C0055

Intermittent under semi hard acceleration. :(

DTC C0055
Rear Wheel Speed Sensor Circuit

DTC C0055
Rear Wheel Speed Sensor Circuit
Any idea on causes or diagnostics?

Can you go too fast and wear it out? ):h

Loose connection. Probably at the ABS controller.

Loose connection. Probably at the ABS controller.
I checked the connection at the sensor but completely failed at checking the controller. Thanks for helping me remove my head from my :D.

I have seen the speed sensor in the t-case overtightened, causing the reluctor wheel to make contact with the sensor on accel...

I grabbed a snapshot of it this morning on the way to work. It appears that the rear speed sensor is reading higher than the front sensors under hard acceleration by approx. 2-4 mph. Yet the tires are still glued to the pavement. Under cruise they all read the same.

Bad sensor?

Are you sure its not just not slipping the rear tires a bit? Maybe exaggerated by smaller worn rear tires?

Have you ever reprogrammed your tire size in the EBCM? Your EBCM is what holds the calibration for the front speeds, and the PCM does the rear. If the two do not match closer than 10 percent, you have a code...

The front 2 and rear match very well always within 1 mph under normal acceleration and even under cruise. Given that they match under cruise, wouldn't that preclude the calibration being off?
Additionally the code is intermittent, in other words not every accel will cause the code.

It does occur with the stock 245 tires and with the 285's. I even tried rotating the 285s front to rear. :confused:

It's seems like the sensor is picking up additional pulses under acceleration. I wonder if the yoke bushing in the transfer case is worn and allowing the output shaft to whip up and contact the sensor, duplicating what you had seen with an overtighten scenario?

I would remove the sensor and see if there is evidence of contact. I would bet that is it...Maybe try backing the sensor out 1/2 turn and see if it repeats?

Still sounds like a loose connection to me, but could be a shorting wire. Each open close of the circuit will be seen as a sensor pulse. Keep in mind that the signal is coming from the PCM and not directly from the sensor. The PCM modifies the signal based on gear ratio and such so that it should match the front and outputs it to the ABS controller. If the Speed signal being provided by the TCM to the PCM is bad, the PCM would complain. If the sensor was bad, the TCM would complain. So it goes Sensor -> Tcm -> PCM -> ABS controller.

Mechanical contact wheel / sensor seems to be a good explanation for me too. Had the "same problem" on a home position sensor in a Gantry of a CT Scanner (velocity errors intermittend). Sensor was damaged (touched). Exchanged the sensor and problem solved.
I know that seems VERY FAR from the problem described but the principle remains the same!

Driving around at lunch today, I noticed the speedo is now erratic, jumps around by 5-10mph intermittently. :(

I'll put on my detective hat tonight.:D

how about if you raise all wheels off the ground and moniter the speed at low speed on the scaner. I assume you have had the trans out and could you have pulled a tad to hard on the wiring harness. Check the pins and maybe add a small amount of dieelectric grease to the contact. is there any debri at the EBCM.

I bet a 12 pack if you loosen the VSS a 1/2 turn it goes away...

Driving around at lunch today, I noticed the speedo is now erratic, jumps around by 5-10mph intermittently. :(

I'll put on my detective hat tonight.:D
We will know soon, it is about to go from intermittent to full failure real soon. ):h

We will know soon, it is about to go from intermittent to full failure real soon. ):h
I like your thought process! :D

Probably because I agree with it. ):h