Hi folks, first time posting at Volvo Forums, was previously a long time Saab owner (until the parts situation got ugly). Sorry this initial post is so long.

I have a 2002 V70 2.4 with 256,000 miles. Recently, the car started developing a random miss (maybe one cylinder misfiring? just a split second drop in power, but very quiet, no lurching) when driving between 55-75 mph. It wasn't tripping the CEL, so I figured it was some kind of anomaly.

A few weeks back, it started doing this miss at 75 mph every other mile on the interstate. When I stopped for fuel, and restarted the car, it seemed to be running on only 3-4 cylinders, the CEL was lit, and the display was reading the Urgent Engine Service Required thing. It was in limp mode, and would do only 15 mph.

After 3 restarts, and cooling off, everything on the DIM disappeared. I was pretty close to AutoZone, so I went to see if they could pull any codes, the only one they pulled was P0691.

In the last week, Tuesday, I could get it to duplicate only once, the most recent added P1026, which most internet searches point to the throttle body. The CEL, and presumably P1026, are gone again.

Some points that might help: The throttle body received the software update last year (but I believe is otherwise original). Most of the electronic modules are storing a fault code, I already had XoModex service the DIM last year; I think the CEM is going south and is next on the list. There is a slight random hum that can be heard when the car is at idle, don't know if it's electrical or related to the fuel system; also last week sounded like relays clicking under the central dash(?). The problem seems to be heat related, don't know if it's heat soak with the injectors or ignition coils. It is not easy to duplicate. The MAF is a Chinese made unit that the previous owner installed.

Any ideas where to start? I'm having a hard time believing the throttle body is the culprit...

Thanks in advance for the help!

 

Update- Wet, rainy day. Engine System Service Urgent showing up on DIM from cold start. Apparently does not require warmth. Current humidity is 89%.

Coming to conclusion that issue is electrical. Crack in ignition coil?

 

throttle body, MAF and idle air valve all clean? Could be a coil going bad or the connector but usually those throw off a 030x random misfire code. How do the plugs look? The P1026 is saying the ECU sensed the throttle position was off for a period of time - could be dirt or could be the ETM trying to compensate for something else (ie air/fuel mix stuff)... how's the fuel pressure?

 

Thanks, will check throttle body and such once it dries outside. When I bought this car, previous owner had second Chinese made MAF rolling around under seat, so was under impression that he kept changing them to meet Wisconsin emissions testing. Do I have IAC/IAV with the Magneti Marelli throttle body in an n/a 2002 V70?

Plugs look used. I should change them, they're at around 30,000 miles. The random hum does worry me as far as fuel supply goes, but when I hear it, car idles fine, no change in RPM.

 

P0691 Fan 1 Control Circuit Low
P0126 Insufficient Coolant Temperature for Stable Operation

You have coolant in the car right? Sometimes the sensor which warns you its low can go on ya.
You do look at the dummy temp gauge right? Though dummy gauges aren't always accurate. (my dads truck reads cold 100% of the time which isn't possible obviously).

Stutters and loss of power + limp mode. Check your MAF sensor, Clean it with some 99% alchohol or something similar, carefully use a Qtip or similar to wipe the sensor, dry and put back.
The MAF's get dirty and eventually throw a CEL which most garages will charge you to replace the MAF when 99% of the time they just need to be cleaned.

Then the plugs, check your spark plug gapping. 0.28 to 0.30 is acceptable.
Gaps widen over time on the plugs, forced induction cars need a small gap to spark proper with so much pressure in the cylinder.
Or as you mentioned get new plugs gapped right since you say yours are old.

 

Update 2- Found the reason for P0691- something got unplugged on the back of the fan shroud. Must not have clicked it tight when reassembling after AC compressor replacement.

Still sopping wet outside, readying to check MAF and ETM as it dries. Still starting in limp mode. Maxing 1500 rpm. Seems to run smoothish at this RPM though. Stumbles at idle, lights on DIM flicker.

Don: code thrown was P1026; coolant level fine and watched carefully after thermostat replacement in December.

 

Is the thermostat new or used?
P0126 would be thermostat related, once you cleared the codes does anything come back?

You should be getting more codes if its in limp mode, a miss fire code or boost related or MAF etc, something along those lines.

Definitely do as mt6127 says and clean that MAF real good. Be careful if you use Qtips to wipe it do not put pressure on any parts in it just gently spin the Qtip without pushing.
And anything liquid that dries fast works, I use 99% rubbing alcohol to clean that kinda stuff its cheap and works well to remove oils and grease.

(OILED FILTERS LIKE K&N WILL COAT YOUR MAF WITH THE FILTER OIL!)

While your cleaning the MAF just inspect your air filter, make sure all the hoses and pipes for air and vacuum are connected etc. Clear the codes and then try it out.

(Also it wont leave limp mode till you clear the codes, or until you drive for about 60kilometers if everything is ok the CEL will clear and limp mode will go away.)

Another thing that can cause a random miss would be coil pack(s), plug wires, and plugs. Even if the plugs are ok/new the gap may not be proper. 2002 is a ways back coil pack may be on its way out. wires too.
But the MAF is free to do, Though... When my MAF was dirty it threw a CEL for it with an appropriate code. I then cleaned it and the CEL went away 60km later. You say you don't have a CEL for it. Couldn't hurt to do it though.
Thing is a miss should also be sending CEL.... very hard to even begin thinking what it can be when the CEL codes don't say anything.

Maybe these cars have another sensor for coolant temp that's gone bad. Lookup Volvo V70 P0126 CEL see what guys replaced to fix it, you might find out there's two sensors or three or two thermostats even. Who knows with cars the engineers do silly things all the time that you don't expect.

 

Not to sound harsh, but you're getting the 1 and the 0 juxtaposed as you are reading this code. The actual reading is P1026.

Maybe to clarify further what it feels like, it sounds very much like point #3 in this post: http://www.matthewsvolvosite.com/for...ic.php?t=17252 EDIT: Except that mine is a normally aspirated 2002 V70 with the Magneti Marelli throttle body.
NOTE: Sorry in advance admin, please let me know if this outside reference is unacceptable.

At the moment, very stumbly at idle, engine shaking when looking under hood. Will only allow as much as 1500 rpm, but at 1500 rpm, car sounds smoother.

Throttle body is filthy on the intake manifold side. Will clean the MAF a little later today, when the drizzle and fog lift. Running a paper Mahle filter, so oil from a K & N filter should not be an issue.

There are no tuning upgrades to this car, outside of IPD swaybars.

 

Ooopse I didn't catch that.
Anything starting with P1 is manufacture specific. Google brings up nothing so far for me. Call Volvo and ask them what that code is.

 

So he's saying TPS or MAF in your link. I would still see if Volvo can tell you what the code is then. Chances are its one of those.

Got the code: P1026 VOLVO - Throttle Body Internal Fault

 

Thank you, Don. I couldn't find that Throttle Body Internal Fault point when Googling myself. And it was something I was afraid of, because that means now both that and the Central Electronic Module need to be repaired. On a car I paid $1300US for (although, it has been fairly solid so far for the 42,000 miles I racked up).

 

When things break they're expensive yeah. I got my S80 T6 for $800.

Leaking coolant - radiator $280

Alternator draining battery - new $380, used $175 I'm looking into having it rebuilt hopefully for the same price as used.

Needs brakes somewhat soon, volvo wants like $600 for pads front and back so I'll find some random cheap ones.

It's got some other issues too. But I knew, the seller was up front about it all. I got a decent deal $800 canadian and some elbow grease and a few parts it will be worth $3,500

Besides parts price volvo makes you do all sorts of things like programming throttle bodies etc. Things that really shouldn't be needed. Oh well.

 

Ugh, my limp mode speed is 5 mph; and I have 7 go blocks on very busy streets and to cross a state highway to get to Autozone...

MAF cleaned. It was pretty filthy. Car started and ran fine Monday, today, problem back all over again. It's 55 F degrees out and sunny. It's not hot, it's not damp, so issue is totally random now instead of environmentally based.

 

So MAF is done, but the Throttle Position Sensor and throttle body havent been looked at?
P1026 throttle body internal fault so it's un happy about that probably still.

Unless your MAF has kicked the bucket shortly after the cleaning.

 

Just took it to Autozone in limp mode, here what the scan says:

P0300
P2177
P1026
P0691 (I thought I took care of that one with the connector on the fan shroud)

HELP!

Of course, their computer is trying to sell me an ignition coil, but if it can't even isolate the cylinder...

 

In the span of half an hour (I realized that I forgot to turn the hazard flashers off) I restarted the car, and it runs normal again.

*bangs head on wall in frustration*

 

XD sorry my email wasn't working right so I didn't see your first post. Atleast you got it XD.

 

Actually, I didn't. That's the aggravating part of this issue. It's totally intermittent and random, which leads me to the conclusion of bad electrics/electronics. If it was a plugged injector or air filter, I think the problem would be constant. The problem reared it ugly head the very next day, back in limp mode.

It's raining right now, and for as random as the problem is, I wouldn't be surprised if the car runs normal. But at this point, I don't trust the car 4 blocks from home. So frustrating.