2004 XC70 ECM 261A Lower Limit

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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

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goldmandan
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2004 XC70 ECM 261A Lower Limit

Post by goldmandan »

Ok i've been battling this damn code for WAY TOO LONG! I consider myself a very competent mechanic. I have about 145k miles on the car and have had it for about a year and a half now. We bought the car in NY and there the CEL would come on sometimes and then go off (during a period of a few months) and when we drove it back to Florida the CEL stayed on solid. The code ECM 261A lower limit. I've done a LOT of maintenance on this car and I still have the code. It first started off as ECM 261a (air intake leak), I replaced the PCV system, new hoses, even new coolant hose set up that goes under the intake manifold and into the thermostat housing, also new intake/throttlebody gaskets, took and replaced the throttlebody and cleaned out the used one properly before installing it, new spark plugs, fuel injectors, the vacuum hoses for the turbo, and into/under the intake are replaced, also replaced air filter and the MAF (not sure if replaced with new or used one). I am really coming to the end of my patience with this..... I have not replaced the o2 sensors, I will test them with my scanner (Autel Maxisys Pro) tomorrow and see what it shows. The 2004 of mine doesn't have the fuel pressure sensor on the fuel rail and have not bothered to check if the car has a PEM or not. I am wondering what this code could be coming from?

jimmy57
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Post by jimmy57 »

261a can be leaks in intercooler or any hose from turbo back to intake. If you see idle fuel trim at high additive amount while seeing this code for leaning to a lower adjustment range then intake leaks are likely. Intake leak will be a vacuum leak and make MAF signal low for actual consumed air while leaks between turbo back around to throttle will cause little change on idle fuel trim and drive lower part load and often upper part load to lower limit as air is passing maf and resulting AFR drives oxygen sensor to rich indication. If you drive fast and climb hills a lot then the upper part load fuel trim code should also be setting.
If you have no FPS then there is no PEM. You have full current fuel pump that runs full speed.

Test your O2 sensors with engine fully warmed up & idling a/c off. watch both when you create a substantial vac leak. The hose that faces block on driver's end of intake manifold is a good place for the leak. The sensors should both go lean, front over 1 and rear down to .2 V or less, in 2 seconds and at the same time. leave leak for 45 seconds. When you put hose back on to cap leak then both should go rich, front drops below 1 and rear goes up to .75 V or more, in the same 2 seconds simultaneously. A slow responding sensor is suspect.

goldmandan
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Post by goldmandan »

so you are still saying it could be an intake leak with the "lower limit" code? I changed the air pipe from air box to the turbo with a new volvo one. no help. I redid the intake gasket, the pcv system, the throttlebody clean and replaced gasket. All hoses I could see have been replaced, the vent valve that sits under the intake near starter motor has been replaced. The hoses from the intercooler look OK, I haven't replaced those. I will try removing the hose at driver end of intake and view O2 values and report back. any other tips?

jimmy57
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Post by jimmy57 »

It is possible. Leaks on intake can be vacuum idling and cause idle fuel trim to move rich while off idle it becomes of leak of already metered air and it has to lean to correct that. Less likley to be intake but not impossible.

goldmandan
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Post by goldmandan »

Ok front sensor is right at 1 no matter throttle position. Rear sensor goes up and down between .13 and .72 thought it was the front supposed to fluctuate and rear stay more constant

goldmandan
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Year and Model: 1999 S 70, 2000 V70
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Post by goldmandan »

Ok, I replaced the MAF with the one that originally came with the car when I bought it. Now the CEL is off!!!! I must have installed a defective "new"one and replaced a whole bunch of other parts just to find out the MAF was giving a lean condition!!! Man I feel ripped off!

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