TAC32 1922/1920 faults

I have a TAC32 that had a power surge. I have replaced the CPUA, IOD and CWIL boards. I can not communicate with the CWIL board. I believe the no communication to the CWIL is causing my SP and NP faults. When I put in VER the Safety processor and NP processor both read V0R0. Everything else has a version. If I do an RFL with the 1922 and 1920 faults I will instantly get 1154,1124, 1152 and 1153 faults. I have meter my communication CCL-CCH and I have 4.6VDC. Any help is very appreciated

So first make sure 60 ohms from CCH to CCL with power off, that’s 120 ohms at the IOD (actually from CPUA jumpers) and 120 ohms at the CWIL (resistor soldering the board). A good CAN channel should read about 2.5vdc from high to ground and slightly less from low to ground and should be fluctuating. If it’s much off of that you want to unplug boards until you find which is causing the problem. Ideally, you would have started with just the new CPUA, IOD, & CWIL with nothing else attached to the CAN channel and see if you could get the MAINCOP to show up with a 1 when you type in a DCN command. Then add the door board, then selector. If one of those causes you to loose CAN then that board is bad. Also beware of the CE electronics board in the controller, if you have one, I’ve seen that pull down the whole C channel. And at a minimum after replacing those 3 boards you’ll have to load the job & generic in the CPUA, do a TECC to teach the CWIL, and do an SPC with the SP jumper on pins 1-2.

I have 88.9 ohms on CCL to CCH with connector off on IOD board. With wires on it is constantly changing. I checked it at the CWIL board with it disconnected from the CWIL board and it just bounces around. I believe when I checked the actual voltage on the line to ground the CCH had 4.5vdc and CCL had 0.

Well none of that sounds right. The resistance measurements are taken with power off. There’s no reason to even turn the power on until the loading resistance is right.

I didn’t think any of my readings seemed right. I am sending CPUA board and IOD board for repair. I will update when I get them back. The help is very much appreciated

You sure you weren’t taking resistance readings with power on? Only reason I can think that would cause changing resistance.