ABS error from tire size change.

I have done a search on this, but got some reason, this file does not have the parameter that was listed as a fix.
There are a few threads talking about this from 2010, but I didn't see any fix for this. Just people talking about it.

I've got someone who has swapped to 37" tires on their 2008 Silverado.
I don't have a VSS output to modify like the 2007 trucks.
I've tried a few different tunes. Don't know what to change for the speedo, yet won't trip an ABS light.

I've changed the VSS Tire Revs per, and that tripped the light.
I modifed the Dist-Err values, tripped the light. I returned the final drive ratio err to stock. Tripped the light.
I also tried falsifying the rear gear ratio, and that got the light too. This is the tune I have posted here.

Help please.

did you try changing the vss tire revs info by the percentage difference of the two tire heights?

Yep, tried that.

I've been looking around, and some claim that you can't go over 35" otherwise the light will trip. I've also heard that you need a tech2 to change the BCM and such.

I'd like to know what to do. I licensed this vehicle just to alter tire size, and I may need to go a different route.

Anyone have any ideas?
Am I just unable to make such a big change?

Generally the ABS module has its on set of pre programmed tire sizes in it and just programming the ECM will not change the ABS module. Only a tech two will do it.

I just tried recalibrating my 08 Sierra and had the same problem. I have 34.7 inch tires. I drove about a mile before the ABS light came on. I am using the 2.23 beta software and it does not have the ppm adjutment that I could find. That was a suggested fix in one thread. I am considering maybe just putting in a 34 inch tire to get the speedo close and hopefully be within the acceptable difference between front and rear tire sensors. Another suggestion was to adjust the general VSS ppr but then you would need to manually adjust the trans shift points. Would I be able to just adjust the trans shift points by the tire size percentage difference? Say its 10% difference just adjust the shift MPH by 10%?

I'm having the SAME issue guys. I'm using Beta 2.23.279, and I have access to this additional table:

http://lh6.googleusercontent.com/-KI...Q/s800/vss.JPG

I'm working on a 2003 Silverado 2500 with 35" tires. Problem is, after I corrected the speedo via the auto scale and then tweaking the General output pulses/mile to get the speedo dead on, the ABS and Brake messages come up at times.

The OLD way to do it...used to be that you had to have the ABS module tire size changed to the maximum to keep it within tolerance from setting the codes for wheel speed mismatch front to rear.

However, if i'm reading this right, with this Beta version, I can change the pulses/mile to the ABS module, thereby fixing the issue?

Looking at the wiring schematics, the ABS gets a dedicated speed signal from the PCM on C2 Pin 49, whereas the Cluster and other modules get the VSS from C2 Pin 50. So, modifying the ABS Pulses/mile box should only affect the output on the ABS circuit.

Anyone else tried this yet? I think i'm going to tonight and see how it pans out. :shrug:

Worked out great. Changed the VSS Pulses/mile for the ABS only. Had to modify it inversely from the General VSS that I changed, but that makes sense as you want to keep the PCM's VSS output to the ABS identical as it was before.

Quote:

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Originally Posted by 96gt4.6

Worked out great. Changed the VSS Pulses/mile for the ABS only. Had to modify it inversely from the General VSS that I changed, but that makes sense as you want to keep the PCM's VSS output to the ABS identical as it was before.

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so, can you be specific on the exact change you made on the general vss pulse and the abs pulse, i.e. xxxxxx to yyyyyy. also, do you have 4 channel abs?

^ Replied to your PM sir. And, the answer to your question is in the 1st post as well, just change the ABS Pulses/Mile exactly inverse of the VSS pulses/mile change.

Truck has many miles since this with no ABS/Brake lights!

I got 99 t/a with mix match rims 17 in front and 18 in rear. Is this way to fix the abs light or do i have to reprogram my abs module?

tried modifying the abs pulses the inverse percentage i adjusted my speedo. no luck. speedo is right on but abs will still throw the lights. maybe this field doesn't affect anything for the 01 camaro pcm i use.

anybody else get it to work this way?

^ Are you running a Camaro ECU in a pickup, or are you trying to use this technique on a Camaro/Fbody?

its in a camaro. went from 3.42 rearend to 3.50. increase speed pulses up by 2.339% and the abs pulses down by 2.339% . speedo is now right on, abs still throws codes c0245 and c0051. i have replace the rear sensors also just in case!

That would probably be why you are having such an issue.

The Truck PCM's output a speed signal from the tailshaft Speed Sensor to the ABS module, this output is able to be changed in the tuning by the method we have been discussing.

The Camaro's, however, have 4 independent wheel speed sensors, and do not rely on the trans tail sensor for an input, so changing the ABS VSS Pulses/Mile would have no effect.

From my perspective, on an Fbody, you have 2 choices:

1. Have the tire size changed to the maximum size or closest to the rev/mile of your setup via a Tech2 at the dealership.

2. Deal with the light.

But, i've never had to experiment with the Camaro's yet. I've only had to apply this to the pickup's.

thx. taking the camaro in to the gm dealer on monday. i'll let everybody know what they say.

Any luck sir?

my gm dealer was worthless. charged me 100 to tell me i had a problem but had no solution.

as mentioned earlier, speedo is right on. changing the abs pulses was not needed (nor did i know if it even makes a difference on a camaro. hptuners never answered my question about it!) anyhow, it appears my problem was due to the rear toner rings being installed poorly by the place who built my 9 inch rearend. that were too close to the lug studs as well as not being rotationally true, ie. they had a slight wobble. i ended up buying software from palmer performance that could monitor all 4 abs wheel speed sensors while i drove the car. i was able to confirm the inconsistencies in the reported sensor speeds which led me back to discovering the toner ring issue.

Quote:

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Originally Posted by mterveen

i ended up buying software from palmer performance that could monitor all 4 abs wheel speed sensors while i drove the car. i was able to confirm the inconsistencies in the reported sensor speeds which led me back to discovering the toner ring issue.

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Another great idea for feature additions to HPT software.

Quote:

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Originally Posted by mterveen

i ended up buying software from palmer performance that could monitor all 4 abs wheel speed sensors while i drove the car.

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Were you able to use the HP Tuners ODBII cable or did you have to use a different one?