2004 V70R Central Electronic Module CEM THERMAL CONNECTION ISSUES Topic is solved

[SixerFixer]

Hi Everyone,

Cross-posting this with the SwedeSpeed forums for as many opinions as possible! I'm having some very sudden major problems with my '04 V70R (5-speed automatic), resulting in it not being drivable. A bit about the car first: it's a higher mileage car with 480,000 km on the odometer (roughly 300,000 miles), and recent relevant work within the past year includes a new alternator and battery, iPd TCV, replacement alarm module, and a servotronic power steering relay. The car is extremely well maintained, and has never given me any problems like this in the past.

Yesterday as I was driving to the airport, the dashboard suddenly lit up like a christmas tree (check engine light, abs light, warning triangle, etc), all the instrument gauges went to 0, the trip odometer read - - -, the gear indicator read -, and the transmission locked itself in 3rd gear. The warning messages "BRAKE FAILURE - STOP SAFELY" and "ENGINE SYSTEM SERVICE REQUIRED" pop up on the cluster as well. After limping the car home, I found that if it was left to idle for a little bit, the motor would sputter out, and it would refuse to start again for a little while. Fun.

Anyways, I left the car to cool down for several hours before running a scan, and found that it started up and idled as normally, albeit with all the dashboard lights and warning messages on. A scan yielded the following codes:

ECM-E000 Control module communication - Faulty communication
ECM-E003 Configuration fault - Faulty configuration
SUM-0334 CAN-signal, BCM control unit faulty signal
SUM-E000 Control module communication Signal missing
SUM-E003 Control module communication Configuration fault
BCM-0058 Power supply Voltage too high
BCM-0139 Pre-pressure valve power brake booster Signal outside its permitted range
CEM-1A5E Communication with SAS control module Signal missing
CEM-1A64 Communication with AOC control module Signal missing
CEM-1A65 Communication with SUM control module Signal missing
SAS-E003 Configuration fault Faulty configuration
SUM-0201 Control module Signal too low
SUM-0324 CAN-signal, BCM control unit Signal missing
SUM-0337 CAN-signal, SAS control unit Faulty signal

Phew. What a list. From my understanding, a majority of these codes were likely caused due to a cascade of error triggering caused by a single source.

Anyways, I cleared everything while in the driveway, and ran a SUM calibration (among other calibrations and tests), as well as tested all the valves associated with the BCM to check for problems, and everything seemed fine, and the problem had gone away. Took the car up to operating temperature, drove it around the block a few times (I'm sure my neighbours were thrilled to hear my iPd exhaust humming around the block after dark), and the problem did not manifest again. I read a bit and determined that this might just be a one-time occurrence, and that simply clearing all codes may have resolve the issue. Unfortunately this was not the case. I made the foolish mistake of trusting the car this morning, a mistake I have made many times in the past, and the problem decided to rear its ugly head again on my way to work. I unfortunately had left my diagnostic equipment at home, and had to abandon the vehicle on a side street so I could get to work.

Now, I've done quite a bit of reading as to what may be causing the problem, and only seem to find answers from the S60/V70/XC70/S80 crowd, so hopefully their findings might be applicable to my scenario. With the list of codes I provided, people tend to point their fingers at a faulty BCM, brake booster, ignition switch, alternator, battery, or battery cables. In one instance, I read that it may have been due to ECU/TCM overheating due to a faulty fan that cools the box in which the control units are housed. I'm leaning away from the alternator/battery, as both had been recently replaced.

The BCM could be a possible culprit, but from what I've read, a faulty BCM would typically trigger multiple specific codes, and not just a single one for the pre-pressure valve on the power brake booster. New BCMs are incredibly expensive, but can be rebuilt by a gentleman named Victor for around $150, so that seems somewhat reasonable, if it is indeed the problem. My hunch is leaning towards the pre-pressure valve in the brake booster itself, due to it being the only specific fault found in the scan; it may have triggered a fault, which lead to a BCM, fault, which cascaded down to a multiple system failure in the vehicle. Unfortunately, the repair sounds pretty labour intensive, and the part itself is quite expensive.

So I must ask the question: does anyone have any idea what might be truly wrong? I will run another scan this evening and see if the same codes are present from the second manifestation of the problem. The people on SwedeSpeed believe that it may indeed be a battery issue, but both the alternator and battery were replaced 5 months ago, and diagnostics software read a charging voltage of 13.5V at idle, and the battery slowly drained from 11.9 to 11.5V while carrying out diagnostics etc, due to the headlights and accessory lights being on at the time.

Also, thanks for being willing to read through this essay of a post

[grntrdbx]

Did you ever figure out what the issue was? I am having the same issue on my '04' V70R. Any help would be appreciated. It is currently dead in the driveway after fiddling with it for 3 days. I really don't want to drag it to the dealership unless it's necessary. Thanks.

[draser]

Did you scan the codes?

[bugeye]

The post from SixerFixer sounds exactly like our '04XC70. I first changed the battery. No joy. We had the codes read resulting in a long list. Advice from independent Volvo shop was to identify which code came first. But, they all came at once. From reading the forums, I took a leap of faith and sent the CEM to XeMODeX for rebuilding/reprogramming. Plug and play and quick turn around. CEM was reinstalled and XC has had no issues in the past year. I have read the '04 and earlier CEM overheat. The '05 newer and rebuilt CEM has a heat sink.

[rubbersidedown]

Best bet is to swap to a known working BCM (ABS module). If you have DSTC you may not get an exact match of sw configuration (not sure about std or STC type BCM), but all error codes and symptoms may/should go away (except sw config, but no biggie). A faulty BCM can throw all sorts of error codes incl immobiliser, transmission, ABS sensors, communication errors etc. Rough shifting, engine stops etc happens too. That is what I did and the car purrs like a cat again.

[packetfire]

I had this same issue with a 2004 v70 (non-turbo, non-R). The symptoms were:

1) Transmission seemed to slip for a moment, higher revs (around 2800rpm instead of 2000rpm) than one would expect for the throttle applied.
2) "Brake Failure - Stop Safely", but the brakes seemed to work fine.
3) Dead Tachometer
4) Dead Fuel Gauge
5) Dead Speedometer
6) Working Engine Water Temp Gauge (go figure!)

All this lead me to think that I had a DIM issue, as the car was running smoothly, and I simply had instrument failures.
I pulled off into a parking lot, and tried to pull codes with VIDA (VIDA was in the toolkit, and I had a laptop with me). No dice, to coin a bad pun. VIDA could not read anything, but the DICE unit passed diags fine.

Restarted car, and got a series of messages from the DIM - "Brake Failure", as above, also "Transmission Service Required" and "Engine Service Required". No way a car with zero codes at last diagnostics pass was suddenly having failures from every major subsystem.

So, it had to be the CEM itself, as the VIDA talks to the CEM, which then talks to everything else. Did a headstand, pulled out the CEM assembly, labeled the relays and shunts with tape and magic marker, and removed them so I could pull the circuit board. Removed the RFI shield cover from over the CPU and the flash chip, and reassembled all. Of course the time to do all this, 20 mins or so, allowed the CEM to cool down, as I pulled the negative battery cable before pulling the CEM. This was the first morning since I acquired the car where I had the heat on, as it was a chilly cold morning.

No further problem, but I have ordered heat sinks for both the CEM chips (processor and flash memory, the two largest chips within the RFI shield), and for the REM chips also.

I am assuming that the heat sinks will do the job, but if it happens again with the heat sinks, I'll get it reworked by one of the rebuilders, but this was an event that was solved with only a torx-20 bit, masking tape, and a sharpie, plus the usual sockets required to get at the battery, and pull off the negative lead. Given the under $20 cost of heat sinks, I'd say that this is a good thing to do for any pre-2005 v70, before it causes problems.

[SPAREROOM1996]

Hi Everyone,

Cross-posting this with the SwedeSpeed forums for as many opinions as possible! I'm having some very sudden major problems with my '04 V70R (5-speed automatic), resulting in it not being drivable. A bit about the car first: it's a higher mileage car with 480,000 km on the odometer (roughly 300,000 miles), and recent relevant work within the past year includes a new alternator and battery, iPd TCV, replacement alarm module, and a servotronic power steering relay. The car is extremely well maintained, and has never given me any problems like this in the past.

Yesterday as I was driving to the airport, the dashboard suddenly lit up like a christmas tree (check engine light, abs light, warning triangle, etc), all the instrument gauges went to 0, the trip odometer read - - -, the gear indicator read -, and the transmission locked itself in 3rd gear. The warning messages "BRAKE FAILURE - STOP SAFELY" and "ENGINE SYSTEM SERVICE REQUIRED" pop up on the cluster as well. After limping the car home, I found that if it was left to idle for a little bit, the motor would sputter out, and it would refuse to start again for a little while. Fun.

Anyways, I left the car to cool down for several hours before running a scan, and found that it started up and idled as normally, albeit with all the dashboard lights and warning messages on. A scan yielded the following codes:

ECM-E000 Control module communication - Faulty communication
ECM-E003 Configuration fault - Faulty configuration
SUM-0334 CAN-signal, BCM control unit faulty signal
SUM-E000 Control module communication Signal missing
SUM-E003 Control module communication Configuration fault
BCM-0058 Power supply Voltage too high
BCM-0139 Pre-pressure valve power brake booster Signal outside its permitted range
CEM-1A5E Communication with SAS control module Signal missing
CEM-1A64 Communication with AOC control module Signal missing
CEM-1A65 Communication with SUM control module Signal missing
SAS-E003 Configuration fault Faulty configuration
SUM-0201 Control module Signal too low
SUM-0324 CAN-signal, BCM control unit Signal missing
SUM-0337 CAN-signal, SAS control unit Faulty signal

Phew. What a list. From my understanding, a majority of these codes were likely caused due to a cascade of error triggering caused by a single source.

Anyways, I cleared everything while in the driveway, and ran a SUM calibration (among other calibrations and tests), as well as tested all the valves associated with the BCM to check for problems, and everything seemed fine, and the problem had gone away. Took the car up to operating temperature, drove it around the block a few times (I'm sure my neighbours were thrilled to hear my iPd exhaust humming around the block after dark), and the problem did not manifest again. I read a bit and determined that this might just be a one-time occurrence, and that simply clearing all codes may have resolve the issue. Unfortunately this was not the case. I made the foolish mistake of trusting the car this morning, a mistake I have made many times in the past, and the problem decided to rear its ugly head again on my way to work. I unfortunately had left my diagnostic equipment at home, and had to abandon the vehicle on a side street so I could get to work.

Now, I've done quite a bit of reading as to what may be causing the problem, and only seem to find answers from the S60/V70/XC70/S80 crowd, so hopefully their findings might be applicable to my scenario. With the list of codes I provided, people tend to point their fingers at a faulty BCM, brake booster, ignition switch, alternator, battery, or battery cables. In one instance, I read that it may have been due to ECU/TCM overheating due to a faulty fan that cools the box in which the control units are housed. I'm leaning away from the alternator/battery, as both had been recently replaced.

The BCM could be a possible culprit, but from what I've read, a faulty BCM would typically trigger multiple specific codes, and not just a single one for the pre-pressure valve on the power brake booster. New BCMs are incredibly expensive, but can be rebuilt by a gentleman named Victor for around $150, so that seems somewhat reasonable, if it is indeed the problem. My hunch is leaning towards the pre-pressure valve in the brake booster itself, due to it being the only specific fault found in the scan; it may have triggered a fault, which lead to a BCM, fault, which cascaded down to a multiple system failure in the vehicle. Unfortunately, the repair sounds pretty labour intensive, and the part itself is quite expensive.

So I must ask the question: does anyone have any idea what might be truly wrong? I will run another scan this evening and see if the same codes are present from the second manifestation of the problem. The people on SwedeSpeed believe that it may indeed be a battery issue, but both the alternator and battery were replaced 5 months ago, and diagnostics software read a charging voltage of 13.5V at idle, and the battery slowly drained from 11.9 to 11.5V while carrying out diagnostics etc, due to the headlights and accessory lights being on at the time.

Also, thanks for being willing to read through this essay of a post

HI EVERYONE.
LAST NIGHT I HAD THE VERY SAME SYMPTOMS ON MY 2008 S40 2.0D R-DESIGN, SAME SYMPTOMS AND WOULD NOT START
TURNED OUT THAT BECAUSE WE HAVE A LOT OF SPEED HUMPS IN THIS AREA, THE CONNECTORS ON THE BCM/FUSE BOX HAD WORKED LOOSE. SO FRACTIONALLY THAT IT WAS HARDLY VISIBLE. SO, I DROPPED THE FUSE BOX, TOOK THE THREE MULTIPLUGS OUT AND REINSTALLED THEM. I REPLACED THE FUSEBOX/BCM MAKING SURE IT WAS IN CORRECT AND CORRECTLY TIGHTENED AND HEY PRESTO..THE PROBLEM HAS GONE
DEFINITELY WORTH A TRY BEFORE GOING TO VOLVO TO GET STUNG

[erikv11]

Great to know, thanks SPAREROOM!

[Kara503]

I'd like to piggyback with my recent experience-

2004 S60 2.5T. Going into limp mode intermittently and displaying 'Brake failure- Stop safely'. CELs set-
p0863 -TCM fault
U0002- ‘High speed CANBUS performance’
P0600- Serial communication malfunction

I unplugged the ECU and TCU (Requires a special tool, but I just used a screwdriver and was extra careful), cleaned the contacts of both really well with contact cleaner, let them dry, and put it all back together. The issue hasn't reappeared in 4 months and the car is my daily driver.

Very similarly, an s40 I recently bought was also going into limp mode with a message along the lines of 'Transmission service urgent'. Turns out the electronic gas pedal module can have an intermittent connection sometimes. Unplug the pedal module at the pedal and where it connects to the CEM, clean the contacts, rehook, and the issue hasn't come back up now after 2000 miles!

Crazy how much something like the equivalent of 'Have you tried turning it off and then back on again' can help!