Jump to content

How to correct ABS after gear swap classic model


Recommended Posts

New here. I recently swapped my 3.23 ring and pinion to 3.73 ratio and went through much grief with ABS warnings and harsh shifting before I finally found a fix. I thought it was worth sharing because after much research I have not come across a solution shared by someone else with the same experience. I have an 07 Classic model 1500 5.3l flex with 4L60E 2WD (Z82/Z85). I thought I could simply install the gears, purchase a Hypertech programmer, and change the settings in the computer. While this corrected the speedometer and shift points, this did not satisfy the ABS module. Apparently the computer does not send the re-calibrated information to the ABS module, so it thought the rear wheels were spinning faster than the front even after reprogramming the computer. So, I reset the computer to factory, purchased an Electronic Ratio Adapter (ERA) from Abbott Enterprises and installed this in-line from the VSS. This seemed to have corrected everything until the first long trip I took. Suddenly, the transmission began slamming every gear. It turns out that some genius decided one year to add an input shaft speed sensor to the 4L60E. Dialing down (re-calibrating) the VSS with the ERA gave the computer the impression that the output shaft was spinning slower than the input shaft (when at 1:1) which triggered a component slippage code. The default in the computer for this situation is to apply FULL pressure on all shifts thereby making an attempt to break metal components vs. burning easily replaceable clutches (which REALLY sucks when you consider a few of the weaker components common to the 4L60E). Fortunately, I was able to remove the ERA from the VSS before destroying the tranny.

 

Now the fix:

The ERA is capable of being set for A/C or D/C signal re-calibration using four pins set on or off (Abbott Enterprises was extremely helpful by email and always responded timely). I set it for D/C signal and placed the ERA in-line in the signal wire from the computer VSS out to the ABS module and calibrated for the change to 3.73. Then, I tuned the computer with the Hypertech setting it for 3.73 ratio. Finally - all shift points are correct, the speedometer is correct, no more ABS lights, and the ABS warning no longer chimes 33 times EVERY SINGLE TIME the truck is re-started.

 

At one time it was possible to pay your stealership to reflash the computer and ABS modules, but the ones around here all refused claiming that they cannot make any alterations to the vehicle beyond the way it came from the assembly line, even though 3.73 gearing was a factory option. However, with the Hypertech and ERA I have the option to install other ratio gears and re-calibrate in the future. Please share - I am hoping to save others valuable time and money performing what used to be a simple task.

Link to comment
Share on other sites

I put 4.11 gears in place of the factory 3.73 gears in my 07 avy. I used hp tuners to calibrate revs per mile, vss rpm, input rpm, error factor, and move the shift points up a bit. No issues with abs or stability. I think maybe those handheld devices skip a calibration or so. My advise is either buy hp tuners, or have someone tune it for you.

Link to comment
Share on other sites

I actually debated going with 4.11s myself, but thought it would be easier to go with 3.73s because it was a factory option for that model. Had I known better going into this I would have installed 4.11s. I found it hard to believe that with all the research I did going into this that I was unable to find someone with a solid solution. It seams as though everyone has different issues depending on model year and whether or not they are 4x4. Some people say they only change tire size and have difficulty. If the reluctor ring were left in the rear end it would not have been an issue at all.

 

How do you like those 4.11s?

Link to comment
Share on other sites

I really like them. I bought Yukon Gear, and they have a little whine to them at 40 and 60. To counteract that, I just drive 30, 50, and 70. I did a detroit trutrac in the rear which really pulled the package all together. When I floor it, it hauls ass. Not bad on Highway rpms at 85 either, mileage? Who cares...

Link to comment
Share on other sites

I went with Motive Gear. My factory 3.23s whined between 40 and 60 and so do the Motive 3.73s, just not as loud. Kept the stock G80 locker. What did you mean about paying $100 to unlock the HP tuner? I refrained from purchasing this due to the $650 cost with an understanding that every time I wanted to make a change it would subtract a credit. I would have burned through all of mine already.

Link to comment
Share on other sites

No StabiliTrak on mine. It has the so-called 4 wheel ABS, but really more like 3. Each front wheel has a speed sensor and the rear wheel speed is monitored by tranny tailshaft speed, the VSS. Changing the rear gear ratio setting with a Hypertech would have worked just fine IF the computer changed the signal to the ABS module. The ERA would have worked in place of Hypertech IF there was no tranny input shaft (turbine) speed sensor that was used to monitor for component slippage. If mine had a reluctor ring at the ring gear it would work just like having individual sensors at each wheel.

 

I saw the hptuner comes with 8 credits. Are you saying it is one credit per vehicle and not one credit per tune? Can it be used to alter (calibrate) the VSS OUT signal from the computer to the ABS module?

Link to comment
Share on other sites

  • 5 years later...
On 2/24/2017 at 8:27 PM, Chevy383 said:

New here. I recently swapped my 3.23 ring and pinion to 3.73 ratio and went through much grief with ABS warnings and harsh shifting before I finally found a fix. I thought it was worth sharing because after much research I have not come across a solution shared by someone else with the same experience. I have an 07 Classic model 1500 5.3l flex with 4L60E 2WD (Z82/Z85). I thought I could simply install the gears, purchase a Hypertech programmer, and change the settings in the computer. While this corrected the speedometer and shift points, this did not satisfy the ABS module. Apparently the computer does not send the re-calibrated information to the ABS module, so it thought the rear wheels were spinning faster than the front even after reprogramming the computer. So, I reset the computer to factory, purchased an Electronic Ratio Adapter (ERA) from Abbott Enterprises and installed this in-line from the VSS. This seemed to have corrected everything until the first long trip I took. Suddenly, the transmission began slamming every gear. It turns out that some genius decided one year to add an input shaft speed sensor to the 4L60E. Dialing down (re-calibrating) the VSS with the ERA gave the computer the impression that the output shaft was spinning slower than the input shaft (when at 1:1) which triggered a component slippage code. The default in the computer for this situation is to apply FULL pressure on all shifts thereby making an attempt to break metal components vs. burning easily replaceable clutches (which REALLY sucks when you consider a few of the weaker components common to the 4L60E). Fortunately, I was able to remove the ERA from the VSS before destroying the tranny.

 

Now the fix:

The ERA is capable of being set for A/C or D/C signal re-calibration using four pins set on or off (Abbott Enterprises was extremely helpful by email and always responded timely). I set it for D/C signal and placed the ERA in-line in the signal wire from the computer VSS out to the ABS module and calibrated for the change to 3.73. Then, I tuned the computer with the Hypertech setting it for 3.73 ratio. Finally - all shift points are correct, the speedometer is correct, no more ABS lights, and the ABS warning no longer chimes 33 times EVERY SINGLE TIME the truck is re-started.

 

At one time it was possible to pay your stealership to reflash the computer and ABS modules, but the ones around here all refused claiming that they cannot make any alterations to the vehicle beyond the way it came from the assembly line, even though 3.73 gearing was a factory option. However, with the Hypertech and ERA I have the option to install other ratio gears and re-calibrate in the future. Please share - I am hoping to save others valuable time and money performing what used to be a simple task.

 

@Chevy383 Hope you are still out there as this thread is over 5 years old. I have a 2007 New Body Style 2WD JF3, so my truck has the two front wheel sensors and none on the rear wheels. I have been running aftermarket wheels and tires on for the last 26,000 miles. Switched from a 245/70/17 (30.5 in circ) to a 275/60/30 (32.99 in circ). I decided to change out the differential from a 3.73 to a 4.11 and got the truck back right before this weekend. Going over 65 MPH for a minute or two will throw code C0245 for Wheel Speed Frequency Sensor error with the Brake light and ABS lights. It looks like the Abbot ERA is still available and I plan to go that route and don't plan to do any speedo corrections as my 30.5 tires with 3.73s to a 32.99 with 4.11 is only a 1.8% difference on final drive. I now get though that yah, final drive is the same, but how I get there with the new 4.11s is throwing up the brake and abs lights.

 

My goal is to get my ABS (not speedo) tricked into thinking it still has 3.73s.

 

Question: What specifically did Abbot have you do on the 4 dips to switch it from AC to DC? I assume that change is because the 4L60E sends an AC sine signal while the ECM send a square wave to the EBCM?

 

Was your correction factor just 3.23/3.73 = 0.8659?

 

I was looking at the Dakota Digital SGI-100BT, and it specifically says in there to NOT use their module for ABS corrections as it can cause it to behave erratically. Not sure if this is just maybe a liability thing vice a compatibility thing.

 

Hope you're still out there and have some info :) 

ABS VSS Wiring.png

Edited by Will Heermann
Link to comment
Share on other sites

Success. I was able to use the Abbott ERA to suppress the C0245 error, and got rid of those ABS and Brake light illuminators. I just took 3.73/4.11 to get my correction factor of 9.075. I then had to choose to set the Abbott ERA to either 9.05 or 9.1, and I chose 9.1 I configured the Abbott ERA to DC square wave mode by setting the 4 pin configuration switch from the shipped default of 1000 to 0110 after a quick call to their support line.

 

Abbott also recommends putting the ERA as close to the sensor as possible, which in my case the “sensor” was the ECM under the hood. Using my service manual I referenced their “X1” to connector “J1” on the ECU. I opened up the harness and immediately saw a Yellow/Black wire. Instead of splicing into it I just shaved off a bit of insulation, hooked up my o-scope, and went for a drive. I never saw anything on the line, so came back to garage and dug into the harness a bit more and found another yellow/black line that was a much smaller gauge (18 – 20-ish), shaved off some insulation and went for a drive. Even backing out of the driveway my scope displayed a square wave and I knew that was the line. I took it out on a drive and wrote down the displayed frequency from 20 – 75 mph in 5 mph increments. 1.1 miles in at 65 MPH I received my ~33 chimes and ABS/Brake Fault Lights. I then cut the line (nerve-racking!!) and rough twisted/taped the ERA in place to go for a test drive, writing down the frequency again. I had made a “calculated” frequency column which was my originally recorded values x 0.91 so I knew that was in the ballpark. The signal was decently clean, and with the same driving profile no alarms or illuminators and the displayed frequency tracked very closed to my projected calculated values!

 

Now for the full installation.

 

I ran an 18 AWG shielded pair (not twisted shielded pair) from home depot that was sold as alarm wiring for $0.33/ft. I placed it in some of the plain corrugated conduit (1/4”) and ran it from the ECM, outboard of the brake-booster, down the back wheel-well, and penetrated the firewall about 1.5” inboard of where the parking brake cable transitions into the cab. I made a quick bracket out of some scrap and mounted the ERA right underneath/outboard of the steering column. The ERA unit is not sealed so it is clearly not meant to be placed in the elements. Of my 12’ of shielded cable that I purchased from the Depot I had a little under 5’ that I cut off, so a 7’ run in total. Since it is square wave is why I opted to go with a shielded cable to ensure noise wouldn’t be an issue. The alarm wire is stranded, foil jacketed, with a non-insulated drain wire that I pulled over to a ground location that I have from a previous fuse panel add-on install. I asked Abbott about fuse rating, and they recommended a 5A.

 

Another reason why I chose to cut the ECM side was looking at the EBCM harness IRL there were at least 3 Yellow/Black wires that I identified running into it and I didn’t even want to try to figure out which was which, so the ECM was a much more straight forward approach. My cut into the ECM was less than 1 foot away from the J1 connector.

 

I had 2 phone calls to Abbott along with a few emails, and I must say that their personal approach, tech support, and customer service is absolutely outstanding. I am going to follow up with them this week regarding my 75 MPH square wave as the square wave has a small amount of distortion, but with the obvious lack of an ABS/Brake light, the EBCM seems to manage it just fine.

 

This fix is specific to vehicles with the JF3, JF7, JH6, or JH7  RPO code that have a a sensor on each front wheel and the 3rd piece of data coming from the VSS.

 

JL4 vehicles have a sensor on all wheels that directly feed the EBCM so I can't speak to any issues there.

 

Abbott ERA Graphical Schematic Routing.png

Abbott ERA Graphical Schematic.png

Abbott ERA Install.png

EXCEL PNG.png

IMG_20221105_090116093_HDR.jpg

IMG_20221105_210029154_HDR.jpg

Edited by Will Heermann
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Forum Statistics

    245.8k
    Total Topics
    2.6m
    Total Posts
  • Member Statistics

    333,236
    Total Members
    8,960
    Most Online
    Lightning123
    Newest Member
    Lightning123
    Joined
  • Who's Online   3 Members, 0 Anonymous, 699 Guests (See full list)



×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.