ODBII Trouble Code---"P1171"

[slackjawed]

My C70 failed inspection today in NJ for emmissions. I wasn't totally surprised because the "Check Engine" light came on yesterday although I wasn't sure why.

The printout the DMV gave me says the trouble code present was "P1171" but no description of what that means.

Does anyone know what "P1171" corresponds with?

Thanks,
Gordon

[rothe]

I had that code a while back. I recall it being related to a defective Mass Air Flow (MAF) sensor, which was replaced under warranty at the time.

But I just checked All-Data, and it shows P1171 as "Long Term Fuel Trim (Upper Limit)," as opposed to P1172 "Long Term Fuel Trim (Lower Limit)." Interestingly, both translate to the same VADIS code (ECM-261A). The upper limit code has to do with a lean condition, and the lower limit code is a rich condition.

Only for the lower limit code (P1172) do they suggest that a new MAF sensor is one of the suggested fixes. For what it's worth, that's a very common failure point on our cars.

Among the upper limit code causes, they mention the evaporative canister purge valve as being one possible source of a vacuum leak which would cause this code. The CP valve is another very common failure point on our cars.

The CP valve costs a whopping $18 from FCP Groton, and is very easy to replace. It's mounted on the air filter assembly. If it were my car, I'd poke around for loose or cracked vacuum lines, then I'd replace the CP valve, and then I'd clear the code. If the problem recurred, I'd throw a new MAF sensor on it in hopes that "this guy on the internet isn't totally senile and is actually on to something." The MAF is also pretty easy to replace.

In all cases, you're going to need to clear the code with a code reader. See http://www.jimrothe.com/volvo/....html.

[blf]

had 1172 on my C70 and it was the MAF

[MadeInJapan]

Doesn't a loose gas cap also produce that code? Worth checking and cheapest fix of all!

[rothe]

Quote, originally posted by MadeInJapan »

Doesn't a loose gas cap also produce that code? Worth checking and cheapest fix of all!

No. That would be one of the P045x codes that have to do with evaporative emissions leak diagnostics.

[slackjawed]

I'm totally ignorant on this entire topic, so I might be totally off base with this comment. But in my internet research on this code, I've come across quite a few articles that describe this problem as "Throttle Actuation Potentiometer Sign.2 Range/Performance". I don't know what this means, and perhaps each manufacturer assigns it's own code for specific problems. But as I embark on getting this repaired, I want to have as much info as possible.

[rothe]

The P0xxx codes are all standard among OBDII systems, but the P1xxx codes are manufacturer-specific.

Hey -- I just realized that you're not that far away from me. (Exit 102 off the Garden State Parkway.) And I happen to have both a code-reader/reset-tool, and a spare, known-good purge valve of the kind that I described earlier. Trying it out will be darned cheap, if you feel like taking a ride. (The valve was tried for 2 days in order to fix this: http://forums.swedespeed.com/zerothread?id=42487.)

I'd want my cost back on the valve if you actually need it, plus you have to buy me a beer!

Shoot me a private e-mail if you're interested: http://www.jimrothe.com/contactme.html.

[slackjawed]

Just had this fixed, finally. They replaced the rear oxygen sensor and reset the Check Engine light even though the Volvo dealer they consulted told them 90% of the time it is the front sensor. 48 hours later the Check Engine light it is back on.

They claim the next step is the front oxygen sensor and the final step is the mass airflow sensor.

Any bets on which is?

Thanks,
Gordon


Modified by slackjawed at 10:13 AM 8-27-2005

[RD]

p1171 was my maf. I replaced it myself and cel never came back.

[JRL]

Either or.
Interesting they replaced the rear sensor, the front goes bad first as a rule

[MadeInJapan]

...they're just trying to make some money.

[slackjawed]

Actually, they are making no money on it. They guaranteed it would pass inspection, so until they get that CEL off, it's all on them. The only thing I can figure is that the rear sensor is cheaper than the front and they hoped it would cost THEM less if they fixed it with that (or I took it to inspection before the CEL came on again.....)

The car goes back to them on Friday so I will keep you posted on whether or not the front sensor change is the correct one or if it needs a MAF.

-Gordon

[jemc70]

I was getting P1171 and my ECU would go into "limp mode".
Replaced the MAF sensor.....car is running great.

[slackjawed]

My car isn't in "limp" mode, but I have a feeling that the engine computer is cutting back on power. When I do push it hard, I get what I would call a slight bucking as it reaches higher rpms.

The car is going in today, and they already told me they are replacing the front oxygen sensor. I guess they are trying to avoid replacing the MAF which I assume is the most expensive of the three items they are trying.

[rothe]

Quote, originally posted by slackjawed »

I guess they are trying to avoid replacing the MAF which I assume is the most expensive of the three items they are trying.

If this car came from a Volvo dealer, then I would propose that they're following that oh-so-common tactic among Volvo dealers of throwing warranty money at parts and labor, at the obvious expense of your time and aggravation. If this car came from a non-Volvo dealer, then they're probably just not familiar with just how common MAF sensor failures are on this car.

You've had four people in this message thread saying that this is a MAF sensor problem. Have you bothered to share this with the dealer? You might save yourself some time shuttling that car back and forth to the dealer, and they'll save themselves the expense of purchasing parts that don't need to be replaced.

BTW, the MAF sensor from http://www.fcpgroton.com costs the same or less than either the front or rear O2 sensors.

[slackjawed]

This is a non-Volvo dealer. I have indeed shared this info with them, but for whatever reason, they prefer to replace the oxygen sensors first and the MAF sensor last. As this is their money, I really don't have much of a choice other than to sit back and watch them fumble through it. It is an inconvenience to be sure, but the trouble is worth it to save the several hundred dollars+ it would cost to have this done myself at a Volvo dealership.

[slackjawed]

Well, one day later, the CEL light is back on. If nothing else, I got free front and rear oxygen sensors out of this.

Next week it goes back for the part you all told me (and I told the dealer) it really needs: a new MAF..............

[slackjawed]

Finally, after all this time, the MAF has sovled the problem (I hope). Got the car back Thursday evening and so far, no CEL. Thanks to everyone for your input!

[askulte]

Bringing this post back from the dead...

My fiance's Volvo V70 turbo set off the SES light. Got it scanned at Autozone, and it was P1171 - Rotor Fault or fuel trim. Some of you guys replaced the MAF sensor to get rid of this... Rather than burden me with more diagnostics, she took it in to the local Volvo dealership, who for $100 of labor, determined it was a bad front 02 sensor (it's a 2000 with 25,000 miles) and would be a $450 repair (.6 hours labor + $$$ part). I called the service manager asking how it was determined, as the 02 sensor didn't set of any of it's normal faults (low or high voltage, slow response, etc...). He explained that the fancy dealer computer walks the tech through a troubleshooting tree, and when the tech didn't notice any vacuum leaks (my theory), the computer told him to replace the O2. Is it possible that at 25,000 miles, the 02 sensor is bad, without a fault getting set off? Should I spend the $180 and buy a new sensor from FCP? I'm thinking I should buy a factory service manual and an OBD2 scan tool, and checking to see what the MAF is reading at idle, and if it's in spec. The dealer tech said fuel pressure was normal, so it might rule out a clogged filter or weak pump. Anyways, I think the dealership is full of it, but I've been wrong before... We've had the Volvo 2 months, and already it's had to go to the service department. Hopefully not more often!

BTW - If any of you guys track day your volvo's (the car has really grown on me, but she won't let me take it to limerock on thursday. Doh!), I'll be there with the turbo Camaro on Thursday 6/21 with the http://www.cartct.com time trials...

Andris

[adale]

Look people. All the codes from P1171 to P1174 all have to with MAF. I simply took mine off and cleaned it with a 6 dollar spray from discount. In 48 hrs, my C70 was running perfect again. And just in case you guys are wondering, I do know what I'm talking about because my friend is a mechanic at Central Florida Eurocars in Lakeland, Fl and he told me what to do and how to do it. LATES

[askulte]

adale - What spray was it? Just a generic electrical contact cleaner spray or a electrical motor cleaner? The GM cars use a fragile hot wire MAF that's very sensitive to deposits from cleaner sprays like carb or brake clean, but Volvo's are new to me...

Andris

[adale]

Yes. Volvo has the same in their MAFs. You have the pay the side with pipercross design on it and then let it dry.

[beefeater12]

I recently did mine two/three/four weeks ago. CEL went off two weeks after i cleaned it. Been running great ever since. I used the MAF Cleaner. 7 bucks at advance auto.