Cleaned ETM, it's better.. but still not right

siouxperXC · Post by **siouxperXC** » 14 Mar 2018, 22:48

For the last couple years, I've driven my 2006 XC90 2.5T AWD and really enjoyed it. It has suffered from a rough idle but ran well at speed. I documented the issue, as I understood it, here (thanks to those that provided feedback) :
viewtopic.php?f=10&t=74366

About a month ago, my son was driving it when it went into 'Reduced Engine Performance' mode. I drove it in limp mode to OReilly's and read the codes (ODB2). About 25 codes were stored and after digging and digging, I came to the realization that the ETM likely needed to be cleaned. Today, I removed the ETM and cleaned it. It was extremely gunked up and I was excited to put it back together and go for a ride.

After re-assembling, it died twice trying to back out of the garage. After I restarted it the third time, it ran well for about 1.5 miles at speeds up to 50mph. Then it went into limp mode again. I pulled over and restarted it, but that didn't resolve limp mode. I drove it to the local convenience store, where I would have light. I pulled all of the fuses labeled 'ECM' and restarted. It ran pretty well for about 7 miles at speeds up to 65mph. It stuttered a couple times - I think each time under acceleration but I struggled to confirm this. Then, under heavy acceleration - when I thought I was out of the woods, it stuttered and went into limp mode. After I pulled over and restarted, it ran well again - all the way home. I assume the engine control has to re-calibrate when performance changes drastically. Is there something I need to do to re-baseline, or ??

Interestingly, when limp mode is cleared, the vehicle idles very smoothly. So smooth that I'm kicking myself for not cleaning the ETM years ago! This is interesting given what I thought was the previous issue - a dinged exhaust valve.

This brings me to y'all for more input. At this point, I'm amazed at how smooth it _can_ idle and perplexed at how it still can run rough too. It's hard to believe it could be something mechanical and I'm starting to wonder if I have a sensor that has become intermittent, or is there another electrical component / computer that could be acting up?

Thanks in advance for your help!

autoshiftin · Post by **autoshiftin** » 15 Mar 2018, 03:44

hi siouxperXC,
cliff notes: if any of your codes are fuel codes my post might help you. I had odd stalling from my newly purchased 04 S60 2.5T last summer. Similar to your "rough idle but ran well at speed". Mine idled sortof-ok but still stalled and cut out as soon as I accelerated even at slow speeds. I even had to push it to the side of the road a few times it stalled out on me. I did careful ETM cleanings, new plugs, Bosch MAF, checking the usual hoses, etc, but kept getting same stalling. The one OBD code that kept coming up was for fuel pressure sensor / circuit, so I replaced the regulator on the fuel rail... but the problem persisted and code kept coming up.. I eventually found it was from the fuel pump unit "PEM" that Volvo installed underneath the car and up on top of the gas tank. It was all corroded on the inside. Volvo controls your fuel pump with this little unit and if you are in an area with rust and corrosion issues (or if your car used to live in a corrosion area like mine did ) corrosion gets into the unit and fries it. Once i replaced it car ran smooth no more issues.. Names for it are Fuel Pump Driver Module, fuel pump control module, PEM, and are metal/non-metal tank specific. I bought a used one online from wrecking yard since they are spendy.

I notice you mentioned 25 codes were pulled at Oreillys but didnt list any of them, and that led you to clean the ETM. Please post some of your codes on here because they should be telling you something or at least some paths to go down. Also try to get your own OBDII scanner to pull codes yourself so that when you make changes or attempts at fixes you can check codes on the spot or when Oreillys is closed. (PM me if you can , I"m new on here I have an extra OBD scanner). Fuel trims and live data on a scanner can also cue you into important stuff that Oreillys can't help you on but invaluable.

Also because you have so many codes, it can also be electrical related. Bad/loose/frayed/missing/corroded electrical connections cause problems that are hard to figure out. Be sure you have cleaned and tightened your battery terminals (check voltage drop to verify), make sure all engine grounds are there/not missing and clean them and check with meter or test light. Even check / clean the alternator electrical connections. Then I would re-visit all your codes. Also at Oreilly have your alternator tested even if you do not have any problems with it, its free, and rules out that being the culprit. Then, maybe post some engine bay pics or zoom-ins of work you did or suspect is an issue, sometimes others can find stuff for you (like frayed or corroded battery terminals etc). There are lot of smart people on this site eager to help out.

Hope this helps.

Post by **abscate** » 18 Mar 2018, 04:08

That long list of codes will overload the human CPU. Clear them, then drive for a day and see what comes back,

How old are your spark plugs and coils?

siouxperXC · Post by **siouxperXC** » 20 Mar 2018, 21:49

OK... I was finally able to find the page where I had written down the codes.

Any clues here?

P0300 multiple misfire
P0303 cyl 3 misfire
P0101 Mass or volume airflow / circuit range
P2112 Throttle actuator ctl system - stuck closed
P0027 Exhaust valve ctl solenoid circuit range perf Bank1
P0301 cyl 1 misfire
P2111 Throttle actuator ctl system - stuck open
P1167 No DTC def'n found - see service manual
P0638 Throttle actuator ctl range Bank1
P2112 Throttle actuator ctl system - stuck closed
3100 Misfire at least one
3130 Misfire 3
120D Air mass
121B MAF sensor
926C Throttle valve
614B Exhaust camshaft control
3110 Misfire 1
929D ECM
925D Throttle valve
92CC Throttle valve
9270 Throttle valve
0121 Yaw rate sensor malfunction

thanks for any possible guidance!

siouxperXC · Post by **siouxperXC** » 05 Apr 2018, 16:43

Update!

A couple weeks ago, I disconnected the battery, as I was convinced I wanted to pull the ECM and check the connections for corrosion, etc. I was unable to completely slide the pink sliders without the removal tool, so I decided to check the spark plugs / coils. When I pulled the cover off, I found the ignition coil on plug 1 was loosely sitting on the plug.

Three years ago when this saga began, I took this vehicle to an independent shop for a wheel bearing and rough idle + MAF code. That guy lost the anchor bolt for the coil (he never told me). I discovered this not long after and ordered a bolt from the dealer but didn't get around to putting it in. I figured it was on pretty tight to the coil and the cover also adds some restraint.

Last fall the dealer was offering a CEL promo where they would spend an hour for free. They did a compression test, so I assume they had the cover, coils, and plugs out/off. Evidently, they didn't replace my anchor bolt either! I need to find their list of 'solutions'... I'm almost certain it did not include the throttle body.

After installing the bolt I had in the glove box and connecting the battery, I started the vehicle and it started to idle nicely!

I thought I had it fixed. I drove about 25miles and it ran great and idled smooth. I noted a couple stutters under heavy acceleration, so we'll keep an eye on that. I told my son it was fixed and asked him to take it to school the next day. He attempted and it went into limp mode again as he exited our neighborhood. So I had taken a huge step forward, in that, now the vehicle can run really well - when it wants to.

Over the past couple weeks, I've taken it for a drive on a regular basis to try and further isolate the issue. What I've found is that it runs great without going to limp mode if I let the vehicle warm up before driving. If I jump in and go (like my son did) it will pull the 'Reduced Engine Power' error and go into limp mode. Air temps have been consistently in the 20s-30s (F). The codes present when it goes into limp mode are P0638 - Throttle Actuator Control Range / Performance (Bank 1) and 9270 / 935D 'Throttle Valve'

Last night was the first time that it idled rough when I first started it and went into limp mode while it warmed up.

Yesterday my ECM tool arrived. I was able to drive the XC into the garage in limp mode and I successfully removed both the ECU/ECM and the TCU. There was no sign of corrosion on either the connector or the ECU so I plugged both back in and went for a ride. Again, it ran great! I put about 50miles on it last night and didn't have any issues with the CEL/limp mode. I ran to O'Reilly's and read the codes and it was empty (perhaps cleared when I removed it). I did notice a few 'stutters' again under heavy acceleration (they don't seem to correlate to shifts) and I'll get to those later..

Driving an almost healthy XC90 reminded me why I like this vehicle so much! I would appreciate any additional insight into what to try. I don't think I can simply replace the ECM, as they're programmed to the vehicle, right? It sure seems like something electrical or in the engine control given how it can run beautiful when it wants to. If spring would ever come, it will be interesting to see if warmer ambient air influences the perceived needing to warm up to run well.

O2 sensor? PCV service? Replace the throttle body?

Any ideas from the experts?

Post by **precopster** » 06 Apr 2018, 08:27

If you're getting throttle codes the logical thing would be to replace the throttle. On this model year they don't need adaptation except for Ign ON for 45secs then Ign Off and restart.

Of course plugs should be gapped correctly and of the correct heat range.

siouxperXC · Post by **siouxperXC** » 06 Apr 2018, 16:12

@precopster Thanks for the insight. I should have a new ETB Sunday and I hope that is the ticket. I appreciate you sharing the calibration timing. That explains why it ran poorly initially when I started after the cleaning, but well since..

Do you have a preferred plug for this engine? 4 of the 5 are OEM and the fifth was chosen off a local independent shop's recommendation (I don't recall off hand).

Post by **precopster** » 06 Apr 2018, 22:04

I have used these on all our Volvo turbos: https://www.amazon.com/dp/B000KKF4BK/re ... UTF8&psc=1

They're cheap, last well for the cost and easy to get hold of.

Try to use Matthews link to Amazon for purchases as it keeps the site running and pays for the late night coffees for Matthew!!

Post by **800artfreed** » 24 Dec 2019, 10:40

Any final solution? Thanks.

Post by **abscate** » 28 Dec 2019, 16:42

The coils have to be bolted firmly down with a clean M6 bolt/ surface for each coil, as the M6 bolts complete the secondary circuit ground.