Vehicle: 1995 C2500 (8600gvwr) with 4WAL.
Issue: Air trapped in ABS module, cannot bleed via scanner (Snap-On Solus Pro with ver. 17.2 software), DTCs present, can't bleed with DTC's present, scanner displays 0 codes, jumping terminals A & H displays codes.
Codes:
Code 68 - Locked motor or shorted motor circuit in BPMV - sets ABS to OFF
Code 73 - BPMV memory error - sets ABS to OFF
Code 86 - Shorted ABS indicator lamp - sets ABS to ON
When I replaced my brake lines last year I foolishly let air into the system. At the time I did not think much of it because I had a snappy, surely I could bleed it. I attempted to bleed the system (November 2023) but the scanner would not complete the test. When checking the scanner for DCTs there are 0 present or stored. After that I took it to the dealer and they were not able to resolve it. All they did was say "code 68 can't bleed." I thought they would have success with one of their Tech2 scanners, no further diagnosis was performed.
Flash forward to today. I need to get this fixed by 4/15 so I can start driving it. I began looking at 68 first since that was all I had initially. I have 12v power at the 2 pin connector for the BPMV. I noticed that my ABS light was not on, so I diagnosed this - broken bulb. Replaced that and the light follows "normal" bulb check routine. Key on, ABS light turns on and shuts off after 2 seconds. The FSM states that certain DTCs may not trigger the ABS light to stay on. I think the DTCs that set the ABS to OFF would keep the light on.
I will try to manually clear the DTCs tomorrow via the ALDL port without the scanneer. I need to get my battery on a charger over night.
Attached are pages from the FSM with relevant information. Any help is appreciated. I would prefer to keep this system in place. I've also tried the bleeding procedure via pressing the plunger on the unit and that didn't help.
Attachments: Code list, circuit diagram, 67-68 description, 67-68 diag steps. The remainder are in post #2
Issue: Air trapped in ABS module, cannot bleed via scanner (Snap-On Solus Pro with ver. 17.2 software), DTCs present, can't bleed with DTC's present, scanner displays 0 codes, jumping terminals A & H displays codes.
Codes:
Code 68 - Locked motor or shorted motor circuit in BPMV - sets ABS to OFF
Code 73 - BPMV memory error - sets ABS to OFF
Code 86 - Shorted ABS indicator lamp - sets ABS to ON
When I replaced my brake lines last year I foolishly let air into the system. At the time I did not think much of it because I had a snappy, surely I could bleed it. I attempted to bleed the system (November 2023) but the scanner would not complete the test. When checking the scanner for DCTs there are 0 present or stored. After that I took it to the dealer and they were not able to resolve it. All they did was say "code 68 can't bleed." I thought they would have success with one of their Tech2 scanners, no further diagnosis was performed.
Flash forward to today. I need to get this fixed by 4/15 so I can start driving it. I began looking at 68 first since that was all I had initially. I have 12v power at the 2 pin connector for the BPMV. I noticed that my ABS light was not on, so I diagnosed this - broken bulb. Replaced that and the light follows "normal" bulb check routine. Key on, ABS light turns on and shuts off after 2 seconds. The FSM states that certain DTCs may not trigger the ABS light to stay on. I think the DTCs that set the ABS to OFF would keep the light on.
I will try to manually clear the DTCs tomorrow via the ALDL port without the scanneer. I need to get my battery on a charger over night.
Attached are pages from the FSM with relevant information. Any help is appreciated. I would prefer to keep this system in place. I've also tried the bleeding procedure via pressing the plunger on the unit and that didn't help.
Attachments: Code list, circuit diagram, 67-68 description, 67-68 diag steps. The remainder are in post #2