C0055 dtc

[mike diesel]

Was out data logging my truck one afternoon and noticed I had an ABS code C0055 (rear wheel speed sensor, both wheels). I have no clue how long this code has been there but I know that it didn't used to be there.

As far as I can tell, the truck has zero issues even with this code on. Trans shifts perfect, speedo works and is accurate, no erradic movements either... The emergency brake light and ABS light ARE NOT on and never have been on since Ive owned the truck. ABS seems to work fine as well.

I checked the wiring from TCM to the sensor and all is good, no shorts or continuity to ground what so ever. Also ohmed the VSS and it reads 1362 ohms. From what I have read online, a brand new sensor has the exact same reading. So I'm assuming the sensor is fine.

I do believe the bushing in the t-case is worn out because even with a new slip yoke seal, it leaks oil and has flipped it all over under my truck. Would that worn out slip yoke bushing cause any abnormal play between the reluctant ring and VSS? The play in the slip yoke is minimal when pushing up on it. If you clear the code, it comes right back once you start driving.

Is it common for the reluctant ring in the t-case to come loose or be damaged?

Like I said earlier, I only noticed this code because I happened to scan it when I was out data logging one day. I first noticed it last week of april. Truck still runs and drive just dandy.

Would a funky vss reading have anything to do with the ECM cutting fuel through first gear then kicking the fuel on like the nitrous button was just pushed mid way through 2nd gear when you mash the pedal from a dead stop?

 

[AKlowriderZ71]

Pull the sensor out & check it for damage. With your bushing bad, it is possible for the tone ring to get too close & make contact with the sensor. This may or may not be your problem.

I believe burnouts/tire spin may also cause erratic speed sensor codes, because the EBCM sees the front & rear wheels going different speeds.

 

[mike diesel]

Pull the sensor out & check it for damage. With your bushing bad, it is possible for the tone ring to get too close & make contact with the sensor. This may or may not be your problem.

I believe burnouts/tire spin may also cause erratic speed sensor codes, because the EBCM sees the front & rear wheels going different speeds.

I didn't pull the sensor out this morning when ohming the wires but last time I changed the t-case fluid, I think I remember business end of the sensor having a scuff in it now that you mention it...found brand new one AC delco ones on ebay for $17 so I'm just going to order a new one for the hell of it.

 

[mike diesel]

I ordered a new VSS off of eBay for $16 bucks...Dealer wants $60. Going to dig Into it a little bit tomorrow and see what else I can find.

Most everything i find online about this code, peoples ABS light was on with this code present and the speedo had erratic movement as well as terrible shifting from the trans. Everything on my truck works perfectly fine.

We will see what I can find tomorrow, if everything looks good tomorrow then I will have to wait till thursday when the new sensor shows up to replace it.

Unfortunately I don't have any scanner that is capable of viewing real time ABS info.

 

[AKlowriderZ71]

On my truck, the rear bearing was trashed in the transfer case. That took out my ext housing bushing. That allowed my output shaft to wallow around, which is why the tone ring made contact with the sensor.

If you just replace the sensor without repairing the transfer case, you will still have the same problem.

 

[mike diesel]

I actually pulled the sensor out and the tone wheel has not made contact with the sensor. I pushed the drive shaft up and down with a dial indicator on the tone wheel and only had a few thousandths of movement, also took a video through the speed sensor hole watching the tone wheel as I rotated the shaft, it is in perfect condition.

The magnet on the sensor had zero shavings or filings on it also. I ohmed the sensor off the truck and got 1426 ohms. If I spun my drill past the magnet I could get the sensor to read up to 6000+ ohms...I have no idea what is normal though. Everything from TCM to speed sensor plug is fine, everything in the t-case case looks fine as well. Only thing left is the sensor itself...I'm assuming if there was a miscommunication between the TCM and PCM I would have other issues like like erradic speedo and slop shifting/abs light and other ABS codes, which I had none of those.

 

[mike diesel]

Found a buddy with a scanner that is ABS capable. He's fairly sure it can see live data from speed sensors and stuff. I'm picking it up this afternoon.

 

[JoshH]

See if you can look at freeze frame data from when the code was set. That might help you pinpoint what is going on.

edit: after reading the diagnostics for this code and your description of how the truck is acting, I believe you have a problem between the ECM and the EBCM or a bad connection at one end or the other. Check continuity from the C1 (blue) connector pin 46 to the big connector on the ABS module pin B3.

 

[mike diesel]

See if you can look at freeze frame data from when the code was set. That might help you pinpoint what is going on.

I will for sure.

Would the speed sensor reading have anything in anyway possible to do with engine fueling?For example...if the sensor is reading a tiny bit off (enough to set the code but not the lights on the dash...if that's even possible..) can it affect how the ECM commands fuel? I'm not sure how accurate this is but I read in another forum that the vss, maf and something else all work together to command the proper fueling of whatever the tune is calling for..is there any truth to this? I'm not a tuner so I have no idea.

Only reason I'm looking into this ABS code is to see if it is at all related to my 1st-mid 2nd gear lag that I mentioned earlier.

 

[mike diesel]

See if you can look at freeze frame data from when the code was set. That might help you pinpoint what is going on.

edit: after reading the diagnostics for this code and your description of how the truck is acting, I believe you have a problem between the ECM and the EBCM or a bad connection at one end or the other. Check continuity from the C1 (blue) connector pin 46 to the big connector on the ABS module pin B3.

I will do that right now.

 

[mike diesel]

I've got 0 ohms between B3 on the EBCM plug to pin 43 on the blue ECM plug. The circuit is open between either end of the plug and gound.

 

[JoshH]

Pin 46. There should be a yellow wire with a black tracer on both.

 

[mike diesel]

Sorry, that was a typo. I did test to 46, not 43.

 

[JoshH]

You confused me with the talk about ohms to ground. Did you check the resistance from C1 pin 46 to EBCM pin B3? Can you verify that both connectors have a yellow wire with a black tracer on the pins I indicated?

 

[mike diesel]

You confused me with the talk about ohms to ground. Did you check the resistance from C1 pin 46 to EBCM pin B3?

Yes i did.

I've got continuity between pin 46 and B3 and no continuity from pin 43 to ground or B3 to ground... which would be the same thing. So that circuit is good.

 

[mike diesel]

Yes both wires are yellow with black tracers.

 

[JoshH]

Here's the diagnostic chart for that code. Maybe it will help you get it figured out.

 

[mike diesel]

So before I started messing with it today I scanned it to make sure the code was still there and it was.

After unhooking everything during trouble shooting and reconnecting everything, also topped off the tcase fluid since the rear seal is leaking, I cleared the code and went for a drive. I cannot get the C0055 code to set anymore.

Took it on the highway, around town and neighborhood with no code afterwards. Also did four 60-0 mph full brake stops on dry pavement and ABS works great. Scanned it again and no codes. I will keep an eye on it for a few days to see if the code returns.

Can't say exactly what I did as to why the code won't set anymore because I have no clue what I did other than check continuity on those circuits and disconnect and reconnect tcm, ecm, and ebcm connectors.

 

[mike diesel]

Scanned it again with my autocal and the code was back.

I got ahold of that scanner, it is fairly nice, made by OTC and very similar to a tech 2. Scanning the abs system shows there are no codes present or in the history. Also watching live data from the speed sensors, they all are reading exactly the same and work perfectly.

I think im going to lay this to rest as either the autocal isn't reading codes right or that if the codes are right, it is a ghost code for whatever reason. I will throw the new VSS in and call it a day.

 

[05LLYDMAX]

I have had the C0055 code for exactly 11 months, and speedometer only works every once in a blue moon, brakes felt fine and I have the monitor for my speed so I wasn't in any hurry what so ever to get the sensor changed, BUT after a 4 wheel launch last week I started getting that funky 1-2 shift and 2-1 then all shifts randomly. Changing the sensor tomorrow so ill post on here for anyone with this issue in the future.