1998 V70 - Stalling and P0103 OBD-II code

PhotoMike · Post by **PhotoMike** » 08 Jul 2008, 13:36

First, a big 'Hi' to all the Volvo enthusiasts who took the time to contribute to this fantastic forum. After owning and repairing several Land Rovers, I understand and appreciate the value of a well maintained forum.

Now, its been about 2 1/2 years since I bought my '98 V70. It's the base model (non-turbo, 2.4L) but it is trimmed up with moonroof, leather, heat seats. Currently, the clock reads 122K miles.

It has not given me one issue since I bought the vehicle. Last Thursday (July 3), I started the car, which then idled rough at ~500 - 700 RPM and stalled in about 2-3 second. It started back up no problem and I was able to drive away. After 3 blocks, it stalled again while standing at idle. This time, it was having trouble starting back up. Finally, it came to life. As I was making my way home, I started losing power, as if my foot slipped off the gas pedal. This happened several times. Once I got home, it stalled in my driveway. It was about 85 F degrees ambient temperature.

The next day, I drove to the local public market with similar problems. Driving back, the problems continued to worsen. Giving some gas while starting the car seemed to help it get started and keep the engine turning. The V70 nearly died just coming down the street to my driveway. As soon as I pulled into my parking spot it stalled. Unlike the other instances I was unable to start the car, even with giving it a little gas while the engine was turning over. Once the car was cooled down, it would start again, but immediately stalled. It was about 87 F degrees ambient temperature.

I didn't want to take a chance stalling out in the middle of traffic, so I read the ODB-II code which was P0103 - MAF current output high. After some searching around the site here, I decided to disconnect the MAF to determine the effect. The car started right up afterwards, but the idle felt a little rough and would osciallate from ~600 - 800 RPM for about 20-30 seconds before evening out. Test drove the car for about 20 minutes and there was no sign that it would stall.

The only problem with driving the V70 in 'limp home mode' is that I need to be considerably more aware of how hard on the gas pedal I push starting from a stop. If I give it too much gas, the engine doesn't respond for a period of time from 2 seconds to 6 seconds, then the engine 'realizes' the gas pedal is depressed and the car begins to accelerate. Not terribly reassuring from a safety standpoint, but it gets me to work.

There are no other OBD-II codes.

I've been looking around the site here and it seems most folks get the P0103 with other codes.

My question: Is this a bad MAF sensor or can this problem be related to something else (i.e. engine vacuum hoses, PVC, other parts of the emission control sensor system).

I understand no one can diagnose the problem by listing the symptoms, but I am wondering if my particular symptoms suggest the problem is localized or if it is more nebulous.

-Mike

Post by **Ozark Lee** » 08 Jul 2008, 14:24

Mike,

P0103 is a MAF sensor circuit high. That can be either a bad MAF sensor, a bad connection to the MAF sensor, or a broken wire between the MAF and the ECU.

The curious thing is that it ran better when you unplugged the MAF but the code would indicate that it thought it was unplugged anyway. Perhaps the problem is intermittent and is within an acceptable range part of the time. The ECU kinda hates real sudden changes.

I would start off by cleaning the MAF connector with contact cleaner (cheap) before replacing the MAF.

...Lee

PhotoMike · Post by **PhotoMike** » 08 Jul 2008, 16:07

Lee,

Contact cleaner and a small dab of dielectric grease it ...still same problem.

I'm getting a little hope now. It sounds like the problem may be localized.

I may have time tomorrow to ring out the cable harness...but that's if I can located the wiring diagram/cable drawing w/ pin-outs for the ECU cable harness. MIJ posted some documentation I plan on skimming over tonight.

Hmm...a bad connector could be the culprit too. I should have checked the wiring harness connector, since exposure to thermal radiation is relatively high on the connector-side of the MAF sensor.

Are there any other potential causes besides the ones stated?

-Mike

PhotoMike · Post by **PhotoMike** » 09 Jul 2008, 18:28

Unfortunately, I couldn't find the necessary wiring schematic to wring out the harness. Reconnecting the MAF sensor caused the problem to reappear. Flexing the MAF connector on the wiring harness, w/ a reasonable amount of force, didn't have any effect.

I shelled out $90 for a new sensor from Erie Vovo. Their sales engineer stated that the part comes with a lifetime warranty.

Results of the new sensor install to come by Friday. Until then, I'll watch my gas gauge drop about 1.5x faster than usual.

-Mike

PhotoMike · Post by **PhotoMike** » 15 Jul 2008, 19:00

I got around to installing the replacement MAF sensor today. Idled the car for 20 minutes...no hesitation from the engine, stalling or any symptoms experienced with the original MAF sensor. Drove it for another 20 minutes, making sure to get in plenty of stop signs/lights to check the acceleration. Engine is responsive to any change in gas pedal movement. Engine temperature reach about 1/2 way on the gauge (normal), ambient temperature is around 79 F.

The final test comes tomorrow in 'real-world' traffic.

-Mike

Post by **Ozark Lee** » 16 Jul 2008, 07:45

Sounds like you fixed it!

Here is a link to your schematics:

1998 S/C/V70 Electrical

It is on a Polish server and it will take a while to download.

...Lee

PhotoMike · Post by **PhotoMike** » 17 Jul 2008, 19:25

Yup, it was the MAF sensor alright. No engine hesitation or abnormal behavior after 2 days of normal driving.

Thanks for the wiring schematic... it will be put to good use!

-Mike

Bill S70 T5 · Post by **Bill S70 T5** » 19 Jul 2008, 23:00

Well, It may be one of those good (or bad) luck things. I got a call from my wife whilst I was out of town. The S70 had just died on her way shopping, had to get a tow home and did I know how much they charge these days..I do now

Anyway ran her through how to use the diagnostic tool to get the fault code "P0103", researched the MVS site, came straight to this message and concluded that my MAF was dead or dying too.
You have a very greatful guy here and I'll be a contributor soon (I just bought a new MAF from FCP so may be after next paycheck

).

Thanks to everyone who add their experiences here, it makes life so much easier