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C0045-5A code issues - Wheel Speed Sensor

chuck804

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First time poster here. I'm in need of some help in addressing a C0045-5A code (Left Rear Wheel Speed Sensor Circuit - Not Plausible) on my 2008 Avalanche LS that will not go away. Below is what I have done with no success. No other codes are triggered. The ABS and traction control lights on the dash are illuminated, along with the messages on the display that the traction control and stabilitrac are off.

1. Replaced the speed sensor twice, cleaning up the grime around the hole and erased the C0045 code. Result: C0045 code pops up once the vehicle goes into drive.

2. Replaced the speed sensor connector: Result: C0045 pops up again after erasing code.

3. Removed EBCM to check for damage and temporarily replaced with a working EBCM with no ABS codes from another 2008 Avalanche to test. Result: C0045 pops up again after erasing code.

I traced the wiring from the speed sensor connector to the EBCM and did not see any noticeable breaks. Would it make sense to bypass the current wiring with new wire, tapping into the sensor wires at the EBCM? Thoughts?

Thx!
Charlie
 

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No the manual did not say. I would just try moving the axle by hand and see how much up and down play it has. See if it's leaking that's a dead giveaway the bearing is bad. I'll check again tomorrow for more info.
 

Capt.Crunch

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No the manual did not say. I would just try moving the axle by hand and see how much up and down play it has. See if it's leaking that's a dead giveaway the bearing is bad. I'll check again tomorrow for more info.
Great, I'll look in my manuals tomorrow and see if I can get a little more information about it, I'll let you know what I can find about that particular code.
 

Capt.Crunch

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Great, I'll look in my manuals tomorrow and see if I can get a little more information about it, I'll let you know what I can find about that particular code.
Oh, ok, I thought you were just assuming that the axle was moving up and down. But yeah, that would be the problem. Lol
 

chuck804

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I appreciate everyone’s input. So I took my truck to a local shop for a diagnostic to hopefully clear things up. Not only did the C-0045 code pop up, but now a C-0899 code as well for a EBCM/Device 1 Low Voltage. No other codes are present. Any thoughts on an approach ?
 

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It's hard for us to help you we are not there, what did the shop recommend.

Was the AV running when they checked the codes.
 

Capt.Crunch

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I was watching some YouTube videos on Avalanche electrical problems and I came across one that was talking about the ECM code, it was a bad ground on one of the pins, he cleaned the pin and it fixed all of his problems. I would pull the ECM plugs and see if they have corrosion on any of the pins.
 

chuck804

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Update here.

Taking Capt.Crunch's lead, I went to Youtube and found several videos regarding grounding and shorts. I pulled the EBCM connector to inspect and while all the pins were intact, some had a bit of corrosion. Not much but enough to potentially affect connectivity. So I sprayed some CRC electronic cleaner on the pins and harness, plugged it up, checked and cleaned two ground points near the EBCM, and cranked her up. Wow!!!! All ABS lights gone! Rescanned and no trouble codes detected. Many hours spent trying to figure this out and it took a simple cleaning to get it up and running again. So grateful for everyone's help and to Capt. Crunch for the Easter egg. This saved me a very costly trip to the dealership, no doubt.

A bit of a side note. While I did not notice any engine sluggishness during the ABS ordeal, once all the codes and lights went off, I noticed a huge improvement in throttle and engine responsiveness. I'm sure something within the vehicle was compensating to keep it running.
 

Capt.Crunch

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Update here.

Taking Capt.Crunch's lead, I went to Youtube and found several videos regarding grounding and shorts. I pulled the EBCM connector to inspect and while all the pins were intact, some had a bit of corrosion. Not much but enough to potentially affect connectivity. So I sprayed some CRC electronic cleaner on the pins and harness, plugged it up, checked and cleaned two ground points near the EBCM, and cranked her up. Wow!!!! All ABS lights gone! Rescanned and no trouble codes detected. Many hours spent trying to figure this out and it took a simple cleaning to get it up and running again. So grateful for everyone's help and to Capt. Crunch for the Easter egg. This saved me a very costly trip to the dealership, no doubt.

A bit of a side note. While I did not notice any engine sluggishness during the ABS ordeal, once all the codes and lights went off, I noticed a huge improvement in throttle and engine responsiveness. I'm sure something within the vehicle was compensating to keep it running.
That's AWESOME!!!! I'm glad you were able to find the problem, the grounding system on the Avalanches are TERRIBLE! Most of the charging system problems are because of the corrosion, my 2010 would always show it discharging and had a lack of power/fuel management problems, I didn't have any check engine light or codes in the computer. I cleaned the terminals on the computer and it ran like a new truck again and it also shows a constant 14.6 volts on the charging system. A lot of people are saying to do the big 3 wiring bypass on them and it still doesn't fix the problem. I also learned by experience that just cleaning the computer terminals will fix a lot of the electrical problems and running issues. Glad I could be of help.
 

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I am glad you got this sorted out.

Electrical issues can be the worst.

Way to go, Capt.Crunch!

:) (y)
 

SpottyJ

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A thread like this shows why this forum is so awesome. Thanks Capt. Crunch!
 

HVACMAN

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So good info., but my code (C0045) and dash lights (abs.trac cntrl) only showed up after replacing my rear air shocks (LTZ) with correct replacement Delco shocks.
Why would that cause any of those things talked about above?
 

Capt.Crunch

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So good info., but my code (C0045) and dash lights (abs.trac cntrl) only showed up after replacing my rear air shocks (LTZ) with correct replacement Delco shocks.
Why would that cause any of those things talked about above?
There are 3 grounding wires on the rear of the frame rail, by the driver side bumper, I would check them for rust, you may have moved them while installing the shocks, also check for plugs in that area and make sure they are clean and tight.
 
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