Bucking and Stalling, What Is My Next Step?

White Chocolate · Post by **White Chocolate** » 16 Mar 2017, 10:39

So I have a 2005 Volvo S80 2.5T AWD with 138,000 miles.

About a month ago, I was driving. When I came to a stop, I felt a shudder and the car threw a code, the infamous P0101 Mass or Volume Airflow Performance Problem.

I replaced the Mass Airflow Sensor and all seemed well for about a month.

Yesterday, I was driving and all the sudden the car started vibrating and stalling and the check engine light came on with the display message Engine Service Required. I pulled over and pulled the codes. It was the same P0101.

I was only about a mile from home so I restarted the car and tried to drive. Now it was out of control. It was really vibrating and bucking and the triangle turned red and the message changed to Reduced Engine Performance.

Reduced I wished. It wouldn't even go above 3 - 5 miles an hour. And it would stall out completeley. Only stopping and restarting would get it to go another few hundred feet. Needless to say, it was a pain getting home into the driveway.

I reset the codes so I could start it again today to see if the same codes triggered.

When I did a cold start, I know something is wrong because instead of starting with a higher RPM (it was 32F this morning) it started at 600 - 700 RPM and stayed there.

Anyway, here are the codes I pulled this morning:

P0101 Mass or Volume Airflow Circuit Range / Performance Problem

P0100 Mass or Volume Airflow Circuit

P2402 Evaporative Emission System Leak Detect Pump Control Circuit High

Any ideas, guys, on what I should look at next? As I said, the Mass Airflow Sensor is new. What should be my next step?

I don't know anyone with VIDA and if I take it to the closest Volvo dealer (which is an hour away) I know I will be looking at $$$$. If there is anyone around the Pittsburgh / Monongahela / Belle Vernon area with VIDA/DICE I'd be grateful for any help.

Any ideas on what my next troubleshooting step should be? I'm scared to even drive it for fear of it stalling out in traffic.

The P0101 is the most recurring code it throws. The P2402 is new as of this morning. Can the new Mass Airflow Sensor be bad after only a month? What is the next thing to look at after the Mass Airflow Sensor?

Thanks,

Matt

Hendoo · Post by **Hendoo** » 16 Mar 2017, 23:35

I wish I could help, but I don't have VIDA and I'm on the West Coast.

Hopefully somebody nearby will be able to help.

But... have you considered a local indie Volvo specialist instead of a dealer? Much less hassle if you can find one nearby and certainly cheaper...

-Hendoo

Post by **jpkuntz** » 17 Mar 2017, 08:05

I would check air delivery pipes, especially between AMM and throttle body.

Legofan · Post by **Legofan** » 18 Mar 2017, 20:05

P2402 "Evap leak high(large)" means you have an intake hose loose. This will cause the car to run like this and throw codes since the MAF is being bypassed. Check all of your intake piping.

White Chocolate · Post by **White Chocolate** » 20 Mar 2017, 12:49

So the problem has been solved. I want to thank everyone who advised me on what to look for, as it will help in the future as the car continues to get older and things continue to deteriorate over time.

In this particular instance this was probably that one-in-one-million chance thing but can you believe the new Bosch MAF was DEFECTIVE?

As you might have read in the original post, when I started having the error code for MAF, I ordered a new one and installed it. Things ran OK for a month then it was back with the same error and then really rough running and stalling.

I never thought that the new Bosch MAF would be to blame but in fact, that was the problem.

I found it by hooking up my OBD II reader and using Torque.

I noticed that the cubic feet per minute reading (CFM) for the Mass Airflow Sensor was reading zero, meaning, the ECU had no idea how much air was flowing into the engine. Thinking this couldn't be, since it was a new MAF, I cleaned the connectors and tried again. Still zero. Still rough idle and stalling.

Went and picked up another new Bosch MAF, plugged it in, car started perfectly. OBD II and Torque began accurately reporting CFM air flow through the new MAF.

So, long story short, returned the defective MAF and am mad at myself that I didn't take a little more time initially and look at all the Torque specs when the problem first started.

But then, who expects Volvo / Bosch factory parts to be bad out of the box? That is where I messed up. Had I hooked up Torque right away, and taken my time, I would have seen that the CFM was at zero days ago and saved myself some aggravation, lol. I just falsely assumed that the new Volvo / Bosch MAF couldn't have failed in a month.

Thought I'd pass it along in case any of you do a repair with a new, factory part, and still have the same issue. The new part could be that one-in-a-million that is bad out of the box.

Ironically, it has been a few days now and it continues to run just fine. Idle is smooth, power is back, no error codes.

850TurboTurtle · Post by **850TurboTurtle** » 13 Feb 2018, 20:48

For the record, I bought an 05 S80 with this same problem apparently, and it turned out to be the throttle body. I found an OEM part made by the same company that builds it for Volvo, for half price of a V branded unit, put it in in 2 hours, and it runs great. Sticky throttle body. Anyways, may not always be this problem, but the bucking, limiting at 5mph, etc, was limp mode. Once a new unit was in and it relearned, it was happy and smooth as can be.

P2Apprentice · Post by **P2Apprentice** » 05 Sep 2020, 09:12

Hey White Chocolate,

I'm new, have similar symptoms on P2 S60 on 1 occasion on a damp foggy morning this spring driving through da'burgh. Thought maybe you would have suggestions -- particularly if you found anyone with VIDA nearby would be handy -- but I'm too new to DM you for direct guidance. You mention "Torque" but I'm not sure what that is.

I have read that the symptoms could be many things: (MAF, throttle body, Plug/Coils, etc) Not sure where to start diagnosing without VIDA.

Inexpensive (Walmart OBD-II/EOBD HyperTough HT309) code reader reports no codes. No CEL at present.
I pulled the module information from the dash but so many things were triggered and they were so generic it really didn't help me to diagnose. Pretty sure it was TCM, ECM, (.... and a bunch of others that seemed unrelated) being reported on the dash console.

Event Description:

Stumbled or maybe missed a couple times at low speed low speed/rpm approaching traffic lights on level on this morning.
It was such a subtle bump/thump I thought maybe I imagined it the first time, got a bit worried the second time.

Then, immediately after green on the traffic light where I felt it 2nd time, I barely made it up one hill big hill, your description of:
"Now it was out of control. It was really vibrating and bucking and the triangle turned red and the message changed to Reduced Engine Performance." is pretty much exactly describing what I experienced. I definitely recall the red triangle and a console message which may have been REP. Also, CEL may have flashed on on during the event -- can't recall -- I was a bit stressed about the behavior on the up side of narrow hill with traffic behind and the un-expectedly surging bronco beneath me to note exactly what happened.

Then it just stopped near top of the hill, everything worked fine. After a brief level spot, I made it up another comparable big hill and down the other side to work. End of day, drove home no problems at all on a number of different level and slight uphill grades and traversing similar kinds of hills although on a different route.

Any thoughts on next troubleshooting steps on this (intermittent) one?