Login Register

2006 XC70 LTFT problems (ECM212C and ECM21EC) Topic is solved

Help, Advice, Owners' Discussion and DIY Tutorials on Volvo's stylish, distinctive P2 platform cars sold as model years 2001-2007 (North American market year designations).

2001 - 2007 V70
2001 - 2004 V70 XC (Cross Country)
2004 - 2007 XC70 (Cross Country)
2001 - 2009 S60
2003 - 2007 S60 R
2004 - 2007 V70 R

Post Reply
ortho stice
Posts: 14
Joined: 30 November 2015
Year and Model: 2006 XC70
Location: Pittsburgh
Been thanked: 5 times

2006 XC70 LTFT problems (ECM212C and ECM21EC)

Post by ortho stice »

This thread is about a 2006 I picked up for very little money because of a persistent check engine light. The only codes in VIDA are for long-term fuel trims being high, ECM212C and ECM21EC. The car had trouble holding idle when I bought it. I put a spare ETA on and found the original throttle horrifically dirty. This solved the idle stumble but the codes persist (unsurprisingly).

The only other thing I notice is the MAF reading at idle hovers around 9 kg/h (8.5-9.5) which I've read is low for these cars. The previous owner put a new MAF in (it certainly looks new) but I don't know from what manufacturer and the OEM MAF did not come with the car. Previous owner claims the entire intake was smoke-tested and the plastic intake pipe between airbox and turbo was replaced (it's an obviously new piece). Long term trims seem normal based on the current data, the frozen state reading when the code initially came up was at 19.5% at like half throttle around 3k rpm (I think I was accelerating). Fuel pressure is dead on 400kPa and the pump's at like 35% duty cycle at idle with half a tank. Some searching around other forums suggests others with these codes typically experience terrible fuel economy, but I'm showing 19 average on the instrument cluster and calculated 23 on a recent long highway drive.

Any thoughts? I'm used to LH2.4 and have never messed with a P2 car until now. Picture of the offending car at the top of my unplowed driveway which it glided up without any problems:
Image
Last edited by ortho stice on 10 Feb 2025, 08:30, edited 1 time in total.

vtl
Posts: 4723
Joined: 16 August 2012
Year and Model: 2005 XC70
Location: Boston
Has thanked: 114 times
Been thanked: 603 times

Post by vtl »

Replace both oxygen sensors. Their life span is 100k miles, as Bosch says (who makes them).

ortho stice
Posts: 14
Joined: 30 November 2015
Year and Model: 2006 XC70
Location: Pittsburgh
Been thanked: 5 times

Post by ortho stice »

That's definitely on the agenda and I can see how that could impact things. Any reason to worry about the low indicated flow through the MAF at idle?

vtl
Posts: 4723
Joined: 16 August 2012
Year and Model: 2005 XC70
Location: Boston
Has thanked: 114 times
Been thanked: 603 times

Post by vtl »

ortho stice wrote: 10 Feb 2025, 08:31 That's definitely on the agenda and I can see how that could impact things. Any reason to worry about the low indicated flow through the MAF at idle?
Vacuum leak. Smoke the intake. Pay extra attention to the vicinity of PTC (PCV long heated pipe/hose ends there by the turbo).

What part number is on MAF. Should be Volvo original or Bosch

https://www.fcpeuro.com/products/volvo- ... 0-31342414

https://www.fcpeuro.com/products/volvo- ... 0280218088 Check the part number.

ortho stice
Posts: 14
Joined: 30 November 2015
Year and Model: 2006 XC70
Location: Pittsburgh
Been thanked: 5 times

Post by ortho stice »

A smoke test will have to wait for now; I do not have the equipment. The replacement MAF they put on is an NTK brand (one of the cheaper options on rockauto). Another interesting element is that I took the airbox lid off to look at the MAF housing and element and there is organic debris sucked against the screen of the MAF housing. The air filter is brand new and the airbox is clean, but I wonder if something happened there that wrecked the first MAF, ie rodents or something.

I watched my O2 sensor values in VIDA after a quick drive. They seem to respond the way I'd expect; stabbing the throttle in neutral spikes the front way up and the rear voltage drops in response. I'll probably still replace them since they are unknown age on a 181k mile car.

scot850
Posts: 14864
Joined: 5 April 2010
Year and Model: 2000 V70 R
Location: Calgary, Alberta, Canada
Has thanked: 1834 times
Been thanked: 1709 times

Post by scot850 »

Not sure how stuff got passed the filter unless the car sat for a long time and mice managed to chew through the air filter.

If there is debris up there and the repair shop did not mention an issue, I would suggest it may have been in the lower section and they did not clean the air box out when replacing the MAF. Possibly they removed the top and bottom of the box as well as the filter and then re-assembled and crap got up there. I would suggest trying to vacuum it out as best you can.

If that is what happened that is careless work by the repair shop.

It will be interesting to see how the aftermarket NTK MAF works out. If you plan keeping the car, I would suggest seeing if you can either pull or find a used OE MAF and keep it on the shelf as a back up should this one fails early.

Also let us know if/when you replace the O2 sensors how that works out.

Good Luck!

Neil.
2006 V70 2.5T AWD Polestar tune
2000 V70 R - still being an endless PITA
2006 XC70 - Our son now has this and still parked in our garage
2003 Toyota 4Runner V8 Limited
2015 Kia Sportage EX-L - Sold
1993 850 GLT -Sold
1998 V70 XC - Sold
1997 Volvo 850 SE NA - Went to niece in California - Sold
2000 V70 SE NA - Sold

ortho stice
Posts: 14
Joined: 30 November 2015
Year and Model: 2006 XC70
Location: Pittsburgh
Been thanked: 5 times

Post by ortho stice »

This weekend I replaced the radiator as it appeared to be weeping from the driver's side end-tank and I had been experiencing coolant loss every 500-600 miles. I ordered the Volvo OEM radiator because I had read about the aftermarket ones not having the reinforced hose barbs. Earlier this week the rate of coolant loss accelerated rapidly; the low coolant light was coming on after 20 minutes of driving. When I took off the upper radiator hose I found that it was loose! It was loose because someone had installed one of the aftermarket radiators and torqued down hard on the hose clamp which had totally deformed the hose barb.

Anyway I tell this story because of course I took the airbox out and found that the clamp holding the inlet pipe to the MAF was completely loose. I ran out of time tonight, but I wonder if unmetered air was getting pulled in from there. I disconnected the battery when I did the radiator, just in case, so I'm starting from a blank slate with codes.

ortho stice
Posts: 14
Joined: 30 November 2015
Year and Model: 2006 XC70
Location: Pittsburgh
Been thanked: 5 times

Post by ortho stice »

Okay; I raided an '06 S80 2.5T for some parts today at the U-Pull. First of all; I pulled a clearly aftermarket MAF and housing off the car and put it on my XC70. The housing that was on the car was even more clogged than it had appeared when I first looked at it in the airbox, it had dead bugs and other debris embedded in the grid. Anyway my idle MAF flow is now 11.9-12.2 kg/h so I'm calling that resolved. I also grabbed a PEM as a spare and some seat trim.

Before I swapped the MAF, the LTFT code had come back. Here's the initial state data I screenshotted:
Image

I honestly don't even know what to make of that. Codes are cleared for now so I'll see what comes up, if anything.

User avatar
abscate
MVS Moderator
Posts: 35267
Joined: 17 February 2013
Year and Model: 99: V70s S70s,05 V70
Location: Port Jefferson Long Island NY
Has thanked: 1497 times
Been thanked: 3809 times

Post by abscate »

I would guess those 99% fuel trim numbers are spurious data.

The 23% total trim is pointing to vacuum leaks or unmetered air.
Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 XC90-in-Red
Link to Maintenance record thread

vtl
Posts: 4723
Joined: 16 August 2012
Year and Model: 2005 XC70
Location: Boston
Has thanked: 114 times
Been thanked: 603 times

Post by vtl »

abscate wrote: 20 Feb 2025, 02:33 I would guess those 99% fuel trim numbers are spurious data.

The 23% total trim is pointing to vacuum leaks or unmetered air.
99% is for Bank2, which I-5 apparently does not have. STFT 3% and LTFT 20% was definitely a problem. Either a leak or bad MAF reading.

Post Reply
  • Similar Topics
    Replies
    Views
    Last post