Need some help in troubleshooting instructions [Archive] - Drive Accord Honda Forums

: Need some help in troubleshooting instructions


mellospace
10-12-2009, 02:55 PM
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
10-12-2009, 04:04 PM
There is a way around that, but what are you trying to do in the first place? Curious.

mellospace
10-12-2009, 06:28 PM
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
10-13-2009, 05:31 PM
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
10-13-2009, 07:16 PM
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
10-14-2009, 02:58 PM
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
10-14-2009, 03:34 PM
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
10-14-2009, 04:01 PM
You will need to perform the TCS pressure sensor neutral position memorization with the new computer.

mellospace
10-14-2009, 04:43 PM
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
10-14-2009, 04:55 PM
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
10-14-2009, 05:00 PM
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 (http://www.alldatadiy.com/alldata/AFI~G~C40355~R0~OD~N/0/41746505/41746506/41746536/41746537/34853741/34861870/92093563/56242970/14464382). 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 (http://www.alldatadiy.com/alldata/AFI~G~C40355~R0~OD2~N/0/108596970/110689023/110689028/110689032/34853741/92093625/92093627/56248244/56248264). I guess I can do that myself also.

Fredsvt
10-14-2009, 05:18 PM
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
10-14-2009, 05:21 PM
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
10-22-2009, 02:13 PM
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
10-22-2009, 04:02 PM
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.

mellospace
10-22-2009, 04:40 PM
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.

I have not scanned the ABS since I just installed it today, I guess I can try to do it on Saturday. Yes, terminal #23 and #24 on the gauge cluster connector are the ones for the communication lines. The Nav's trip computer does work properly. I run the self diagnostic on the gauge cluster (beeper drive circuit, indicator check, lcd check, gauge drive circuit check, comm line check) and I get no error there. Everything comes out fine during this test. How do I do a self test on the Nav to see if I get an error on the FCAN system? I have a friend with an '05 but his is a 4cyl without navigation, would that make difference or will the cluster be the same for 4 and 6cyl? Thanks.

Update: I checked the part # on the honda estore site for the meter for the 4 and 6cyl and they are different so I guess I won't be able to use his meter on my car.

Fredsvt
10-22-2009, 05:29 PM
Do you have a Helm's manual for your car?
I looked it over for the NAV system, it's very involved as far as what buttons to push, etc.

To get to the diag screen:

Press and hold "menu", "map/guide" and "cancel" for 3 seconds. (ONLY if battery has NOT been disconnected)

If the battery has been disconnected, hold down menu and zoom out at the code or GPS acquire screen. It should say navi system link push the joystick up to go to the functional setup menu. Push return, to get to select diagnosis.

Then select the item you wish to check.

Beyond that I don't have the fingers to type out all of the details. There's pages upon pages of it.

It may be worth it to pay the $10 for the three day subscription to Honda's Service Express site to be able to print out all the navi, CAN and ABS/TCS information.

mellospace
10-22-2009, 05:33 PM
Do you have a Helm's manual for your car?
I looked it over for the NAV system, it's very involved as far as what buttons to push, etc.

To get to the diag screen:

Press and hold "menu", "map/guide" and "cancel" for 3 seconds. (ONLY if battery has NOT been disconnected)

If the battery has been disconnected, hold down menu and zoom out at the code or GPS acquire screen. It should say navi system link push the joystick up to go to the functional setup menu. Push return, to get to select diagnosis.

Then select the item you wish to check.

Beyond that I don't have the fingers to type out all of the details. There's pages upon pages of it.

It may be worth it to pay the $10 for the three day subscription to Honda's Service Express site to be able to print out all the navi, CAN and ABS/TCS information.

Ok, thanks. I think I'm gonna look it up at alldata and see what I find. I guess I'll try what I can tomorrow and everything else as scanning the abs on Saturday.

donaldos
11-10-2009, 10:05 AM
was there ever a resolution to this problem, it turns out I have the same issue.

mellospace
11-16-2009, 11:26 AM
was there ever a resolution to this problem, it turns out I have the same issue.

No, I still got the problem. I scanned it again after replacing the abs module and still got the no communication error.

I checked everything Fred told me to check and everything seems fine. I got the communication to the Navi Trip computer check good (Navi diagnostic), the gauge check good (through the gauge diagnostic). The only thing left to try is exchange the gauge or the ECM from another accord which I do not have available so I just left it alone for now since I have no choice and don't want to spend more money buying parts to try them. I don't know. I'm thinking I'm gonna check the speed sensors which are the next cheapest option to fix the problem, maybe that is actually causing the problem, who knows, not sure if that can cause the communication problem, but still my speedo works so probably that is not the problem.

How the problem started in your car? did anything happen to your car before the lights came out for you?

donaldos
11-19-2009, 08:53 PM
I had a short after installing a ndvo to the navigation system, funny thing is that I can use the aux input, but now I have a different problem. My car hasn't reach the miles that the extended warranty covers, I might take it to the dealer, most of the time this things are not covered, but will let you know. Thanks!

mellospace
11-23-2009, 01:15 PM
I had a short after installing a ndvo to the navigation system, funny thing is that I can use the aux input, but now I have a different problem. My car hasn't reach the miles that the extended warranty covers, I might take it to the dealer, most of the time this things are not covered, but will let you know. Thanks!

Ok. Please update on how it goes at the dealer. Thanks.

donaldos
12-06-2009, 11:46 AM
hi, you know after reading this tread I figured the abs module was not the problem and decided to change the cluster but that was not the problem, since i don't have a computer to read abs codes on a honda, finally took it to the dealer. I took them about 1 hour of diagnostics and 3 hours to change the abs/tcs module and the lights are gone, i'm pretty sure you can try to get another module, i've seen them in e-bay, the problem is that we don't know for sure if they are ok. the repair cost was covered under warranty at the dealer. good luck!::thmsup:

mellospace
12-07-2009, 05:47 AM
hi, you know after reading this tread I figured the abs module was not the problem and decided to change the cluster but that was not the problem, since i don't have a computer to read abs codes on a honda, finally took it to the dealer. I took them about 1 hour of diagnostics and 3 hours to change the abs/tcs module and the lights are gone, i'm pretty sure you can try to get another module, i've seen them in e-bay, the problem is that we don't know for sure if they are ok. the repair cost was covered under warranty at the dealer. good luck!::thmsup:

Ok, I guess I'll ask the junkyard to replace the module I bought from them (6 month warrantly) and see how it goes. Thanks for the update.