Fault U0121 stored in Gateway (TIPIM) module for 2011 jeep grand cherokee 3.6L

Hello everyone!

Reaching out in regards to CAN C BUS on a 2011 Jeep Grand Cherokee. I am new to a lab scope and CAN Network. ScannerDanner's CAN Network videos are what I am gaining exposure too. The shop I work at has been dealing with this vehicle for almost 2 weeks on an ABS concern. The ABS will not initialize properly to the vehicle and the ABS light will continue to flash on the cluster. ABS is unable to clear faults to adapt properly. The only fault stored in ABS is a VIN Mismatch/improper configuration. The technician has installed a new $300 ABS module and it did not fix it. Then a $900 TIPIM module (gateway) and concern is still present. SO, I took the opportunity and asked my boss if I could take a crack at it!! I am in need of some help with the CAN C network. I verified the powers and grounds for both ABS and Gateway. I am getting some weird looking CAN C signals. I also tried a cap discharge. The CAN C I am testing is communication from TIPIM and ABS. T- Resistance tested 60 ohms. Also, the PCM, TCM, SCCM, CCM, are on the same bus. Maybe try unplugging a module and monitor CAN C on scope for a change ? I uploaded some screen shots. Take a look guys! look forward to the responses!!! thanks you so much

To be clear, you've got an active U0121 in the TIPM, but you can communicate with the ABS module and get codes/data, correct? If so, I wouldn't sweat the network any more. IMO, those CAN signals may look a bit weird at some points? But you're also on a 100us timebase. Everything will look weird at 100us. :lol:

What are you using to initialize the new ABS module? The Modis Edge? If so, that may be part of the problem. I've had to initialize new and used ABS modules with my Modis before, and it's either an uphill struggle or didn't work at all. :silly: I bet that if you fix the VIN mismatch code, you'll fix the U0121.

Also, did the part numbers between the old and new ABS modules match? It sounds like a Captain Obvious thing, but the wrong module WILL bolt up and work, but never work properly. Ask me how I know!

Tyler wrote: To be clear, you've got an active U0121 in the TIPM, but you can communicate with the ABS module and get codes/data, correct? If so, I wouldn't sweat the network any more. IMO, those CAN signals may look a bit weird at some points? But you're also on a 100us timebase. Everything will look weird at 100us. :lol:

What are you using to initialize the new ABS module? The Modis Edge? If so, that may be part of the problem. I've had to initialize new and used ABS modules with my Modis before, and it's either an uphill struggle or didn't work at all. :silly: I bet that if you fix the VIN mismatch code, you'll fix the U0121.

Also, did the part numbers between the old and new ABS modules match? It sounds like a Captain Obvious thing, but the wrong module WILL bolt up and work, but never work properly. Ask me how I know!

Yes, I can communicate with ABS . I used my Modis to initialize the module as well as the Witech Chrysler scan tool. With the Chryster scan tool, I opened up the vehicle configuration data report and it stated that the ABS VIN was Invalid. And hahaha! yea I am learning the scope too. Its fun! Also, The part numbers were different. However, The new abs module this vehicle calls for has the correct part # per VIN. Not sure if it was a superseded part.

Where are you tapping into the network for your CAN waveform?

Without doing one recently, i cant remember but did you ever actually have to enter the VIN or is that taken care of via a flash? I remember the early to mid 2000's having to actually program the vin; to at least the pcm. What I'm getting at is how does the abs module learn the vin, and why wont it learn for you?

bruce.oliver wrote: Where are you tapping into the network for your CAN waveform?

I am backprobing at the back of the TIPM connector. I also tested same CAN lines at the back of the ABS connector and had the same waveform reading.

Sterline80 wrote: Without doing one recently, i cant remember but did you ever actually have to enter the VIN or is that taken care of via a flash? I remember the early to mid 2000's having to actually program the vin; to at least the pcm. What I'm getting at is how does the abs module learn the vin, and why wont it learn for you?

I like that question, if I go to ABS module under misc. Functions there is a configuration/ initilization tab. I didnt have to type in a vin on this modle. I know it wont initilize because the abs is unable to clear faults in the system. Oh! And I found out that the new abs module was not the correct part. The box had the wrong part in it. Getting the right one tomorrow. So ill update and let everyone know

damiconejon wrote: Oh! And I found out that the new abs module was not the correct part. The box had the wrong part in it. Getting the right one tomorrow. So ill update and let everyone know

Bingo! :lol: I dunno how they get this wrong so often, but it's happened to me and others.

I'm not very familiar with the WiTech, but I'm pretty sure there's a way to program the VIN into the ABS modules. Or, there's a way to get the modules to do a 'handshake'. Maybe spend some more time on the WiTech, see what kind of functions you have available? Look in the TIPM as well as the ABS module.

@ "Tyler"

Deffenitly man! I am excited to see what happens. I can save some logs on witech and email them to myself. Maybe I will find some cool evidence to post on here

Hello, frustrated because we got the wrong part again today. Something on Chrysler's end. The wrong part is being put into the box lol.

Hello,

I reached out to quality control for Chrysler and explained to them the situation regarding part # on ABS not matching what vehicle calls for. Long story short. Chrysler says that the part # is correct for the vehicle. The part # on new module is for the factory and not for the dealers use. So I am going to look at this again tomorrow.

I found a loose main ground by the brake booster! hahaha I cleaned it and tightened it back up, put the original ABS module and TIPIM back in. Car works sweet now.