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Light warning ⚠ issue Topic is solved

Help, Advice, Owners' Discussion and DIY Tutorials on Volvo's stylish, distinctive P2 platform cars sold as model years 2001-2007 (North American market year designations).

2001 - 2007 V70
2001 - 2004 V70 XC (Cross Country)
2004 - 2007 XC70 (Cross Country)
2001 - 2009 S60
2003 - 2007 S60 R
2004 - 2007 V70 R

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ashleyg82v702001
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Re: Light warning ⚠ issue

Post by ashleyg82v702001 »

I'll check them all again and change them with new just to be sure... I'm absolutely positive ALL BULBS are working and have correct bulbs 2x (4w/21w possition / fog) duel filaments
2x t10 in number plate
2x (ba15 5w possition) single filaments
And all the led light in the high level brake

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abscate
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Post by abscate »

Ashley...my 2005 has had a two year interval problem in the REM. The fuses oxidise and I get failure of lights in various circuits. Intake the fuses out and clean them with a sharp, stiff blade and I’m good for another 24 months.

The REM is dry and the event happens regardless of rain or humidity

I failed my last MOT due to reverse lights being out, but my shop had a note in my log so the cleaned and replaced it for me.
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1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 XC90-in-Red
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ashleyg82v702001
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Post by ashleyg82v702001 »

Lucy has had the backend gutted this morning... No broken wires. However I unplug the harness on the rem side back door by the earth points and all lights go out no further messages. So now I'm convinced it is a problem in the rear of the car beyond the back seats..
DSC_1770.JPG
I don't even care if the warning system stops working is there anything I can do with the shunts to just kill the error reporting?
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DSC_1771.JPG

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firstv70volvo
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Post by firstv70volvo »

ashleyg82v702001 wrote: 10 Dec 2020, 05:43 Lucy has had the backend gutted this morning... No broken wires. However I unplug the harness on the rem side back door by the earth points and all lights go out no further messages. So now I'm convinced it is a problem in the rear of the car beyond the back seats..
DSC_1770.JPG

I don't even care if the warning system stops working is there anything I can do with the shunts to just kill the error reporting?
All the bulb out warnings you are seeing are related to each of the shunts in the REM. The REM monitors the voltage drop across low resistance shunts and if the voltage drop is less that expected you'll get the bulb out warning. If a bulb is out there will be less current and a lower voltage drop across the shunt resistance. I'm wondering now if there's just something wrong with the REM itself. If the REM is not measuring the voltages correctly (or some other problem) then you'll get the bulb out warnings. There are 5 shunts, 4 to monitor the lights and 1 for the 12V socket in the rear compartment. I think it would be difficult to do something with the shunts to avoid the errors especially if the REM is not measuring the voltage correctly. The middle part of the REM is the electronics and the replacement part new is close to $400 and I'm not sure if programming is needed for the REM, if not then a salvage part may work.
Last edited by firstv70volvo on 10 Dec 2020, 10:12, edited 1 time in total.

ashleyg82v702001
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Post by ashleyg82v702001 »

OK, so are these interchangeable without programming if I match the part number (or do I need one with the exact same accessories from a different car? ) because I cannot afford to put another £500+ into the car like I did for the etm.

Can someone post a live monitor of what is seen from the bulb failure part on their diagnostic reader possibly?
I get a flat line on all lights of 0 . What should I be seeing?

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firstv70volvo
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Post by firstv70volvo »

ashleyg82v702001 wrote: 10 Dec 2020, 10:09 OK, so are these interchangeable without programming if I match the part number (or do I need one with the exact same accessories from a different car? ) because I cannot afford to put another £500+ into the car like I did for the etm.

Can someone post a live monitor of what is seen from the bulb failure part on their diagnostic reader possibly?
I get a flat line on all lights of 0 . What should I be seeing?
I don't know how interchangeable the REMs and if programming can be avoided. Hopefully someone else can provide this information, I do know the REM design is definitely different from 2005-on. One thing you could still do is disconnect the battery and pull out all the relays, shunts and fuses out of the REM and check for any overheating or corrosion on the leads and sockets.

ashleyg82v702001
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Post by ashleyg82v702001 »

This now confused me a little, looking through mathews and I see comments of the lower brake lights are controlled by the 'rem' but the high level is controlled by the 'cem' and the reader I have says its a brake light issue involving the 3rd light... 😭 .. The cem is under the steering wheel, yes?
I'm going to pull that tomorrow now

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firstv70volvo
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Post by firstv70volvo »

ashleyg82v702001 wrote: 10 Dec 2020, 11:06 This now confused me a little, looking through mathews and I see comments of the lower brake lights are controlled by the 'rem' but the high level is controlled by the 'cem' and the reader I have says its a brake light issue involving the 3rd light... 😭 .. The cem is under the steering wheel, yes?
I'm going to pull that tomorrow now
I don't think you need to pull the CEM, it does send the brake signal back to the REM and since your brake lights are working this signal from the CEM is working as it should. The 3rd brake light is also controlled by the same signal but the routing through the REM is different, the problem for this light is with the REM or possibly the LED light strip itself. The left and right brake lights are powered on through a relay and the 3rd light LED strep is a line directly out of the REM itself. All the problems you're having seem to be only with the REM.

ashleyg82v702001
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Post by ashleyg82v702001 »

OK thankyou,
Hopefully saves me wasting a morning tomorrow then.
Maybe I just have to live with it until more goes wrong rather than spend out for what is essentially a novelty feature...

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firstv70volvo
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Post by firstv70volvo »

ashleyg82v702001 wrote: 10 Dec 2020, 11:06 This now confused me a little, looking through mathews and I see comments of the lower brake lights are controlled by the 'rem' but the high level is controlled by the 'cem' and the reader I have says its a brake light issue involving the 3rd light... 😭 .. The cem is under the steering wheel, yes?
I'm going to pull that tomorrow now
Just for reference, I had a problem with the 3rd brake light LED strip and an error in Vida for the signal going to this light. It turned out to be a connector that plugs into the LED strip circuit board. I cleaned the two pins that plug into the socket and all was well. The problem was the 3rd light wasn't working and if I tapped on the back of the tailgate near the light it would come on. It was an intermittent problem but mostly it didn't work. The LED light assembly can be taken apart to get to the two pin connector, it just snaps together. You have to pull off the inner panel of the tail gate, which is 4 torx screws and pry out the handle piece then remove this panel and pry out the top panel to get to the upper brake light.
3rd brake light connector unplugged.jpg
3rd brake light connector.jpg

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