480ES dash electrical problem

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andyb2000
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480ES dash electrical problem

Post by andyb2000 » Sun Nov 11, 2018 1:40 pm

Hi all,

I'm busy fixing up a "barn find" 480ES L reg (1994) and it's got a couple of strange electrical problems I'm working through.
(Am pretty competent with electrical systems, soldering, wiring, etc, as part of my job years back!)

The first, when ignition goes on I get a constant clacking from a relay(s) engaging and releasing. I've tracked them down to the two relays underneath the steering column in the cabin.
Image
https://imgur.com/a/GjGQvqP

That's them in-situ, pulling them out of their holder so I can get to them I found them both to be:
WEHRLE 20 210 032
PA6.6 - GF30
In standard 4-pin configuration (30,85,86,97). Both relays appear to be OK electrically but rattle away for a few minutes until they sort of give up and stop.
Whilst they're clacking away the green upside down Y (Lambda) bulb flickers in time with the relay rattle, so looks related to that system (self test?).
I'm also only reading 3v according to my multimeter at the fuel pump (which I've just replaced as was faulty) so I'm wondering if the other one is the fuel pump relay?

No fuses appear blown at all, so discounting all of those (Note that my entire infocentre is dead, not just backlight failure, so that'll be another job to take dash apart, reflow solder, etc, as per guides and other howto's on this excellent forum)

Quick video that shows the Y bulb flickering and you'll hear the relays in the background:
https://photos.app.goo.gl/FQc939QubikEYMi27

So - Does anyone have a definitive diagram for relays and fuses on this 1994 edition, as I've got a few relays in the engine bay in the triangle (no labels that I can see to tell you what is what), the fuses under the driverside compartment (in the cabin) are labelled but again unsure which is top and bottom as you look at them! Thirdly these two mysterious relays attached to the underneath of the steering column too.

Thanks in advance!
Thanks for all your help! - Andy
Volvo480 ES 2.0 petrol - 1994 (UK RHD L-reg)

Alan 480
480 Is my middle name
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Re: 480ES dash electrical problem

Post by Alan 480 » Wed Nov 14, 2018 6:51 pm

one is for th efuel pump, can't rememebr what the other is for!!! maybe ignition controlled circuits but I think ignition controlled is one of the units under plastic triangle. I can look at week-end when daylight to confirm which one is fuel, and make a stab at the other :-)

could the other be the 'heater' for the lambda sensor?
Alan

480 ES 2litre x 2, C30 1.8ES, SS1

Alan 480
480 Is my middle name
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Re: 480ES dash electrical problem

Post by Alan 480 » Sat Nov 17, 2018 7:43 pm

both of them are for 'fuel supply', tied together . . . .

the one nearest the centre of the car will deffo be supply oomph for the pump, if it is dead then NO fuel, you could pull the relay and confirm that the pump runs when ignition is turned on ?
Alan

480 ES 2litre x 2, C30 1.8ES, SS1

eye of ra
Can tell where the 480 was built
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Re: 480ES dash electrical problem

Post by eye of ra » Sun Nov 18, 2018 11:58 am

Alan 480 wrote:
Sat Nov 17, 2018 7:43 pm
both of them are for 'fuel supply', tied together . . . .
As usual with 480 wiring only on some models.

On the Turbo, F and E Fenix 1 they were.
Fenix 3.2, FP/EP and 2.0L they weren’t.
Current:
480 ES Auto 1989
480 ES Auto 1991
CLK430 Conv 2001
Hyundai i10 2015

ijw101
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Re: 480ES dash electrical problem

Post by ijw101 » Sun Nov 18, 2018 1:13 pm

The 1 is fuel pump and the other is fuel injection both controlled by the ecu. Mine would switch on then straight off again and it turned out to be the crank sensor, but mine wouldn't start. There are some circuit diagrams I down loaded.

andyb2000
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Re: 480ES dash electrical problem

Post by andyb2000 » Mon Nov 19, 2018 2:28 pm

Thanks for this folks. I've done quite a bit of work this weekend to trace it all and see whats going on. So far I've found the same as your findings:
1 relay is an ignition/supply to the Bosch ECU for injection/fuel control system (I've bought the paper copy Haynes manual and using the wiring diagrams at the back proved good here. My previous life involved in electronics has helped here!). So I've had the fuel system ECU out (Passenger compartment, passenger side, take glovebox and part of dash trim apart, then two screws hold it in place, 3 connectors. Once out I opened it up to check for water damage, dry joints, etc, and it looks in decent condition. So do the relays on-board, nothing amiss there but only did a few visual checks.

Checked and at ignition on 12v gets supplied to both relay coil contacts, so looks like the ECU is sending the right signal. Checked the output and by bridging the output relay I can fire the fuel pump up, so wiring there is good.
So that means it must be something else causing either the ECU to withdraw power from the relay or when the relay contacts are closed something is causing it to release again.
I'm thinking like you ijw101 that it might be crank sensor, etc, however when not cranking why would this impact the fuel pump? From testing the 12v is supplied for a short period on ignition on and if you don't start then the 12v gets withdrawn (As you'd expect so pump isn't priming system indefinitely). That seems to be working as expected, so to me it suggests the ECU isn't toast.
(PS: checked both relays and are both sound)

Alan - heater for lambda sensor is an interesting one, as I am getting lambda light flickering too, so I wonder if this is throwing the system off if it's fault, I'm thinking of disconnecting lambda sensors/wiring and trying again, slowly isolating circuits to test further. Going to go back to my electrical wiring diagrams and look for what else is involved in the circuit.

Thanks for the help so far guys, I'll go back and post more later.
Thanks for all your help! - Andy
Volvo480 ES 2.0 petrol - 1994 (UK RHD L-reg)

ijw101
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Re: 480ES dash electrical problem

Post by ijw101 » Mon Nov 19, 2018 3:35 pm

It's the CEM on the passenger side in a plastic case the ECU is in a metal case on the drivers side

eye of ra
Can tell where the 480 was built
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Re: 480ES dash electrical problem

Post by eye of ra » Mon Nov 19, 2018 6:30 pm

As ijw101 says it’s the CEM on the passenger side not the ECU but I think knowing what engine you have my help as originally you say 480ES 1994 which would make it a 2.0L however you now mention Bosch ECU for injection/fuel control system which would make it a 1.7 Turbo.

The wiring and how the two relays work is different between these two cars.
Current:
480 ES Auto 1989
480 ES Auto 1991
CLK430 Conv 2001
Hyundai i10 2015

ijw101
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Re: 480ES dash electrical problem

Post by ijw101 » Mon Nov 19, 2018 7:46 pm

I traced mine using resistance readings the crank sensor around 220 ohms the lambda around 15 ohms but my 1st move was earth connections and check the connections between sensors and pin layouts on cem and ecu. The lambda won't stop the car starting. My final electrical fault was the previous owner connected the coil wrong. The Haynes manual is OK but not as good as the download of the volvo green manual.

Alan 480
480 Is my middle name
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Re: 480ES dash electrical problem

Post by Alan 480 » Mon Nov 19, 2018 10:34 pm

regading this bit
######
12v is supplied for a short period on ignition on and if you don't start then the 12v gets withdrawn (As you'd expect so pump isn't priming system indefinitely). That seems to be working as expected, so to me it suggests the ECU isn't toast.

yep thats what ours does, short run to prime system then 'stops' I always wait until I hear this priming stop BEFORE i turn key to 'starter', just a habit . . ..

If I turn ign off then wait about five/ten seconds there is a 'click' off then when turn key again it 'reprimes' exact length of time to be confirmed for the pump run, wait pump re-run if it helps?

so it does sound as if the fuel pump is NOT a problem, if runs when supplied with a decent 12V supply ??

wonder where the 3V came from unless the on/off duty cyle just gave it 25%?

I'm also using the HBOL , but taken with a pinch of salt as it's a 93 so a bit of a cross over and the wiring has 'typical upto 91' then from 91, and don't assume that 'from 91' ACTUALLY applies to the 480 as well as the 440/460 !!!!!
Alan

480 ES 2litre x 2, C30 1.8ES, SS1

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brinkie
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Re: 480ES dash electrical problem

Post by brinkie » Tue Nov 20, 2018 11:44 am

There are four updates on the wiring, two minor and two major changes. The first couple of model years saw a lot of dealer updates, I even have an instrument cluster which uses undocumented connectors (clear/blue instead of yellow/blue), I have also seen cases of mating connectors which were modified to accept the actual production version. I think of the model years 1986-1988 as a very large mess, the biggest mess being the B18E-engine which changed from PTC to NTC sensors somewhere in 1987 and the introduction of the turbo engine in 1988. Starting with model year 1989 (major change to instrument clusters with green and grey connectors and several subtle changes) it became a bit stable. Half-way model year 1991 (say January 1991, VIN 567600) there was a HUGE update, with a complete redesign of the CEM. After that, there were updates with the introduction of the B20F-engine, the change from ATE MkII to MkIV ABS, and a completely rearranged fuse box.

From MY 1993 onwards the same wiring is used for the entire 400 series.
Well, mostly. Because the 480 has a CEM and popup headlights...
Robert.

Present cars: 1994 Volvo 480 GT 2.0i Vase Green, 2010 Volvo V70 2.0F Momentum Mystic Silver
Past: 1981 Talbot-Matra Murena 2.2 Rouge Mephisto, 1995 Volvo 480 GT 2.0i Paris Blue

andyb2000
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Re: 480ES dash electrical problem

Post by andyb2000 » Tue Nov 20, 2018 12:00 pm

Thanks folks, and sorry for not being a bit more concise on my info!
So the car is a 480ES 2.0L 1994. I think the confusion is I'd mixed a few of the terms up. It's the B20F engine, so has the Fenix 3B fuel injection if I'm correct? (What's the conclusive way of finding the engine edition?)

So yes, several elements tested alone confirm components seem to work:
Relays, coil and contact under load testing, all OK
Voltage to relay coil, 12v supplied for the prime time, so that looks fine
Pump when supplied with 12v (jumping relay switched contacts) runs fine also.

So, yes my thinking is the 3v is the voltage from the on/off cycle and my meter is reading it somewhere around 3v.
So going by the electrical wiring diagram (Yes, see wht you mean the Haynes isn't 100% spot on here, some of it is confusing to be sure it's the right edition. I'm working on the B20F engine when the page states its 440/470 from 1992, I'm reading that to also follow for my 480).

Image

So on the diagram there are several components joined to the D20 fuel pump. So when the pump relay (B12) is on it also supplies:
B15 = Oxygen sensor (Haynes says B18F/FT engines)
B11 = Idle speed regulating valve
B3 = Injectors (x4)
A12 = ECU

So any one of these components could be dumping to ground or causing the relay to drop voltage due to "short" conditions. Those I think are my next ports of call, probably disconnect each in turn and see if it changes the stability of voltage supplying the relay.
(I'm going to find how to get the volvo green manual, as sounds like that might piece more of the puzzle together)

Thanks again everyone, will see what I can find.
Thanks for all your help! - Andy
Volvo480 ES 2.0 petrol - 1994 (UK RHD L-reg)

andyb2000
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Re: 480ES dash electrical problem

Post by andyb2000 » Tue Nov 20, 2018 12:46 pm

VIN lookup to the rescue:

Volvo 480
3 point seat belts + airbag + seat belt pretensioners
B20F
5-speed manual gearbox
1994
NedCar, Born (Netherlands)
Perhaps car 647 constructed in 1994
Thanks for all your help! - Andy
Volvo480 ES 2.0 petrol - 1994 (UK RHD L-reg)

Alan 480
480 Is my middle name
Posts: 1059
Joined: Sun Aug 28, 2011 9:03 am
Location: Aberdeen

Re: 480ES dash electrical problem

Post by Alan 480 » Tue Nov 20, 2018 12:55 pm

brinkie wrote:
Tue Nov 20, 2018 11:44 am
From MY 1993 onwards the same wiring is used for the entire 400 series.
Well, mostly. Because the 480 has a CEM and popup headlights...
:D
Alan

480 ES 2litre x 2, C30 1.8ES, SS1

andyb2000
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Re: 480ES dash electrical problem

Post by andyb2000 » Mon Dec 17, 2018 3:30 pm

So, it's been slow progress (too cold outside! I really need a lockup to put my precious 480 in!), but I've done a little more.
Disconnecting the O2 sensor at the electrical connector behind the battery (traced wires to O2 sensor in downpipe) and this seems to cause the relay to chatter less, but not completely OK, which makes me go back to a bad earth/ground since it improves when I remove "paths".
I then removed crank and idle sensor connectors too, again improvement but not totally clear.

The problem I've got is I can't locate the injection ECU, doesn't look like it's in the driver-side footwell, where else would it be? I think this is the next port of call to check for problems.
Thanks for all your help! - Andy
Volvo480 ES 2.0 petrol - 1994 (UK RHD L-reg)

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jamescarruthers
480 Is my middle name
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Re: 480ES dash electrical problem

Post by jamescarruthers » Mon Dec 17, 2018 3:47 pm

It is in there! Look at the panel that contains the bonnet release on the passenger side (for a RHD UK car)... now find the same panel on the driver's side!‎ It's behind that. 
1987 Volvo 480 ES, 507274, 217 - Red (Ness)
2001 Volvo C70 2.4T convertible (Olivolvo)
2008 Mini Cooper convertible (Mau)

Previous 480's:
J123 CFU -- ES
J449 MNL -- ES auto
D864 CPV -- ES
L691 JFC -- Turbo
F70 MNR -- ES
H858 FGV -- Turbo auto
E981 KHM -- ES (509849)

dcwalker
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Re: 480ES dash electrical problem

Post by dcwalker » Mon Dec 17, 2018 6:35 pm

Yep - as James says, it is definitely there! It's basically in the same position as the CEM you have already removed previously, but on the driver's side. Remove that equivalent panel to the one on the passenger side that has the bonnet release and you should immediately see the multiplug connector...

David
Current: 1994 480 GT, 1995 480 Celebration 467/480 (plus 2004 C70 Collection)
Previous: Celebration 346 (sold to Alan480), Celebration 269 (scrapped abandoned project), Celebration 73, 1992 ES, 1988 ES - and numerous other non-480 Volvos!

andyb2000
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Re: 480ES dash electrical problem

Post by andyb2000 » Mon Dec 17, 2018 8:21 pm

Aha! Persistence (And good advice! Thank you fellas) has paid off, there it is!

Image

Image

And inside it, looks pretty decent, no corrosion or water damage that I was potentially expecting.

Next will be to trace the supply and ground wires on the connector and ensure there is good ground, etc.
Thanks for all your help! - Andy
Volvo480 ES 2.0 petrol - 1994 (UK RHD L-reg)

andyb2000
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Posts: 40
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Re: 480ES dash electrical problem

Post by andyb2000 » Mon Dec 24, 2018 9:18 am

So, I've now got the dash bulbs installed and my info centre lights up, so dashboard is back in one piece now.
After plugging ECU back in (dash side) I'm getting the same problem, flickering relays so wasn't just a bad connector there. I'm going to trace the wiring loom now and see if there are any dodgy wires, possibly also just drag a ground wire direct from battery round to ecu/relay and test a solid ground as that's still my thinking.
This one is frustrating me though as so close but still can't solve!
Thanks for all your help! - Andy
Volvo480 ES 2.0 petrol - 1994 (UK RHD L-reg)

andyb2000
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Re: 480ES dash electrical problem

Post by andyb2000 » Sun Jan 06, 2019 5:32 pm

So now I think I've unfortunately discovered the problem.

B12 is the fuel relay pump (On my 480es it's the white/clear relay connector), testing for voltage using my multimeter on pins 86 and 85, it's constantly powered, regardless of ignition switch position! That's not right. So the switching is done via the ECU which grounds pin 85 to pull the relay.
If I connect the relay back in and test voltage again, voltage is around 0.8v so it's like a quiescent voltage and when the load of the relay is added it's not enough to hold voltage up. When ignition is on the voltage jumps up and down constantly causing the relay to energise on and off.

B2 is the control relay which again is controlled by ground switched through the ECU (ECU-B20F). Testing this and the behaviour is exactly the same. It also clicks as the relay energises on and off.

So both relays appear to be getting strange "leak" voltage constantly to their coils and when ignition is on the ECU is pulsing the ground erratically.

My conclusion? Knackered ECU-B20F? To me it's not operating correctly, leaking voltage and not maintaining enough current to hold the relay open (Or indeed the control signal itself is jumping on/off).
Is there a way to determine the state of the ECU in another way? Anything else that's dependant on the ECU that would indicate if it was working at all, or is it a job of trying to buy a replacement and hope for the best?
Thanks for all your help! - Andy
Volvo480 ES 2.0 petrol - 1994 (UK RHD L-reg)

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