Need some help in troubleshooting instructions

[mellospace]

I'm trying to follow some troubleshooting directions from a manual, and I dont know how to do step #6 from the list. Can I perform this step without the HDS? Maybe with a regular OBDII scanner? Do I need to jump pins in the DLC Connector? Any help highly appreciate it. Just trying to troubleshoot my F-Can communication. Thanks.

#1. Turn the ignition switch OFF.
#2. Remove the gauge control module.
#3. Disconnect the gauge module 30P connector.
#4. Disconnect the ABS/TCS control unit 47P connector.
#5. If equipped with the Honda navigation system, disconnect the navigation unit 20P connector.
#6. Jump the SCS line with the HDS.
#7 Disconnect ECM/PCM connector A (31P).

[Fredsvt]

There is a way around that, but what are you trying to do in the first place? Curious.

[mellospace]

Originally Posted by Fredsvt

There is a way around that, but what are you trying to do in the first place? Curious.

I had an electrical mishap and I got F-Can communication error (TCS-ECM), abs, tcs, brake light on all the time when ignition on and when engine start, they never go off. Also, the TCS Activation indicator doesn't go on when in ignition on or at anytime. I've been driving with those lights for like 3 weeks, everything works fine. I believe I fried the ABS Modulator, but just want to check the F-Can communication first to make sure I don't have a broken wire or anything. I already checked all the power/ground and signal at the ABS Connector and everything is fine. I scanned the ABS but got the no communication with abs module from the scanner. I only got this U0021/U0055/U0073 error on the ECM. If you can let me know the way around it, that will really help since I just need to do this check before buying a replacement abs modulator. Why does this step need to be done? What's the purpose of it? Thanks.

[Fredsvt]

To manually jump the scs line, you need to jumper pins 4 and 9 on the dlc.

Do you have U0073, U0121, and U0155? I can't find the 0021 or 0055.

It's saying the fast CAN bus is off line.

The whole purpose of this is to make sure none of the bus lines are shorted to each other or to ground.

Have you gotten any B codes? Since the ABS/TCS is dead for now, we can't get any codes out of it.

Before doing anything, unplug the ABS/TCS connector, and then rescan the car. Clear the codes and see if your CAN codes go away. You should get no comm codes with the ABS/TCS module, but the network should be active.

I'm surprised that the gauges are working with the network compromised.

What did you do, if you don't mind me asking to possibly pop the module?

[mellospace]

Originally Posted by Fredsvt

To manually jump the scs line, you need to jumper pins 4 and 9 on the dlc.

Do you have U0073, U0121, and U0155? I can't find the 0021 or 0055.

It's saying the fast CAN bus is off line.

The whole purpose of this is to make sure none of the bus lines are shorted to each other or to ground.

Have you gotten any B codes? Since the ABS/TCS is dead for now, we can't get any codes out of it.

Before doing anything, unplug the ABS/TCS connector, and then rescan the car. Clear the codes and see if your CAN codes go away. You should get no comm codes with the ABS/TCS module, but the network should be active.

I'm surprised that the gauges are working with the network compromised.

What did you do, if you don't mind me asking to possibly pop the module?

Yes, you are right about the codes. They are U0073, U0121, and U0155. Those are the only codes I got, I actually got them from the dealer diagnostic. At first, I tried it with a Modis Snap On scanner and got the code U0121 alone and the "no communication with ABS Module", but the scanner couldn't delete the code. I don't even have the CEL on, only the ABS, TCS, BRAKE. So I decided to take it to the dealer for diagnostic and they got codes U0121, U0155 and U0073 and the no communication from ABS so they couldnt get anything there. They told me that either I have a short somewhere in the communication line or the ABS module is bad, but for then to continue checking the communication line circuit, that I will be charged extra $200 so I decided to do the checking myself. The thing is that when I use a regular OBDII scanner like the autozone one, I get no code whatsoever, not even the U codes so I don't know if doing the unplugging of the ABS connector will do any difference since I get no codes anyways. Only the Snap on got the code U0121 and the dealer got the others. Everything seems to work fine, I haven't lost my speedo or anything else on the dash meter or lights, the navi trip computer also works fine. Everything is functioning fine, except the ABS so my belief is that the module is bad and just want to make sure by doing the CAN line check.

Thanks a lot for your help. I'll try to do the check tomorrow or Friday.

[Fredsvt]

A regular obd2 scanner (global) won't read U B or C codes for the most part.

I doubt connecting the battery backwards will damage the communication lines, it could have melted something in the ABS computer, which then can make it throw all those codes.

I haven't researched, but you may want to see if there's a place that can just rebuild the computer part of the modulator. It should unbolt. Or, if you can find a used modulator and just swap over the electronics. The used one must be the exact part number of yours, as Honda uses different modulators for most of the different Accords.

[mellospace]

Originally Posted by Fredsvt

A regular obd2 scanner (global) won't read U B or C codes for the most part.

I doubt connecting the battery backwards will damage the communication lines, it could have melted something in the ABS computer, which then can make it throw all those codes.

I haven't researched, but you may want to see if there's a place that can just rebuild the computer part of the modulator. It should unbolt. Or, if you can find a used modulator and just swap over the electronics. The used one must be the exact part number of yours, as Honda uses different modulators for most of the different Accords.

Ok, thanks. Yes, I believe the same about something melted in the ABS computer. I already ordered a used ABS modulator (computer/pump) from a junkyard. It comes from the same car 05 Accord V6 so everything should work fine, I hope. Again, thank you for your help and I'll update on how everything goes after replacing the ABS computer.

[Fredsvt]

You will need to perform the TCS pressure sensor neutral position memorization with the new computer.

[mellospace]

Originally Posted by Fredsvt

You will need to perform the TCS pressure sensor neutral position memorization with the new computer.

I think I'll take it to the dealer so they can install it. I think it will cost 1 hr of labor so around $100 for the work. I'm very handy at troubleshooting the electronics and stuff, but not at doing mechanic work. Also, I thought the abs computer replacement needed to be programmed in some way to communicate with the ECM and the brakes to be bled, no?

Or is it just take off the old one and put the replacement one in, nothing else?

[Fredsvt]

I'm not sure that the dealer will just replace the electronic part of the modulator, as they (Honda) doesn't sell the computer separately from the whole modulator. (as best as I can tell) So I don't know if your local dealer will refuse to do it due to liability concerns.

You may have to do it yourself. There should be no interaction with fluid, but I've never taken apart one of these in that way. Many Ford and GM integrated modulators have removable electronic modules. You just have to be careful to remove it without banging it around as the electromagnets for the valves are in the electronic section on many of them.

As long as the used part you have has the EXACT part number of your old one, there should be no programming involved, other than following the position memorization I mentioned.

[mellospace]

Originally Posted by Fredsvt

I'm not sure that the dealer will just replace the electronic part of the modulator, as they (Honda) doesn't sell the computer separately from the whole modulator. (as best as I can tell) So I don't know if your local dealer will refuse to do it due to liability concerns.

You may have to do it yourself. There should be no interaction with fluid, but I've never taken apart one of these in that way. Many Ford and GM integrated modulators have removable electronic modules. You just have to be careful to remove it without banging it around as the electromagnets for the valves are in the electronic section on many of them.

As long as the used part you have has the EXACT part number of your old one, there should be no programming involved, other than following the position memorization I mentioned.

The part I bought it's the complete part with the computer and the pump together (modulator assembly) so I'm going to replace the whole unit. I thought the dealer could just do the replacement. Take off the old one and put the new one and charge me for the labor. But I thought it needed some programming thats why I thought about taking to the dealer. But if it's that easy, I guess I can just try to do it myself following this directions from alldata HERE. It says I need to bleed the brakes, do I need to get brake fluid for that process?

Also, the TCS pressure sensor neutral position memorization is HERE. I guess I can do that myself also.

[Fredsvt]

Yes, you can replace it yourself, if you're replacing the whole thing too.

You will need at least a couple of quarts of fluid to make sure it's fully bled.

Once you put the unit on, open the LF bleeder and wait until the fluid starts dripping out on its own. Let at least a 1/4 of the reservoir run through. Then do the RF, LR, RR.

Once you've done that, have someone help you and pump the pedal up. Open the left front..... close, pump up again (do the same wheel 3 times)........ Do each wheel in the same order 3 times each. Then repeat the rears twice with the parking brake on, and once again with parking brake off.

In the procedure they have for the position memorization, replace the HDS with a jumper on pins 4 and 9 on the dlc.

Now do the memorization procedure.

Drive the car, and activate the ABS several times. Make sure the pedal is ok, you may have to bleed them again.

[mellospace]

Originally Posted by Fredsvt

Yes, you can replace it yourself, if you're replacing the whole thing too.

You will need at least a couple of quarts of fluid to make sure it's fully bled.

Once you put the unit on, open the LF bleeder and wait until the fluid starts dripping out on its own. Let at least a 1/4 of the reservoir run through. Then do the RF, LR, RR.

Once you've done that, have someone help you and pump the pedal up. Open the left front..... close, pump up again (do the same wheel 3 times)........ Do each wheel in the same order 3 times each. Then repeat the rears twice with the parking brake on, and once again with parking brake off.

In the procedure they have for the position memorization, replace the HDS with a jumper on pins 4 and 9 on the dlc.

Now do the memorization procedure.

Drive the car, and activate the ABS several times. Make sure the pedal is ok, you may have to bleed them again.

Ok, thanks a lot Fred. I'll try to do it this weekend. I'll update you on how everything went. Thank you very much for being so helpful.

[mellospace]

Hey Fred, sorry to bother you again. But I just got to install the new (actually used) abs that I got to replace my other one, but it didn't fix the problem. I'm not even sure if that abs module that I bought from a Junkyard is really good (how can you check that). It didn't change anything in the car, same lights ABS, TCS and Brake and they come right away after key on the "ON" position and never goes off. It's like it didn't change anything in the car.

Do you think I should try to return that ABS module and get another one from the Junkyard and try it since it comes with 6 month warranty? or Do you think the problem lies on the ECM computer or somewhere else? Like i said previously, everything else works fine except this. Let me know what you think. I'm really running out of options with this problem.

And again, thank you for your help.

[Fredsvt]

Have you been able to scan the ABS module you installed? I'd be scanning the PCM, the gauge cluster.

The ABS/TCS module should give you a two digit code.

I'm looking at my book, it's being conflicted, it says in one place if the CAN com lines are down, it should only have the TCS triangle and TCS lights on. This is when the ABS module detects a com fault.

However, when the gauge cluster detects a failure in the com lines to the ABS, the brake light is added to the mix.

I'm seeing two com lines into the cluster from the ABS, NAV and PCM. I believe you've said that it is talking ok to the PCM and NAV. Does the NAV unit's trip computer function properly? Can you run the nav units internal diagnostics? It will test the FCAN system.

So far what I'm seeing, the cluster is the CAN bus controller. (the one that sends/receives all the CAN signals and sends them where they need to go)

Do you have anyone near you that owns another '05? I'd try swapping out the cluster to see if the codes go away.