- You are currently viewing DISCO4.COM as a guest - Register to take part or Log In
arez
Member Since: 04 Feb 2021
Location: Hernes
Posts: 9
  
|
| Problems. Bus signal/message failure - missing a message |
|
Hi.
This summer the car started to act up sometimes. The Instrumentpanel lit up like a christmas tree. ABS, Parkingbrake, Transfer case, transmission and so forth. After a restart it kind of sorted it self but as of recently it has become more of a permanent issue.
The fault codes generated by the Iidtool looks like this:
Model L319 - Discovery 3 2005
Vehicle scanned on 23. des. 2022 09:54:02
IIDControl 3.0.4 Build 90 Android - IIDTool BT V4.0 B2742
Airbag
U0122-87 (AF) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 08-10-2026 23:16:36 at 317102 km )
Body Control
B1C14-3A (2E) Driver's left/right mirror motor feedback circuit - Frequency modulation/pulse width modulation failure - incorrect, has too many pulses
( on 12-10-2026 10:20:44 at 317094 km )
Engine TDV6
U0121-00 (2F) Lost communication with ABS control module
P1935-00 (2F) Brake switch/sensor signal
P1934-00 (2F) Vehicle speed signal
Instrument Pack
U0122-87 (2F) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 19-05-2040 03:15:37 at 317102 km )
Parking Brake
U0122-87 (EB) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 08-10-2026 23:16:43 at 317102 km )
Steering Angle
U0122-87 (2F) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 08-10-2026 23:16:47 at 317102 km )
Suspension
U0122-87 (AF) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 08-10-2026 23:16:45 at 317102 km )
Terrain Response
U0122-87 (2F) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 08-10-2026 23:16:44 at 317102 km )
Transfer Case
U0122-87 (2F) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 08-10-2026 23:16:47 at 317102 km )
Transmission
U0122-87 (AF) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 08-10-2026 23:16:45 at 317102 km )
The time and date stamp looks totally f***ed up too. 
So far I have changed the battery from a cheap one to an Exide, charged it to max with my C-tek charger, cleaned the terminals. Switched the transfer case module between two cars, checked the connector for the epb behind the rear left wheel and wiggled the wires.
Tomorrow I get to use a garage with a lift so I can get underneath and check further on ground points and connectors. I will also check the resistance between Can high and low (pin 6 and 14 on the obd) and between 6 and ground and 14 and ground. I don't have a scope so checking with a MM is what I can do.
If anyone has some more pointers on what I should do I will be very grateful for som input.
Kind regards.
|
 6th Jan 2023 10:49 am |
|
|
Globetrotter448
Member Since: 21 Mar 2017
Location: Londonderry NSW
Posts: 1807
|
"U" codes are information codes. I firstly would check your battery voltage as it may be a battery problem. Everything switched off, battery should show at least 12.4 volts, if not, recharge or replace, when first started battery should show around 14.4 volts, this indicates that the alternator should be okay. This is where I would start.
|
| 7th Jan 2023 5:39 am |
|
|
Flatlander
Member Since: 20 Jul 2015
Location: Here
Posts: 575
|
It looks like the ABS is the root cause - look at the DTC's stored in the ECM.
'U' codes are communication codes, a lot of people say discount them but they can be useful in pointing to lost comms.
There is a DTC there for brake pedal switch, I'd start by checking the brake light bulbs for loose filaments or incorrect items - also if OK I'd replace the brake pedal switch as a 'usual suspect'. The vehicle dynamics control module cannot function properly if the ABS is not broadcasting information about the brake pedal switch or the composite vehicle speed. It is strange that there are no ABS DTC's though...
|
| 7th Jan 2023 8:26 am |
|
|
arez
Member Since: 04 Feb 2021
Location: Hernes
Posts: 9
|
The brake pedal switch is brand new. Original LR part too.
When the car suddenly started working yesterday and I could erase the faults I had signal på all wheel speed sensors, steering angle, and brake switch. When I have the missing signal error i don't get any live values from the high speed can network.
That is what puzzles me sinse the steering angle and brake switch are the only P faults I get when I scan for faults during the instrument panel light orgy.
After the car suddenly started working again yesterday we took it for a long test drive, to try and provoke the error to return. We tried everyting, hard braking to engage abs. Low series, terrain response programs, command shift, disabling dsc, a bit of offroading in loose snow to really test the terrain respone and everything worked just fine. Drove home and later the same evening went out to start the car. Put the key in the ignition. turned the ignition og and started the car and the light orgy started up way befor the glowing was done. Turned off the car and didn't touch it again until this morning.
Repeated the prosedure from last night. Just key in ignition, turned it on and started the car and everything was just fine again.
I think the bloody thing is possessed.
|
| 8th Jan 2023 12:26 pm |
|
|
Flatlander
Member Since: 20 Jul 2015
Location: Here
Posts: 575
|
Check the power supply to the ABS, also check pin grip on the +ve & -ve connections at the ABS, it could well not be storing faults because it is 'off' (as in not powered up sufficiently) which would explain the lack of live values.
Next time it faults, if you can, disconnect the battery and measure the resistance of the HS CAN at the diagnostic socket, you're looking for either 120 or 60 Ohms. I doubt it will be 120 Ohms as there are no DTC's stored in the ABS, but you never know...
|
| 8th Jan 2023 3:28 pm |
|
|
arez
Member Since: 04 Feb 2021
Location: Hernes
Posts: 9
|
Managed to find my good MM and have taken som quick measurements in the horrible weather.
Voltage on Can High with engine running and active fault: 6,8V way too high
Voltage on Can Low with engine running and active fault: 6,5V also way too high
Voltage on Can High with ignition off is 0,8V
Voltage on Can Low with ignition off is 0,7V
Resistance between can high and low is 60.1 ohm. Battery disconnected. That should be spot on.
Resistance between can high and ground is open loop.
Resistance between can low and ground is open loop.
|
| 8th Jan 2023 5:36 pm |
|
|
Flatlander
Member Since: 20 Jul 2015
Location: Here
Posts: 575
|
Where are you measuring those CAN voltages between? those voltages on a voltmeter just indicate lots of activity, you'd need to 'scope them to check actual voltage. In any case, if CAN voltage was too high, there'd be lots of other failures and DTC's.
Did you check the connections to the ABS? there are term.30 & term.15 supplies.
You're correct, CAN is intact with ~60 Ohms loop resistance.
|
| 8th Jan 2023 7:26 pm |
|
|
arez
Member Since: 04 Feb 2021
Location: Hernes
Posts: 9
|
Didn't check the ABS. It was raining cats and dogs last night so I didn't want to do anything that required the bonnet to stay open. I will check it out as soon as possible.
Thanks for taking the time to give me some pointers. 
|
| 9th Jan 2023 7:45 am |
|
|
arez
Member Since: 04 Feb 2021
Location: Hernes
Posts: 9
|
Flatlander wrote:Check the power supply to the ABS, also check pin grip on the +ve & -ve connections at the ABS, it could well not be storing faults because it is 'off' (as in not powered up sufficiently) which would explain the lack of live values.
Next time it faults, if you can, disconnect the battery and measure the resistance of the HS CAN at the diagnostic socket, you're looking for either 120 or 60 Ohms. I doubt it will be 120 Ohms as there are no DTC's stored in the ABS, but you never know...
I think I've fixed it. The bad weather has hindered me in working on the car but your comment on the ABS tickled me a bit.
So I decided to look in to it inside. Since I knew whitch warninglight I had in the IC i wrote those up in an excel. Then I matched the lights with the faults read on the gap tool. Started to reverse my thinking a bit and thought perhaps the fault given on missing signal was actually in perfect order. Then I started looking on what kind of signal they wanted and I traced it back to the ABS. After systemizing it, I had the warning light but no faults or proof of any other signal sent from it.
Yesterday the weather permitted me to go outside to do a bit of work on the car and I took the connector from the unit and took it apart. Cleaned out everything with oxice clean several times and brushed everything with a tootbrush I adapted. Put it back together and wiggled it a bit back and forth. Took it apart again, blew it dry and sprayed it with contact spray. Assembled everything and connected the battery and everything has been working perfectly since.
Took the car for a 70km test run and put the abs through it's paces with hard locking, spinning the wheels with and witout dsc etc. Worked perfectly the whole time.
So I might be a bit premature but I think the problem is solved.
Thanks a lot for the help.
PS. Snow is falling heavy so today I'm gonna play in the snow again. Finally. 
|
| 15th Jan 2023 9:20 am |
|
|
|
Posting Rules
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
|
|
DISCO4.COM Copyright © 2004-2024 Futuranet Ltd & Martin Lewis
|
|
