Member Since: 21 Oct 2016
Location: kent
Posts: 14177
Hi mate
Many thks and indeed looks like the alternator is stuffed as it’s producing around 14 odd volts and then once the load is on it drops which of course it shouldn’t do
Apologies as wasn’t sure how much access would be possible to it
Have read a lot about only getting a Denso alternator
Don’t know how hard they are to change , plus u could always get it tested out by halfords or a electrical company to double the verification of the figures so then it’s 100% as would hate for u to change it if it’s something like the wire , connector on the back of the alternator , which by the sounds of it needs to come out in order for u to reach them so I suppose if that’s the case I would be tempted to change it anyway
Awesome ref the wipers , Plse let me know how u get on and fingers crossed that’s the only thing and replacing the alternator will resolve the issue once and for all
Can of course find some guides etc if I wish to change be it urself
Hope that helps
6th Mar 2021 7:09 pm
TyphoonDisco
Member Since: 18 Jan 2021
Location: Morpeth
Posts: 102
Hi Gary,
I might give it a crack myself, I think I will need to take a load more bits out of the way from above to gain access. It's only 3 bolts holding the alternator on and then the wires/connector. Not sure if I need to make a detensioner to release the belts though.
A new Denso is about £210 which isn't too bad. Fingers crossed that will sort it. If it's not that I will be stumped!
I'll have a search for some tutorials to change it.
6th Mar 2021 7:28 pm
TyphoonDisco
Member Since: 18 Jan 2021
Location: Morpeth
Posts: 102
Ok. I've ordered a brand new Denso alternator, some viscous fan spanners and a new drive belt.
Even if this doesn't fix the issue I think the alternator needed done anyway. It looks to be original to the vehicle (11 yrs old).
I'll keep you posted Gary!
6th Mar 2021 8:59 pm
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 14177
Hiya
That’s brilliant and indeed fingers crossed will sort out the issues , plus an opportunity to check the connectors etc , that’s a great idea doing the belt at the same time , at least then u know it’s done
Had a good search and found this video which I hope helps , of course know ur not daft and that it doesn’t come across as rude but just plse ensure u remove the battery leads first along with axle stands
Must admit did buy some plastic ramps which I’ve found very useful , plus just thought might be best before disconnecting ur battery to raise the suspension to off road height to give u some more room
Many thks and indeed Plse let us know how u get on
7th Mar 2021 6:38 am
TyphoonDisco
Member Since: 18 Jan 2021
Location: Morpeth
Posts: 102
Well I'm afraid to report I am still no further forward.
I've fitted a brand new Denso alternator (which in the end wasn't too bad a job). This has resulted in slightly higher idling voltages, less drop when I load up the electrics and it also seems to have done away with the intermittent dips in voltage with the change in engine tone.
That's the good news.
The bad news is the fault still came back after sitting idling for about 20 minutes. I also note the repetitive clicking of RELAY 4 is still there every 15 seconds or so. I should add that I have replaced this with a brand new LR relay so it's not the relay at fault.
I am now at my wits end. Whatever is causing the issue isn't leaving a fault code apart from the U0122 codes listed below when the CANBUS trips off.
I don't know why RELAY 4 is clicking every 15 seconds. It would be great if someone could tell me if this is normal behaviour. Because RELAY 4 is for the heated mirrors and washers I was thinking it could be clicking because they have reached the required temperature and the clicking is the system checking whether it needs to energise again to heat up.
Anyway, I don't know where to look next. It's driving me mad.
I've copied the U0122 codes in case it helps...
VIN: SALLAAA139A511904
L319 - Discovery 3 2009
Vehicle scanned on 12-03-2021 18:00
Using IIDTool BT V4.0 B2691
Airbag
U0122-87 (2C) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 12-03-2021 17:59:27 at 100863 mi )
Parking Brake
U0122-87 (B8) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 12-03-2021 17:59:24 at 100863 mi )
Steering Angle
U0122-87 (6C) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 12-03-2021 17:59:28 at 100863 mi )
Suspension
U0122-87 (2E) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 12-03-2021 17:59:25 at 100863 mi )
Terrain Response
U0122-87 (2C) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 12-03-2021 17:59:25 at 100863 mi )
Transfer Case
U0122-87 (2C) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 12-03-2021 17:59:24 at 100863 mi )
12th Mar 2021 6:32 pm
TyphoonDisco
Member Since: 18 Jan 2021
Location: Morpeth
Posts: 102
Regarding the repetitive clicking RELAY 4.
When I measure the voltage at the relay using the MM I can see that it is powering for 15 seconds at 14.2vDC and then switching power off for 15 seconds and so on.
This is when measuring the following 2 points:
- The horizontal blade nearest the windscreen (let's call this the top blade)
- The vertical bottom right blade
When I measure the other 2 blades:
- The horizontal one below the top blade
- The vertical bottom left blade
I get a constant 14.2vDC which I can isolate by removing BOTH fuse 12 and fuse 16. Replacing either fuse reinstates the 14.2vDC at those points.
Now the final bit is I get continuity between the top blade and the bottom left blade. Surely this means it is trying to short itself every time the top blade energises every 15 seconds?
I hope this all makes sense but please let me know if you want me to expand or take some pics.
13th Mar 2021 4:44 pm
TyphoonDisco
Member Since: 18 Jan 2021
Location: Morpeth
Posts: 102
Looking at this thread copied below it appears the on/off functionality of the heated mirrors is correct. 50% on and 50% off which might explain the 15 seconds on and 15 seconds off??
Exterior Mirrors
Heating
The CJB receives the ambient air temperature value from the ECM (engine control module) on the high speed CAN (controller area network) bus. The CJB converts the ambient air temperature value to an on-time percentage and transmits it on the medium speed CAN bus to the two door modules, which then energize the exterior mirror heating elements accordingly. The on-time percentage is increased while the windshield wipers are on.
Click image to enlarge
13th Mar 2021 5:12 pm
TyphoonDisco
Member Since: 18 Jan 2021
Location: Morpeth
Posts: 102
So I think the heated mirrors are working as advertised and RELAY 4 is clicking correctly as it's indicating the cycle of power off to power on 50% of the time. This is controlled by the ATCM.
I guess that means I am back to square one!
I am still getting the random failure which can come on with either just the ignition or with the engine running either stationary or moving. No actual fault codes but just a load of U0122 lost comms codes.
I give up!
13th Mar 2021 5:55 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 5069
As I said in an earlier post I'm not convinced this relay/heated door mirror issue is at the root of your problem. Mainly because the COMS errors are not on the same systems, and most of them are cascade errors due to the "actual" COMS fault. I would again suggest you drop this line if investigation and concentrate on the dtc related cabling and connectors.
Looking at the dtc's it "appears" the initial failure is either at the parking brake, or the transfer case wiring, though not necessarily!
As I pointed to earlier, the most common area for wiring failure related to your issue is at the large block terminal on the n/s/r chassis rail. I know you have had a look, but look again! You need to start somewhere, so strip the outer sheath well back particularly in the direction of the boot floor grommet where the cables pass through. Then the sheath on the other side of the terminal connectors.
If there is nothing obvious check the wiring and connections on the transmission/transfer case. If still no joy you may have to test each cable one by one via the wiring diagram. yµ (idµ - eAµ) ψ=mψ
13th Mar 2021 6:31 pm
TyphoonDisco
Member Since: 18 Jan 2021
Location: Morpeth
Posts: 102
Hi Prof,
Thank you for the response! I will get into that loom again in the NSR arch. When I was under the rear with the spare wheel dropped it also allowed access to the those wires and it's easier than removing the wheel and liner.
Tonight I've been playing around with the GAP IID BT and I selected "pending" faults as an option. When the fault came on the list of codes looked like this. Note the timings of the Instrument Cluster fault. I did this process twice and both times it showed as approx 30-35 seconds earlier.
Also, most of the mileages below are 100864 whereas the instrument cluster one is 100865 and my actual odometer in the cluster reads 100887.
Would all of this point towards an instrument cluster issue?
I've already had it out of the dash and the connections all seem good. Is there anywhere else that is prone to water/fraying before it reaches the instrument cluster?
VIN: SALLAAA139A511904
L319 - Discovery 3 2009
Vehicle scanned on 13-03-2021 18:57
Using IIDTool BT V4.0 B2691
Airbag
U0122-87 (AF) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 13-03-2021 18:56:07 at 100864 mi )
Instrument Pack
U0122-87 (27) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 13-03-2021 18:55:33 at 100865 mi )
Parking Brake
U0122-87 (EB) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 13-03-2021 18:56:05 at 100864 mi )
Steering Angle
U0122-87 (2F) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 13-03-2021 18:56:09 at 100864 mi )
Suspension
U0122-87 (AF) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 13-03-2021 18:56:06 at 100864 mi )
Terrain Response
U0122-87 (2F) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 13-03-2021 18:56:06 at 100864 mi )
Transfer Case
U0122-87 (2F) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 13-03-2021 18:56:05 at 100864 mi )
Transmission
U0122-87 (27) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 13-03-2021 18:56:05 at 100864 mi )
13th Mar 2021 7:11 pm
TyphoonDisco
Member Since: 18 Jan 2021
Location: Morpeth
Posts: 102
I should add that my fault is always accompanied by the speedo falling to zero and the odometer not counting up.
Not sure if this is just because the instrument cluster is being tripped off as part of the BUS failure or if the instrument cluster is the actual cause of the issue.
13th Mar 2021 7:31 pm
aja4x4
Member Since: 14 Apr 2019
Location: Westbury
Posts: 2463
Sounds like a cluster faultAndrew
D3 2.7tdv6 2005
D4 3.0 SDV6 Commercial died and gone to LR heaven
D5 3.0 SDV6 HSE
13th Mar 2021 7:42 pm
TyphoonDisco
Member Since: 18 Jan 2021
Location: Morpeth
Posts: 102
Thanks AJA,
I've just been out to it and pulled the cluster out again. The connector looks clean as a pin and it doesn't trip the fault when moving the connector/loom so I think it's likely the dry solder issue or something else amiss inside the cluster.
When I removed the back cover it looked like all the circuitboard was in good order but have a look at the inside of the rear cover...
13th Mar 2021 7:58 pm
TyphoonDisco
Member Since: 18 Jan 2021
Location: Morpeth
Posts: 102
It's covered in strange wormy type formations of dust. It wipes off easily with a cloth/finger. I wonder if this is just the electromagnetic forces affecting the formation of the dust.
Are there any diagnostics I can carry out to further investigate the cluster or should I bite the bullet and send it off for a refurb? Any recommendations?
Thanks again.
13th Mar 2021 8:01 pm
aja4x4
Member Since: 14 Apr 2019
Location: Westbury
Posts: 2463
I would send it away for repair at least you know it is good when you get it backAndrew
D3 2.7tdv6 2005
D4 3.0 SDV6 Commercial died and gone to LR heaven
D5 3.0 SDV6 HSE
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