ETM Cleaning or Disassembly

[prwood]

I’ve got an ‘01 V70 with the Magneti Marelli ETM. I know I’ll soon have to replace it, but for now I’ve got it removed so I can give it a good cleaning and hopefully delay the inevitable a bit longer. :-/

Would there be any benefit to disassembling the ETM and cleaning out the internals, or should I just stick to cleaning the external surfaces?

[abscate]

I took an original operatingMM off a 200,000 mile 1999 V70T5M ,so they can last quite a while.

[Georgeandkira]

FYI:
If I remember correctly (and I tend to) there's an ECM download which changes the location on the "wear zone" of the mylar wiper in those early MM ETMs.

I do not have the p/n of the download.

[abscate]

Prw....take a look in the ETM room for some of the internal shots of the throttle body to get feel for complexity.

I'm a risk taker but I'll describe recollection of this as 8/10 complex, with 10 being design hell and 0 being intuitive

Clean off al the black tar with a hexanes based cleaner and soft brush, rinse any particles away.

[prwood]

Thanks all. I am fairly certain that the car had the ETM software upgrade before I purchased it - I obtained service records from the original selling dealer and saw these notes as items F and G on the 90,000 mile service:

F 99VOZ155 . VEHICLE IS DUE FOR SERVICE CAMPAIGN 155
864 964 F W 0.30 99VOZ155 RECALL 155 0.00
0.00

G 51VOZZ1 WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW VEHICLE WENT TO "SLEEP" WHILE PERFORMING RECALL 155.
864 964 G W 1.10 51VOZZ1 BODY ELECTRICAL 0.00

Recall 155 is the ETM upgrade. I'm not sure what the second note means, but I'm assuming that they were able to "wake" the vehicle to finish installing the upgrade.

I have followed the diagnostic flowchart from Xemodex:

https://xemodex.com/us/pdf/ETM%20Flow%2 ... -final.pdf

"Any codes related to MAF? -> No -> Any misfire codes? -> No -> Is the following code combination stored? (P-1017, P-1019, P-1020, P-1021, P-1043 and P-1052.) -> No -> Are there any ETM TPS sensor codes stored? -> Yes (P0121) -> Replace the ETM"

I just found this thread by precopster: viewtopic.php?f=12&t=52151

In my past cleanings of the ETM, I've made both of the mistakes he warns against - I opened the throttle plate to the vertical position while cleaning, and I use water-based spray on degreaser (Purple Power) to do the cleaning. So I'm sure that hasn't helped.

I also just found this poor guy who broke some wires when disassembling his ETM, and incidentally didn't get any replies to his post... from two years ago...

viewtopic.php?f=12&t=68913&p=360512

I'd like to think I could avoid that mistake if I was careful, but I dunno...

[mrbrian200]

Not every single ETM goes bad. Just a fair number of them. I personally know somebody who owns an '01 V70XC with something over 200k miles, still driving with the original 'white label' ETM and no problems.

I'd like to know how the 'software upgrade' manages to change the wiper position (which is the TPS sensor fixed to the throttle plate/position) without throwing off the AFR rich or lean, or spark timing which would probably impact tailpipe emissions and catalyst life, in order to accomplish the desired RPM/torque request.

[precopster]

If he unscrewed the black cap with 5 contacts on the end that contains the motor wires he would have killed the ETM.

You really can't do any preventative maintenance on these other than keep the externals clean. Inspecting both sides of the contact films would be a 4-5 hour job for a first timer. Better to purchase a contactless kit from eBay and fit it while you're in there.

The ETM firmware upgrade actually prevents limp home mode though performance is affected while there are throttle codes.

[abscate]

I thought the software upgrade basically allowed more errors before the ECM trips the ETS light and thus got Volvo through the 100k emission warranty period. I think it was all code and did not change the mechanicals at all

That’s all second hand knowledge , unconfirmed

[precopster]

I've scanned enough Volvos with and without the upgrade to know what difference it makes And I didn't quite explain what else new firmware can do.

On a C70 2000 I worked on the owner got a firmware update that fixed his limp home mode and more than 3 ECM codes even though the same ETM had zero codes and drove perfectly on my upgraded V70. Same ETM was used before and after on the C70.

Also the first time our NA V70 had an ETS light it went into limp mode with only one partially failed sensor. After a firmware upgrade that NEVER happened again and I continued to use it as a test vehicle for over 150 ETM repairs. I could drive down the road chugging and wheezing even with the wrong firmware and it could still hit freeway speeds.

It was frustrating because I couldn't duplicate customer's ETM faults when they had old firmware.

The same goes for my 2001 V70T5. It has new firmware and an ETM I drove on had no sensor 1 output whatsoever (failed processing side of board) but still drove reasonably well with codes.

Limp home due to ETM is ONLY a by product of old firmware. It just doesn't happen once upgraded. In fact upgraded firmware may even mitigate the need to replace the ETM at all so yes it was very clever programming from Volvo and I bet it saved thousands of ETMs from needing replacement during the warranty period.

[01_Nautic_V70]

So, now that my 2001 V70 T5 has a working transmission, she's decided to have engine trouble.

Yesterday, it was rough at idle immediately after starting and then eventually stalled. Restarting after that required full throttle.

Pulled out DiCE and found faulty Throttle Position codes. Erased, car started fine and things seemed ok.

Did the same thing this morning. Is this the beginning of the end for this ETM? It's a yellow sticker MM unit. I thought those had non-contact position sensors?