by about 1/8". Feel like writing to GM Tire and Wheel systems and asking "What were you thinking?' I plan on cutting the shield so if there is ever another sensor failure the 4 super tight bolts don't need to be touched.

Remember you talking about an engineer. They lack common sense.

Roy

Okay, making progress. Want to confirm torque specs on bolts A & B & C & D in attached pictures The A bolts are 0.50"dia w/metric head. I have a Gr8 spec sheet indicating 120 Ft lb. Given that I had to grind the head off one of the OE bolts because I could not loosen it and buy a set of 4 new bolts $35, I really don't want to mess up the new bolts. Also wondering about torque for Bolts B, C & D. I figure C are just good and hand tight as the similar pins were on my other GM vehicles. "D" is the same as lug nut spec. After all the work of replacing the bad sensor, I still get error code C0040. The new sensor is okay as I get AC voltage. So module is likely?

Okay.

A. 120 lbs.

B. 180 lbs.

C. 53 on the caliper bolts.

D. 180 lbs.

Before replacing the module, do the same test at the ABS module for the sensor. That will eliminate the wiring harness.

Roy

Thanks for the torque specs. Surprised the "D" is that high as the studs are just normal wheel lug studs. The ABS module on the c4500 is different than the module seen in other GM trucks (and well documented on YouTube). The module has 22 pin plug so need to learn which two are from the RF. The module is https://www.carid.com/acdelco/gm-original-equipment-electronic-brake-control-module-mpn-84055067.html
then I can check the sensor again. Looking at the module image it looks like I might be able to pull the module off the pump and solenoid body so I don't have to break into the break-lines. Look likes the module is attached with 4 bolts and silicone like the standard module. Won't be as easy as opening the other modules as seen on YouTube as the module is bolted and sealed directly to the pump which is bolted to the frame. If the wiring test confirms it is the module then just getting the old module off and cleaning the RTV shouldn't be that hard, just tedious. I will capture some photos to post to help others with C4500.

Okay.

Roy