04 XC70 Transmission Service Required - where to start?

[precopster]

I use a flat blade to pry the ears away from the CEM case. Once one side is released you keep force on it until you get to the other ear. Needless to say you need a good work light so you can see the release tabs.

Getting them back in is a cinch. Just insert it into the rounded holes until you hear the ears both click back in when it's back at the correct angle.

Don't forget to clean the transmission connectors close to the air cleaner. They are attached to a metal bracket via a sliding assembly. Release the tab and slide them all off.

[mikeamondo]

Thanks... can you give me a more detailed descrip of the Transmission connectors at the Air box? Sorry to be dense, but I'm just not spotting them. I found a single connector directly in front of the air cleaner box, connected with a wire release, which I cleaned. And then directly in front of the box is a plastic card like riser with several electrical connectors mounted to it, but I could not find where it connected to a metal bracket.... was this what you were talking about? And where is the tab to release it if so? I'd really like to get these cleaned before I test the car out today....
Thanks!
Mike

[oragex]

Just did the first of 3 drain and refills.... the oil was Filthy, with a capital F. Not anything like that lovely lavender color that showed up on the dipstick, which I getting better at pulling without burning my hands.... Also, I drained 4.25 liters out, so I only put 3.3 back in and took her for a 20 mile drive.

I think the box should drain 3.5 l so you are pretty close to it by now. For the CEM, have you checked the Youtube videos about how to remove it?

[precopster]

Thanks... can you give me a more detailed description of the Transmission connectors at the Air box? Sorry to be dense, but I'm just not spotting them. I found a single connector directly in front of the air cleaner box, connected with a wire release, which I cleaned. And then directly in front of the box is a plastic card like riser with several electrical connectors mounted to it, but I could not find where it connected to a metal bracket.... was this what you were talking about? And where is the tab to release it if so? I'd really like to get these cleaned before I test the car out today....
Thanks!
Mike

Yours is the earlier style CEM as in the video at the top. The 10mm bolt on the CEM releases the connector after much prying upward. You don't need to remove the relays just to clean the connector.

Yes the riser card is attached to a metal bracket behind it. There is a single plastic release to bend out of the way to slide the riser right up however you can release all 3 connectors individually while they are still attached to the metal riser behind it. Sounds like you need a work light there!!

[mikeamondo]

Thanks! I wish I had an excuse like not having a light, but I've got a nice one.... Just couldn't spot the release... at least I now know I was looking in the right area. I thought about taking off the connectors where they sat.... I'll get those cleaned up tonight.

So far, I did the 12 mile drive last night at another 12-15 into the office this morning, mostly downhill, with no problems. Today, I'll take her for an extended drive in the heat of the day and run up Cheat Mountain on I-68... that should give ample opportunity for the error to return. I'll clean those other connectors and the CEM regardless.

@oragex - that first vid is the exact one I watched... but you can see he uses no tools, no flat blade, no prying. He just reaches up with his right hand while he says "push on the bracket" and then he pulls ever so gently on the bottom of the CEM and seems to slide right out. But the video (due to the tight spaces) does show him pushing or pulling up at the top end. Since mine didn't pop easy like his did, it was of little use. I'm think about taking a stab at making a video of my own if I figure this out.....

[precopster]

I've released CEMs about 9 or 10 times and always used a flatblade to pry the metal bracket away from the CEM on both sides though this was always done on S60s, V70s and XC70s.

The later CEM is harder to remove. Wipers and wiper cowling as well as wiper motor need to come out.

[oragex]

It's true that is very hard to spot. Volvo is the king of hard to understand and to disconnect brackets. Yesterday I removed the fuse box under the hood, it has two brackets each sliding off in a different direction.

Notice how the bracket has a 'hook' on each side http://xemodex.com/us/pdf/xemodex-cem-removal-99-04.pdf
A mirror may also help

[mikeamondo]

Ok... so a good day with some good updates, but a frustrating evening on a couple counts. First... the car. Drove a total of 70 ish miles today without an incident. As a point of reference, the last time we drove prior to cleaning the ECM and TCM, she had issues starting at 20 minutes or so and multiple occurrences in an hour of driving. I drove her up a 5 percent grade about 4 miles at 70 mph and up and over two other mountains.... no issues at all. Not enough to say 'fixed' but a good sign.

At home this evening, I figured out how to remove the CEM. No tools, no blade... just like the guy on the video. The side of the white bracket on the back side (fender side) of the CEM is long.. almost as long as the CEM it self. You can't really see it.. need to feel for it. Run you fingers up the backside about an inch or so from the bottom corner and you'll run into the end of the bracket. Push out on this and the CEM just releases and pulls forward. The length of that back tab acts as a lever and gives enough power to bend the metal and release the CEM. At least it did on mine.

Now the frustrating part.... I removed the 10mm bolt on the connector to the CEM but could not get the connector out of the CEM to clean it. Pulled on it until I heard a cracking sound and then decided, given the days' driving, it might not even be necessary, so I put it back. Some details on how to pry it out would be appreciated.... do you pry with a tool of some kind, where can you pry, etc..... If the car acts up again, I'll start there.

On the plugs at the air cleaner, I'm 2 for 4. I did find the release but it only help marginally. Two the plugs I managed to get apart, but two other I pulled on, pushing on the tabs, for nearly an hour, until I thought my fingers might bleed and gave up. The two I did open up seemed to have been cleaned and greased at some point... there was still dielectric grease in the pin holes.

So.... over the next couple days will be driving the car a good bit, culminating with a 2 hour drive to the Pittsburgh Airport on Friday. That should give a solid indication that it's fixed. I'll post an update after that..... Thanks for all the continued help! Could not figure anything out without you good folks!
Mike

[mikeamondo]

UPDATE -- Thought I had it fixed! Drove 200 plus miles, including a trip to the PIT airport and a return trip a couple days later, about 100 miles each way, total of maybe 400+ trouble free miles. Drove through an absolute torrential downpour most of the way back from the airport, no issues. The next day, I had a single event happen with a couple differences. AC went warm, speedo, temp, tach quit, Brake failure warning on dash, but no transmission warning. It did not fix itself until I stopped and a restart made it all go away.
Since that day, we've gone another 150 - 200 miles with no more issues, all a mixture of city and some interstate driving, 20 miles trips.

The Codes: This time I got ECM for the brake pedal and Steering wheel mod., BCM for faulty comm, stop lamp switch faulty sig & outside permitted range, and CEM E000 faulty comm with control module..

NOTE... those are all ECM or BCM related... not TCM. So.... is it possible I made headway and fixed the TCM, but didn't get the ECM clean enough? There was a small difference in how I cleaned them and greased them. The TCM I put the grease right onto the pins, brushed it in with the toothbrush and then carefully dug out the excess for fear it would cause an electrical connection between the pins. On ECM I put the grease onto the holes in the receiver, not the pins, and then squished it down in a bit with my finger and wiped off the excess. So maybe I should regrease everything on the ECM.... ?

So here are a couple questions...
1) After cleaning with a toothbrush and contact cleaner, what's the proper method for applying dielectric grease on the ECM and TCM?
2) Can someone better explain the method to "pry off" the connector on the CEM? I pulled until I heard a nasty cracking sound and then quit, but I'd like to make sure that connector is clean.
3) Does the BCM showing up the codes mean anything more than the already assumed communication issues?

Thanks!
Mike

[FrankAZ]

In the spirit of giving back to this community from which I have learned a lot I shall describe my "Transmission Service Required" experience in the hope that it may save someone some frustration. The short answer is that all was solved when I replaced the battery.


About 10 days ago my wife came home and reported that her 2004 Volvo V70 2.5T FWD had flashed a Brake Failure message and some others too, and almost immediately thereafter had wriggled while driving. Upon my insensitive interrogation I think she was describing some random single wheel braking and perhaps lockups. We swapped cars in the interim so that I could better experience the pleasure should it reoccur. Married readers may surmise the sub-plot.

Over the next few days I saw some infrequent ABS failure messages and some brake failure messages but no handling difficulties and indeed except for the messages, and both the ABS and Check Engine lights illuminating the car seemed to drive well. If I parked and re-started then the ABS light and message cleared, and my basic code scanner was reporting a U0002 code, a High Speed CAN Bus Performance error. I could clear that code with my tool.

I suspected the ABS module connectors or friction joints as described in this (viewtopic.php?f=1&t=12651) and other threads. I was all worked up to remove/repair/replace over the Thanksgiving weekend when I could organize a cool engine.

But, on Thanksgiving morning the car threw U0073 (Control Module Communication Bus A Off) and P0571 (Cruise Control/Brake Switch A Circuit Malfunction) codes, which I cleared after noting them. But, I had to switch off to clear the codes and when I restarted I received the ABS failure warning again and after driving a few yards received the Transmission Service Required message, noticed the dash gauges were dead, and that the gear indicator was '-'. After stopping again I was unable to start the car, only hearing a loud click from behind the dash (not the starter solenoid) followed by a jittering click-click-click- relay rattle.

I decided to replace the battery - yay for my good fortune of needing a battery on Black Friday when there were discounts available! After replacing with a Bosch B-AGM battery ($200 reduced to $100 after discount and rebate) all was well again with the Volvo EXCEPT that Transmission Service Required message and yellow hazard triangle symbol which my OBD-II tool could not reach since it came from the TCM. The car behaved impeccably otherwise and threw no more codes over the rest of the weekend and I ignored the transmission error.

This morning I took the car to a local transmission shop where the TCM was read. They tell me the only code was a communication error code which they cleared for free. It's good to know that the transmission is still good, or at least error-free, after 156000 miles too.

So... a failing battery caused a bunch of CAN bus errors that eventually were stored in the TCM and required a more professional (or DICE-VIDA) tool to clear. The battery-induced bus errors exhibited as Brake Failure, ABS Module errors, ECM errors, the Transmission Service Required message, CEL and ABS lights to illuminate, dash gauges dying, and even random wheel lock-ups while driving. All while the battery showed no difficulty in starting the car except that last time in which it was unable to crank the engine for the first and only time.

Takeaway: if your battery is old and you see combinations of the earlier errors all related to the high speed CAN bus first suspect the battery and maybe even replace it proactively so that you fix the issue before a bus error causes the TCM flag to be set and a more inconvenient or expensive reset. For an older battery it would certainly be more cost- and time- effective to replace it first before going elbow-deep into the engine bay and one or more of the computers.

Frank