Dash back light dims, warning lights come on.

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My Name: Ozvtr

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Posts: 1043
Joined: Wed Jul 10, 2019 3:31 am
Model: C3 2002-2005, Original shape model
Year: 2003 (53)
Engine Size: 1.4 (8v)
Fuel Type: Petrol
Mileage: 80000
Trim Level: Other
Gearbox: Automatic PRND
DPF: No
LHD or RHD: RHD
Engine name: TU3 (75 PS)
Location: Brisbane, Australia.
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Driving home from work yesterday (day time) the dash back light, fuel and temp indicator bars went dim. The temp indicator went to full hot (all the bars on). Most of the warning lamps came on, also dim. I could not tell you which warning lights were on and which were off but it seemed like most of them were on. There was also a single "ding" from the COM2000. I do not know if the dash displayed the speed or just a "0" (I was taken off guard). The engine ran fine and responded to throttle peddle inputs. I also noticed that the digital aircon panel had dropped out of "auto" and the compressor had been deactivated (no snowflake symbol). I did not have the radio on at the time.
The event lasted between 20 and 30 seconds (maybe less) after which all but the passenger airbag warning light returned to normal. The passenger air bag warning remained on until the engine was switched off and then restarted. After which everything functioned normally and the air bag light remained out.
Before I go on, no, I have not figured out what the failure is/was. Also I have not polled the car with the LEXIA. I don't believe anything it might tell me would be helpful. I expect a bunch of temporary system failures because of low supply voltage. Not really unexpected.
I initially suspected a relay or connector in the BSI.
Looking at the circuit diagrams shows there is a common power supply for the dash, air bags, radio and aircon. F14 in the BSI supplies all those circuits, either directly or indirectly (through another, sub fuse). But there is no relay in the circuit, at least not in the BSI. Power for that circuit comes from the BSM in the engine bay but the circuit diagrams don't show the BSM's internal power distribution (for that circuit).
So my suspects are; the F14 fuse holder (burnt out). A bad solder joint on the BSI PCB. The #3 contact in the green connector of the BSI (burnt out). Pin #9 of the 10 pin black connector on the BSM (burnt out). Bad solder joint in the BSM. Or some other unknown fault in the BSM (because the circuit diagram doesn't show anything inside there).
I shall try and keep you informed.
Of course, if anyone has seen this before and may have a clue, please chime in. :D
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My Name: Arfur Dent

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Posts: 3410
Joined: Sat Jul 23, 2011 3:47 pm
Model: C3 2002-2005, Original shape model
Year: 2002 (52)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 100000
Trim Level: Exclusive
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Engine name: DV4 16-valve diesel (90 PS)
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Hello Ozvtr

This sounds similar to a fault a few years ago. A temporary situation where the engine running unaffected but the dash display went wild.


After driving a few miles of local roads, the first thing I noticed was the lack of Speedo. But there were other strange things with the warning lights, enough to make me pull over to stop and think that it looked pretty serious.

Switch off ignition and restart engine cleared it.

I put it down to the bus locking up because after switching the ignition off and on the fault cleared and everything returned to normal.

The fault never came back over the years.


You may have VAN/CAN bus faults on lexia, but I don't think they will tell you why it went bad, just that it did go bad (but you know that anyway).
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User avatar
My Name: Ozvtr

Moderator
Posts: 1043
Joined: Wed Jul 10, 2019 3:31 am
Model: C3 2002-2005, Original shape model
Year: 2003 (53)
Engine Size: 1.4 (8v)
Fuel Type: Petrol
Mileage: 80000
Trim Level: Other
Gearbox: Automatic PRND
DPF: No
LHD or RHD: RHD
Engine name: TU3 (75 PS)
Location: Brisbane, Australia.
Has thanked: 44 times
Been thanked: 300 times

Post

Thanks for the comment.

I have checked the the connector in the BSM but the contacts there are fine. As you know inspecting the BSI connectors is a pain but I will eventually check it.

Hmm VAN bus fail is a possibility as the CAN bus items seemed to be unaffected however power loss may also cause BUS failure. The lights going dim though seems to lead me more towards power failure.

I'll check LEXIA and see what it says.
User avatar
My Name: Ozvtr

Moderator
Posts: 1043
Joined: Wed Jul 10, 2019 3:31 am
Model: C3 2002-2005, Original shape model
Year: 2003 (53)
Engine Size: 1.4 (8v)
Fuel Type: Petrol
Mileage: 80000
Trim Level: Other
Gearbox: Automatic PRND
DPF: No
LHD or RHD: RHD
Engine name: TU3 (75 PS)
Location: Brisbane, Australia.
Has thanked: 44 times
Been thanked: 300 times

Post

I've had a chance to scan the car but unfortunately it doesn't say much.
lexia_scan_global.jpg
It shows problems with the dash (instrument panel), the radio, air bag, central display and the engine ECU.
Ok, the radio always whinges that the signal strength is too weak! My C2 radio complains about that too but the radio works fine! Next! The central display seems to expect a permanent connection to the battery but funnily the BSI cuts the power to reduce the power consumption. Another non-event.
Lets get to the serious stuff. First the instrument panel.
lexia_scan_dash.jpg
Ah, the coolant thing! OK, I ran a few tests for a member here. He said his car wouldn't start because the coolant sensor was not working. So I disconnected the sensor and attempted to start the engine. It started! This coolant sensor error will pop up later too.
Hmm no comms with the BSI? This means that the cluster was still working but but not getting info from the BSI. Could this power outage have taken out the BSI as well? The comms between the BSI and the dash is on the comfort VAN BUS. However the aircon went out, it's on the comfort VAN too, but there is no error recorded?
airbag_scan.jpg
The airbag ECU is on the body VAN1 BUS so it's not just a single BUS failure. Looking more like a power failure. Also, there is no air bag de-activation switch in my car, so the thing has had a brain fart. Sounds like power failure again.
engine_scan.jpg
OK, so this is more of the coolant temperature sensor thing. As I said above, the engine seemed to be running fine, so we can forget these.
D'OH!!!!! I just realized that the temp gauge also went flat out with the "event". Should have looked at what the engine was doing at the time! I assumed too much! I'm not sure if one of these errors may be associated with the event!? Looking at the circuit diagram, the two wires only go to the engine ECU, so I'm doubtful they have anything to with the event. But I should have been more studious!
So what are we left with? I think it still looks like a power failure only. Not much further ahead. I think I will continue looking at the plugs and connectors?
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