I've been chasing I believe an ABS issue for over a year in this truck. It started as a non existent issue that was just annoying. Rougher highway, bridge bumps ect would disengage the cruise but never had a fault code so no where to go with it. I assumed it was a wheel speed issue shutting off cruise but it wouldn't fault for it. Resume cruise and fine until the next bump, nothing more than annoying really.

Finally this past month it started setting a fault, LR speed sensor erratic. For some reason when scanning (AlfaOBD) in the ABS module I have two P0037 faults LR Erratic. They both read the same not sure if that's an ALFA glitch or if I should try a different scanner and see if its actually a different code.

I replaced the sensor (standard motor products, rockauto), it had some marring and scratching so I was optimistic I had repaired the issue. Connector was clean no corrosion. Drove maybe 75 miles no issues. Came up on a hidden stop sign and really stomped the brakes, almost felt like a hesitation for split second in the braking, popped abs fault and stopped like normal. Now I clear the code, in a mile or two its back, same LR erratic code. Yesterday I have a 200 mile trip, was dreading no cruise so reset codes, the usual 2 miles or less it was back. On the return trip I tried once more to reset, this time the codes stayed away slightly longer, but I noticed my speedometer reading exactly half my actual, cruise working. In maybe 5 miles it set warning service ABS system on dash but only the TC light came on, cruise disabled. Drove this way probably 30 miles, when the ABS light finally came on along with park sense disabled, which BTW why does park sense shut off with an ABS fault, its not controlling the brakes? (wish it would). With this the speedometer corrected to actual MPH and drove the rest of the way. Same LR erratic code.

Lots of information, my question is, I think this truck falls in the era of the impossible to get ABS module that was plaguing the nation while the other plague was happening. I only raise question of the module due to the braking hesitation, and the strange setting of the fault codes, with incorrect speed and no fault. Where does one start to diag if its module issue or sensor/wiring. Did these trucks have a problem spot for wiring damage? I have inspected but not seeing anything of concern, without stripping all the loom. Of course there's the section behind the fuel tank, that's much harder to access. I know with the stretch my wiring is no necessarily in the factory location anymore, the the 160k miles before hand could have started damage that's finally coming out, or possibly post op damage.

 

I think the left FRONT sensor is what feeds the speedo/cruise control.

 

I'll Check into it, I will correct its probably C0037 not P0037 and I see with some googling that there's a second FMI people are posting with fault C0037 so I'm wondering if that's why I have multiple C0037 faults, I'm not seeing the FMI that follows.

I'll scan again report back.

 

My other scanner, though being an ABS capable unit, and can read ABS on my 06, apparently can't read ABS on this truck, so I have no backup. Alfa seems unable to give me anymore information.

 

Yeah, protocols keep changing, pretty much at random.... which makes finding a scanner that does all the tricks you want it to, is difficult, unless you wanna spend north of 5K for a job shop level scanner... (which won't be tax deductible for you..... probably.)

 

Yea, i remember the 2nd gen kelsey hayes systems, people be like oh i got p0300, no you have a generic speed fault, get a scanner that will read it. "I do have an abs scanner" not the right one lol.

 

Now I have c006c, stability control verification mismatched or something like that, I'm guessing the speedometer issue, and probably why the faults set different.

Cannot locate an GMI indicator though so for now I think I'm going to chase the wiring for LR sensor

 

We finally got a minute to work on it. Start from point A, checked the new sensor. Condition it still looked new, except it had an afro of metallic on it. Cleaned it reinstalled and cleared codes. Road tested, so far seems ok, brakes function normal, speedometer works normal. I'm not sure the source of the metal, I hear no grinding sounds. I replaced parking shoes last spring, maybe the shoes have to much metallic in them but the passenger side hasn't bothered at all so I'm not sure. Ill see how long until it happens again.

 

Well have a few morning errands abs light came back on, didn't have my scanner with to check it and then forgot about it. Parked overnight and the light is gone again, haven't driven very far so we'll see