ETM Compatibility Question

[jcb]

Sent a couple of replies to your latest, Any thoughts ?

[precopster]

I've tested a variety of ETMs on various XCs and they have all allowed the pedal to operate the throttle plate with ignition in POS II and only during that small window of time (6-12 seconds after key is placed in Pos II)

I repair about 1.5 ETMs per week (that's my average so far). Most of them get sent to me and I test them using my own XC or my V70. I also work closely with many garages both here and interstate. None of them have reported a lack of plate movement during power up unless the unit is dead. If they do I suggest scrapping the ETM and getting a good used unit or a new one.

Testing ETMs is best done by Vida Dice as there are afew different tests of both ETM and MAF through this interface.

[precopster]

By the way you can start the car with the used unit electrically connected and the original unit still plumbed in to your engine. The car will starve for air but may still idle; albeit lumpily. During this time you should see the pick and pull unit responding to pedal movement.

You won't do any damage to your engine as long as it's not driven that way.

[jcb]

Mike,

Thanks for the input, even though it looks like my spare is likely shot. Not a big loss if it is - $40. I have to say I was very encouraged when it fully closed on power up (I'm assuming that was the normal direction of movement). Suspect I'll give it one last try by doing the check you suggested with the engine running. I considered doing this, but backed off for fear of screwing something up.
I also considered going to the trouble of dropping the intake hose off my ETM to see how it responded with the ignition switch on. In fact, it probably makes sense to do that anyway to see if mine needs a cleaning. As my symptoms are so mild at the present time, it's possible there is enough crud buildup after 13 years/78,000 miles to cause some of them.
If my spare is no longer a spare, I'm pretty sure I'll try to take it apart to take a look inside, even if I can't get it back together. I recall seeing a few threads with pictures as a guide. If you are aware of any good threads on how to do this, please forward them to me.

I will report back on further developments.

Thanks Again for Your Help

[jcb]

UPDATE -

I decided to drop the hose off of my installed ETM and if nothing else give it a cleaning without removing it from the car. To gain access I removed the cooling fan, an easy 10 minute job. I also disconnected a few other things, but they were probably not necessary. The throttle plate was pretty gooked up, so I cleaned it as best I could with throttle body cleaner on a rag. Took quite a while because I avoided spraying directly into it as has been the advice of many.
Before putting things back together, I decided to turn the ignition key on and see how the plate behaved when the ignition key was turned on. As with the spare I had tried, the plate closed for about 10-14 seconds and then opened when it powered off. So I tried it again, this time fully depressing the gas pedal when it was in the powered up time window. The result was no plate movement, just as with the spare when tested. Several repeats gave the same result.
I decided that since I was halfway into the process, to go ahead and install the spare. I did and the car started and idled OK. I then revved it up to a couple 1000 rpms and it seemed OK and settled back into a smooth idle. At this point I quit for the night, not wanting to push it since I hadn't put things totally back together. I'll do that tomorrow.
So while the case is still out as to how this spare will behave on the road, it is clear that at least on my car the throttle plate does not respond to pushing the pedal when in the power up mode. I have no doubt that Mike P's experience has been different. My only conclusion is that at some point Volvo, for safety reasons, made the throttle plate movement part of the same interlock that prohibits ignition and fuel unless it senses a running or cranking engine. Seems like a logical thing to do.

So I'm again encouraged, at least for now. Will report back tomorrow on what happens.

[precopster]

Very odd behaviour from your ETM but where Volvos are concerned nothing surprises me any more.

It may need a ECM reflash causing odd behaviour when not running. The only way is to send the car in for a ECM reflash which will probably make it behave more like most of the other cars out there.

Not really any cause for concern; it just makes testing the unit a bit of a pain.

If you have post '06 software in your ETM you can run a sweep test through Vida Dice which will give you a graphical performance chart of the behaviour of the sweeping films. This is the best way to test other than actually driving and running the car.

[jcb]

Mike,

Yeah, know what you mean by "nothing surprises me anymore". In my 50+ years of tinkering with my cars (starting with my beloved TR-3), I've seen enough deviations from "the norm" to make me hesitant to state anything as applying 100% of the time.
Don't know if I have the software you are referring to. I do know that a software upgrade was done in June '06 at the height of the ETM controversy. Dealer invoice shows : 17 Recall 301 WV94 no charge and 1 30785453 9 ETM/ECM P Upgrade no charge

Of course I have no idea of what upgrades were done to the donor car that the spare ETM came from. I have to assume that since it is a 2006 yellow label ETM, that car would have had the latest software installed at that time. I have no idea of whether there could be a "software conflict" as a result. This kind of stuff is way beyond my pay grade. In these situations, I always figure that "the proof is in the pudding". If the cars starts and runs well, I'm done. If my particular car has a peculiar aberration, it is only important that I know it (and remember it if there is a next time).

I'll be putting the car back together a little later today, and will post the results.

Thanks Again

[jcb]

UPDATE #2 :

Just finished putting everything back together and coming back from a half hour test drive. I'm happy to report "so far, so good". The engine runs fine with a very steady idle. The car accelerates normally and had no issues driving at expressway speeds. While I realize that things could change, I feel pretty confident in saying that the installed spare is compatible with my car - just as Mike (Precopster) predicted early on. After some research he also thought that there may be no need for a dealer software download. That was one of my secondary goals. So far that also seems to be the case. Thanks Mike !

I will report back if something changes.

Also, I mentioned that I tried to clean my original in place without removing it. I'm sure there are posts out there on how to do this properly, and I suspect my way isn't one of them. Not only did it take a lot of time, it didn't get the job done very well because you can't get very far above the throttle plate area. Once I figure out how to post pictures, I'll show you several several that demonstrate this. You really need to get it out of the car to do it right. Instead of an impending ETM failure, the throttle body was certainly dirty enough that this could have been the sole cause of my rather minor idle issues. I will clean this one up and keep it as a spare, even though it has 78,000 miles on it. In the end, I'm just feeling a lot more comfortable seeing a yellow tag in there instead of a white one.

As noted I changed the ETM without removing the intake manifold. I took some pictures which I will try to post along with a few tips I learned along the way. Probably the best place to do this is in a longstanding thread on this forum "how do I remove an ETM" by Don Wilson.

[sdelasal]

hi - is it possible that this difference in throttle plate behaviour in those first few seconds can be attributed to whether the ETM has been updated with the 'software download' or is original? For example:
1. Original software: no throttle plate response unless engine is cranking
2. Revised software - allows throttle response within first 6seconds of power up?

Just a thought ... i'm trying to solve a problem vehicle. One replacement etm I tired responded to the pedal within 6 second window, like the original, but car still exhibited fault. Second ETM did not respond to pedal & i've yet to try that with engine running. STeve

[precopster]

No all ETMs whether programmed to the car correctly or not should respond within 6 seconds of turn on if that's what your car does with another ETM. When ignition is turned on 12V is applied to the thick green wire (the earth is thick brown wire)

You can test the ETM by applying power with test leads to the previously mentioned wires while disconnected from the car.