2000 v70xc 2.4T idle problem/power problem *long*

[robbiewilso]

SO- replaced all the vacuum lines that may have been leaking. The way things are looking it may be the ETM failing after all since there seems to be no vacuum leak and now I have noticed that when it misbehaves the cruise control disengages or is unable to be engaged. Anyone got any ideas for me to try? Thanks!

[abscate]

There are a lot of ECM faults that disable Cruise, not just throttle body faults

Pull the label info (picture best) from your ETM and lets figure out how many miles are on it, when it was built

You will need to squeeze your phone under the Intake Manifold to get that pic

[robbiewilso]

the orange tag says something about being rebuilt and the tps sensor itself says 'Sacer' on the plastic end of it and is def the contactless upgrade.

[abscate]

I'm not sure how VIDA talks to a Sacer upgrade but that is probably the next set I would take

Try to get the ECM CODES read out with a good quality scanner, both active and pending ones

[robbiewilso]

thanks my local mechanic has a pro scan setup not the Volvo equipment but that is my next step.

[robbiewilso]

Ok I have had some time to think on this and here is something to ponder- After replacing the ETM the car ran fine for a month or so. My wife informed me of a vibration which after inspection I verified was a bad motor mount that had deteriorated. The vibration was noticeable but not bad. It also was a steady vibration and the idle was rock steady at the time as well. My question- could the vibration cause a poorly soldered ETM rebuild (with the Sacer magnetic sensor) develop an intermittent faulty circuit, causing the ETM to read wrong and causing my erratic idle? Or is it possible the metal/plastic round piece that sits on the throttle nut itself could be loose-especially if it wasn't tightened well and was subjected to some vibration? As mentioned no ETS light, and no CEL on my simple cheapo scanner.

[Ozark Lee]

My experience withe the ETM is that it will trip an ETS fault with even an otherwise unnoticeable problem. That said, intermittent wiring problems are the absolute worst to trace since it often isn't possible to recreate the condition that leads to the fault. Properly installed, I have heard nothing but good about the Sacer sensors but if the upgrade was installed by a previous owner then you have no idea what skill level they had in soldering.

The "Factory Upgrades" from the re-builders like Xemodex have a good reputation for quality but based on the comments around my old ABS module repair writeup there are widely varying skill levels when it comes to soldering when you get to shade-tree mechanics. Even with the same parts the results will vary based on the skill of the person with the soldering iron in their hand.

It would really simplify things if you could get some real time data streams recorded and look for anomalies. Short of that, and it is a chore, if you suspect a bad solder job then you will need to remove the modules and basically disassemble it to inspect. When I get that far I will re-solder everything but that is me and I am very skilled at soldering.

...Lee

[robbiewilso]

I have checked and I don't believe I have an idle air control module on this volvo. The last time I drove it the idle surged randomly and badly quite a bit- when sitting in drive at an intersection for instance it actually felt like someone was slightly moving the throttle which to me is a dead giveaway that the ETM is misbehaving and could be failing in other ways besides the Sacer sensor. I am of the mind to try another aftermarket rebuild (the one installed now is a BBA remanufactured unit so they are the ones that installed the Sacer sensor and are supposed to offer a lifetime guarantee on their part (i didn't purchase it directly from them though) so I may get in touch with them if an ETM resolves my issue.

[Ozark Lee]

Idle air control is a built in function of the ETM. It is all in software. There was a software upgrade that we a lame attempt by Volvo to cure its early failing ETMs. While it couldn't fix the actual hardware failures with the contacts in the sensors it did actually help on many fronts. It would be curious to see if your car had the software upgrade performed. As I recall it was a free upgrade from Volvo at the time but I don't know if it remains active. I don't think it ever reached a full recall status but it was at least some form or flavor of a TSB. The only way to know is to read the software version numbers through VIDA.

...Lee

[abscate]

Slight surging at idle is also a symptom of a vacuum leak - these cars are too complicated to diagnose by symptom - you need data. If you get the slight throttle bounce when you come off drive, thats a pretty good indicator of a bad hose somewhere.