3.73 Gear Swap - Now Have Code "co245"

[GMC_BOI]

Hello. I had a 3.73 gear swap done on my 05 2WD Sierra 5.3. Now after 30 seconds of driving, I get the TC light, ABS light, and Service Brake System message. I get code CO245. My mechanic says he flashed the PCM to accept the new gear, but my speedometer is still off by about 13 mph, and I still get code CO245 with the warning lights.

 

If I turn off the car, the code and light disappears. It only happens again if I drive it for about 30 seconds.

 

Could this be a wheel speed sensor?

 

Thanks!

[gmtech4]

what is the code called ?????

 

your mechanic is not with GM is he ?,if not he cannot reprogram the BCM unless he has a GM account and $3500 in scanner equipment and lots of courses

 

clarify "mechanic"

[thearborbarber]

Your thinking is correct the pcm isn't set correctly for you new rear end. I caused the same problem when I was adjusting my tire size in the pcm for the trucks larger tires and punched in the size wrong.

 

If you get the two circles too out of kilter you will get the same errors you are asking about.

 

[minibike132]

C0245 is an internal solenoid test in the EBCM. There is pretty much nothing external to the EBCM that can cause the code. I think it is a coincidence that it set after the gear change. I can't say that for a fact but being an internal soleniod test it points directly to needing EBCM replacement, no amout of reprogramming will fix this.

[minibike132]

The speedo issue is because of the gear change and reprogramming is needed for that part of the problem.

[Z'06]

Time for either a custom PCM tune or at the very least a Superchips 2816 Tirepaq.

[GMC_BOI]

what is the code called ?????

 

your mechanic is not with GM is he ?,if not he cannot reprogram the BCM unless he has a GM account and $3500 in scanner equipment and lots of courses

 

clarify "mechanic"

 

 

The place I went to was a custom hotrod shop. Kinda small, but he has hotrods there all the time so I thought he would be reputable....

 

So I either need a custom tune, or have a dealer do this reflash for me? I called one dealer in Michigan, and he was totally clueless about what a reflash was....

 

Ok, so will a diablo hand held tuner work? Is anyone sure whether a predator would work for me?

 

There is a local guy near me that offers custom tunes. What speciffic program would he need to successfully reflash my truck? If you gentlemen tell me, then I can ask him what program he uses before I pay him...

 

Thanks for the replies! Please help me guys...

[thearborbarber]

A diablo will work for you as far as changing the gear ratio in the pcm goes.

[GMC_BOI]

A diablo will work for you as far as changing the gear ratio in the pcm goes.

 

Shouldnt the diablo fix my speedometer once the new ratio is flashed in?

[thearborbarber]

You are correct.

[GMC_BOI]

THE DIABLO FIXED EVERYTHING!!!!!!

 

And all I can say is CRAP THIS TRUCK FLIES NOW!!!!! The 93 tune I installed along with customing tuning it myself made the truck fast as hell!! Im gonna go through a set of tires fast! Lolol. I love it now!

[thearborbarber]

Like I said I triggered the same lights and codes adjusting for tire size. Scared the crap out of me because I was 20 miles from home and my laptop battery was giving out. Fortunately I made it to walmart and got a power inverter and got my laptop charging and found I forgot to punch in a digit.

 

For the folks that have been following this; it appears the pcm/bcm or abs computer compare the signal from the vss to the wheel sensors and if it detects a significant difference between the 2 you will get the following indications list by OP. This can be seen by a significant tire size change or rear diff ratio change.