Had 4.56s installed, now getting C0035 and C0245 codes

[Escapepilot]

Everything was fine till I had a shop install the gears and fix those damned broken exhaust bolts. Since the 5.3 is crowded in the TB, they pulled the engine to fix the exhaust bolts and gears. Now, I'm getting the C0035 and C0245. They don't come on right away. I've cleared the codes and it will be ok for a few miles - maybe even 4 or 5 - before the abs and brake lights come on. The left side (c0035) has had a sensor replaced less than a year ago and less than 2000 miles. I pulled the sensor and didn't notice anything unusual about it in general. I also noticed that on the right side, the wires going to the axle disconnect are no longer in a wire loom and it looks like they have been spliced I don't know if they were spliced before and don't know it there could be any connection.

OK, troubleshoot tips?? The sensor has a limited lifetime warranty to I'm considering replacing it if they'll honor that w/ a no cost replacement. Other things to check??

Thanks.

 

[Mooseman]

Those codes are for a problem either in the wiring or the sensors circuit open or shorted to ground. I'd suspect something with the wiring with that much work done.

 

[Paul Bell]

OK, I just gotta ask: Why 4.56 gears?

 

[coolasice]

Might be relevant... http://gmtnation.com/forums/topic/14024-abs-shutdown-due-to-410-axle-swap/

 

[HARDTRAILZ]

OK, I just gotta ask: Why 4.56 gears?

I wish I had 4.56. You really should do lower gears with bigger tires. My 4.10 gives me an effective 3.55 ratio and 4.56 would put me back to close to my stock 3.73.


I would not trust the splice and replace that wire asap.

 

[Escapepilot]

Had 3.73s but went w/ the 4.56s when I went to 35x12.50s.

Found the receipt for the wheel sensor I replaced last year and swapped that last night. So far, the c0035 code is gone. However, the c0245 flashed again last night during the test drive. I'll try to slide under there tonight and check the wiring for obvious damage.

Thanks for the tips.

 

[Pittdawg]

Had 3.73s but went w/ the 4.56s when I went to 35x12.50s.

Found the receipt for the wheel sensor I replaced last year and swapped that last night. So far, the c0035 code is gone. However, the c0245 flashed again last night during the test drive. I'll try to slide under there tonight and check the wiring for obvious damage.

Thanks for the tips.

Your profile says 4.8 liter V8?

 

[Mounce]

However he states in his first post that he has the 5.3. Probably just a typo/confusion when he was filling out his profile.

 

[coolasice]

C0245 will never go away due to the gear change.

 

[HARDTRAILZ]

C0245 will never go away due to the gear change.

I never got that code with my gear change...

With all the gear changes I have seen some speedo issues, but not codes.

EDIT-- There are a couple members working on the ABS issue, but most I have seen change gears did not get a code.

 

[coolasice]

See my link earlier up

 

[HARDTRAILZ]

I know that thread well. I forgot it actually had a code with the issue. I knew that the ABS got wonky on BT and Shadow but there are a dozen or so on ORTB that did not have same issue IRRC. I did not think it was a standard code everyone got.

 

[coolasice]

I think it depends on the change... He went from 3.73 to 4.56, that's a huge jump. If he went from 3.73 to 4.10 it may not throw a code as the difference is minimal.

 

[djthumper]

It seems that the 2004s have more issues with changes than any other year.

One of the guys went up to 4.10s and had problems with ABS codes coming up. You have to make the changes in the PCM. in the 2006 and newer it seems they can make more adjustments to the PCM.

 

[coolasice]

It seems that the 2004s have more issues with changes than any other year.

One of the guys went up to 4.10s and had problems with ABS codes coming up. You have to make the changes in the PCM. in the 2006 and newer it seems they can make more adjustments to the PCM.

Has to do with the 2002-2005 having 3 abs sensors vs the 4 on the newer models. Noone has found the settings for the pcm to change axle ratio in the older models, you can only flash the pcm to one of the original ratios, 3.42 3.73 4.10.

 

[Sparky]

Yep. Gear changes on the old ones can make things unhappy because that 3rd sensor is on the tailshaft and affected by the differential. 2006 and up have the sensors on the rear wheels directly so they are not affected by gear changes, even if you don't flash the PCM.

Now if the 3rd sensor was off the diff watching a reluctor wheel on the ring gear like on my Camaro then the ABS would never be an issue with a gear change. I'm not entirely sure why they put it on the tail shaft and dealt with having different programming for different gear sets vs just putting it off the diff.

 

[HARDTRAILZ]

Maybe we should merge this and the linked post since it is the same info being discussed

 

[djthumper]

Has to do with the 2002-2005 having 3 abs sensors vs the 4 on the newer models. Noone has found the settings for the pcm to change axle ratio in the older models, you can only flash the pcm to one of the original ratios, 3.42 3.73 4.10.

I know about all of the older ones. The 2004s seem to have more issues than the other years. even when only going up to 4.10 ratio. A few other guys with 2004s have had more issues than even 2002s.

Those of us on ORTB have seen this a few times.

 

[Escapepilot]

After reading the link coolasice posted, I have a few more thoughts on the subject.

I ran stock 3.73s for a few months before changing to 4.56s w/o any abs issues (w/ the 35s). If the issue is the expected tire speed based on the rear tailshaft sensor, wouldn't the 35s still cause it to be off? Or, would the computer see everything the same since it is looking for an expected rpm which didn't actually change...the TB just moves faster for any given rpm.

Changing to 4.56s w/ 35s put the engine rpm/speedo very close to the original 3.73 w/ 245/65r17s. The rpm difference is w/in 50 rpm in most instances and w/in 3 mph of actual.

I've noticed abs pumping as I am almost stopped w/ light braking.

Could the issue be caused by the new setup causing the computer to see the tires turning slower than before? Would somehow causing the tires to turn slightly faster than expected solve the issue?

 

[Escapepilot]

Your profile says 4.8 liter V8?

Fixed it. Probably accidentally clicked the 4.8 instead of the 5.3 and didn't notice.

 

[Escapepilot]

Using the gear ratio calculator on offroadtb, it says I should be turning 1828 rpm w/ 4.56s and 35s at 60 mph. With 3.73s and stock tires at 29.5 diameter, I should have been turning 1774 rpm. So...w/ the 4.56s, I'm turning a higher rpm which could be making the ebcm think a tire is sliding. Since both front tires are sliding the same amount, there must be a system error.

Since Chevy didn't offer 4.56s, I can't swap a pcm like in the other post, but...

What if I reprogram the pcm w/ 4.10 gear info? That would cause the pcm and bcm to think the tires are rotating faster than expected and not sliding. Would that work? Or, would that cause the same error for a different reason...not that the tires are rotating too slow, but not rotating at the proper speed??

Ideas? Comments?

 

[djthumper]

For some reason I think you need a tech2 to be able to activate and read the components to see what you really need.

 

[Sparky]

After reading the link coolasice posted, I have a few more thoughts on the subject.

I ran stock 3.73s for a few months before changing to 4.56s w/o any abs issues (w/ the 35s). If the issue is the expected tire speed based on the rear tailshaft sensor, wouldn't the 35s still cause it to be off? Or, would the computer see everything the same since it is looking for an expected rpm which didn't actually change...the TB just moves faster for any given rpm.

Changing to 4.56s w/ 35s put the engine rpm/speedo very close to the original 3.73 w/ 245/65r17s. The rpm difference is w/in 50 rpm in most instances and w/in 3 mph of actual.

I've noticed abs pumping as I am almost stopped w/ light braking.

Could the issue be caused by the new setup causing the computer to see the tires turning slower than before? Would somehow causing the tires to turn slightly faster than expected solve the issue?

ABS is looking for the same relative sensor reading at all sensors. The 3rd sensor being on the tailshaft is looking at the speed of the driveshaft, not the rear wheels, but the computer is programmed for that at whatever gear ratio your truck has, so everything is as expected. When you increase tire size it doesn't affect that ratio any, so the computer doesn't get angry.

Now, when you re-gear, the sensor now sees the driveshaft spinning at a different relative rate to the front wheels than it used to, and that's when it gets all angry. In your case, it is expecting 3.73 turns of the driveshaft for every 1 turn of the front wheels. Instead, it is seeing 4.56 turns of the driveshaft for every 1 turn of the front wheels and it is getting all flustered over it.

Reason why 2006 and newer does not have this problem is they have 4 channel ABS, which puts a sensor at each rear wheel instead. Now they are no longer affected by the gear ratio as they are looking at the wheels directly.

 

[Escapepilot]

ABS is looking for the same relative sensor reading at all sensors. The 3rd sensor being on the tailshaft is looking at the speed of the driveshaft, not the rear wheels, but the computer is programmed for that at whatever gear ratio your truck has, so everything is as expected. When you increase tire size it doesn't affect that ratio any, so the computer doesn't get angry.

Now, when you re-gear, the sensor now sees the driveshaft spinning at a different relative rate to the front wheels than it used to, and that's when it gets all angry. In your case, it is expecting 3.73 turns of the driveshaft for every 1 turn of the front wheels. Instead, it is seeing 4.56 turns of the driveshaft for every 1 turn of the front wheels and it is getting all flustered over it.

Reason why 2006 and newer does not have this problem is they have 4 channel ABS, which puts a sensor at each rear wheel instead. Now they are no longer affected by the gear ratio as they are looking at the wheels directly.

After thinking about it some more, I came to that realization. The tire size is irrelevant. Think of the two front sensors being on the rear hubs instead. Then, ONLY the correct gear ratio will work. Unless there is a way to reprogram the pcm for 4.56s or to fool it into thinking it still has 3.73s, there isn't a solution.

 

[Mooseman]

The Tech 2 can't reprogram for gear changes. It may be possible to possibly reprogram the PCM, BCM and ABS modules with the proper software version according to the stock gears available but I don't know how to figure which software version works for what options. And that's IF a particular gear ratio was available for a particular engine version. I don't think 4.10's were ever available with the 4.2L and 4.56's were never available as an option at all.

2002-2005 aren't programmable through HP Tuners but apparently 2006+ are. For the Tech 2, as far as I can tell, it can only reprogram for tire size on 2006+.

 

[djthumper]

4.10 came in several 2WD 4.2L

 

[Escapepilot]

With all things computerized, there has to be a solution...we just haven't found it yet. Since it can be changed to other factory offered ratios, it must be changeable. A custom program can change just about anything else so why not that? I've read that Diablo's intune can change ratios on some vehicles, but didn't see the TB so I just sent an email asking. If they can, I'll be sure to let you know.

 

[Paul Bell]

I've noticed abs pumping as I am almost stopped w/ light braking.

I have this also-and everything is stock. I've been advised by a few brake system know-it-all guys that the ABS reluctor ring in one of my front hubs is cracked. It happens at almost every stop in stop & go traffic. I have new hubs waiting to go in. This issue is noted in some trouble shooting guides.

So THIS issue you're having may be hub sensor related.

Sorry I can't help with everything else.

 

[Mooseman]

The ABS kicking in when almost stopped is usually due to a failing hub. The very odd time it's the sensor.

4.10 came in several 2WD 4.2L

Problem using the software for that would kill the 4x4 system because the BCM wouldn't be programmed for it.

 

[coolasice]

The ABS kicking in when almost stopped is usually due to a failing hub. The very odd time it's the sensor.



Problem using the software for that would kill the 4x4 system because the BCM wouldn't be programmed for it.

AND he has a 5.3....

 

[Mooseman]

I was on my phone when I answered this so missed that. Doesn't change anything though. Finding a proper software version would be impossible because of the 4.56 gears.

 

[Sparky]

It is worth nothing that since he has a 5.3 he can tune the computer for tire sizes and everything. That limitation was only for the 4.2L computers.

Thing is, I don't know where or how to fix the ABS codes since that isn't handled by the PCM. At least I don't think it is... Would be interesting if he tuned the PCM for the 4.56 gears and the ABS codes went away.

 

[Escapepilot]

I'm looking a few options. Superchips GM Flashpaq may work, but only for the 5.3 guys. I also have talked to a company about the ratio corrector which would fool the rear sensor into seeing the proper gearing but would then cause the speedometer to be off.

I'll keep updates posted here in case anyone else has the problem or a solution.

 

[Pittdawg]

Have you talked to PCM of NC? They're very well versed in our platform.

 

[Escapepilot]

Have you talked to PCM of NC? They're very well versed in our platform.

Yes. They can't fix that particular issue.