**cross Posted on other forums**

Hi, I just bought a 2006 XC90 AWD V8 and as we drove it home (bought it in another state) the check engine light came on. My husband is horrible at gas caps & hadn't put it on properly, so we assumed it was only that & we would get it cleared when we got home. Well fast forward a week when I went to get the safety & emissions done and the codes were pulled - we had the gas cap, but also a P0430. I obviously wasn't going to pass emissions, so I called the local Volvo expert (our dealership is an hour away, but he is factory trained) and he pulled the codes, still the P0430 but we had a new one, P0193. We talked about options and how the cat code is hard to diagnosis exactly what the problem is, we decided to go with 2 new oxygen sensors and a fuel pressure sensor. 1500 + 100 for diagnosis later, and I was hoping we were good to go. Next morning, the CEL was back on. It was the weekend, so I did tons of research & had the code cleared numerous times, but always came back within 80 miles. I tried a cataclean treatment, a seafoam in the gas treatment. Monday morning I went to see if it would be ready to test before the light came back on and there were multiple engine misfire pending codes and the same P0430 pending code. The next day I decided to try for an emissions waiver and so I took it to jiffy lube to get a failed emissions test, as I turned the car on, it said "Low Battery" on the display, I pulled out and started to drive, all the sudden my CEL was flashing and the computer told me to
"Slow down or Shift Up" (can't remember exactly) I turned the car off immediately and let it sit, when I turned it back on, it drove fine as if nothing had happened. I took it back to the mechanic where he has been trying to figure out what is going on. He said he is pulling crazy amounts of codes from almost every module. Climate problems (we have the issue where the passenger side alternates blowing hot & cold air) and now he said there was a code for a transmission issue, torque converter control or something. WHAT SHOULD I DO??! Could a computer problem cause all of this? Please help!

 

Maybe next time buy a 1978 Dodge Aspen if you don't like the complexities of modern vehicles?

 

Cool response.

I've owned 7 different makes and models of cars in the last 16 years the oldest one being a '97 and have never had (seemingly) everything fail at once. Basically what I'm asking for is some ideas as to what could lead to these symptoms I'm describing.

 

Alexis,
I am new to the XC90, yet old to working with cars.
Your mechanic is pulling so many codes, from so many modules...
I would put five bucks on electrical.

It sounds dumb, yet check all the electrical basics.
Remove, clean, tighten the battery posts (clamps?).
Is the battery GOOD.
Known good, or "it starts" good?

Check the ground connection straps (chassis, engine block, etc etc).
Is the alternator all hooked up properly?

Let us know how it goes!

 

Alexis Adams Holt It would be good to have complete list of pulled codes.
"Slow down or Shift Up" usually means that there is a lot of misfires in the cylinders.
Misfire can be the culprit of cat codes. When the spark plugs were changed?
As for other electrical issues first make sure that battery is ok and alternator too.
It is better to take list of the codes using Vida+DICE (dealer equipment) and post them here for additional analysis.

 

Going to the dealer on Friday so I will ask for a print out. I will ask the mechanic if he's checked on the battery & alternator. I have no idea when the spark plugs would have been changed, I had just bought it 3 weeks ago. I asked the mechanic about spark plugs & he sort of blew me off & said he's pulled spark plugs out of v8s at 150k miles that look brand new. My car has 80,000 miles on it. So my guess is that he didn't look at those, but I'm not positive. Thanks for your response I'll update soon.

 

I'm glad you think that too! I am hoping that it's all explained by one problem rather than a lot of small (or big) problems. Someone obviously dumped it before it was sold so it scares me that this would seemingly be the second mechanic to give up on it (mine suggested I clear codes and trade it in). I'll come post after I go to the dealership on Friday.

 

Just got back from the dealership, they did not seem to find as much as the other mechanic did, they think the misfires & codes were more flukey due to a low battery at this point but see if it still happens. I do need a cat, the bid was 3200+tax but they said a muffler shop may be able to do it cheaper but not positive, any experience or guidance on this? He said spark plugs should have been replaced on it & that could also be a reason for the misfires.

 

If several modules are showing several faults then I would also suspect an electrical issue, most likely a loose power connection somewhere.

The flashing CEL indicates misfire that is serious enough to damage the catalyst. The fuel additives/cat cleaners may have caused it. You may have felt the engine running rough while the CEL was flashing.

 

Another update, I just put in gas & as I pulled out of the station it misfired again & gave me the slow down or shift up message again. I pulled over & called the dealership, the desk person went to ask the mechanic that worked on it, he said he has seen that with fuel pump problems. Any thoughts on that??

 

Saga continues, went to have the codes checked after the misfires, it was in all cylinders & there was also a code for the crankshaft position sensor P0336. Never seen this code before...

 

I've never owned an XC90 but I've bought a lot of used cars. First thing I'd say is where you buy the car is more important than what you buy. Evaluate the seller first before you evaluate the car. If you have any doubts at all about the seller or their story, move on.

If you haven't figured this out already, you bought a problem car. I'm going to offer some advice on process as if you don't take control here you will wind up spending a fortune.

First, you need to be able to pull the codes yourself so you're not at the mercy of the mechanic du jour. Buy an OBD2 code reader from Amazon. .

Pulling codes is easy. You connect the reader to the OBD2 port and turn on the ignition. That's it. When you have pulled the codes, start Googling. There are many Volvo resources on the web and you will almost always find something helpful. You will often find the exact solution to your specific problem as every vehicle has design flaws that manifest as common failures.

Don't lose hope and don't throw big dollars at your problems yet. Mechanics will bankrupt you swapping parts if you let them. For example, $1,500 for two O2 sensors and a fuel pressure sensor (which you probably didn't need) is outrageous.

Now get that OBD2 reader coming and then post up the codes. You will find that you will be able to troubleshoot and solve your codes one by one. Often, multiple codes are set by the same problem.

On the P0336 code, the ECM uses data from the crankshaft position sensor to detect misfires. The crankshaft position sensor is able to measure crankshaft acceleration after each ignition pulse and if there is a misfire the crankshaft position sensor sees the misfire as a lack of crankshaft acceleration. The fact that your code is for multiple misfires suggests that the problem is either with the crankshaft position sensor itself or is caused by something else.

Ten seconds of Googling took me here. Someone else with your code and your vehicle solved their problem by cleaning up three grounds on the frame under the hood on the driver side. that means removing the bolts, cleaning up any corrosion and also cleaning up the ground tabs then reinstalling the grounds with dielectric grease. Start with that. If you do in fact have a ground problem it can cause all sorts of flakiness.

On the P0430 code, which two O2 sensors - be specific - did your mechanic replace?

One more thought. Though I have no direct experience of this, it's sort of conventional wisdom here that Volvos are sensitive to low battery voltage and can do strange things if the battery is in poor condition. If you have a conventional flooded lead-acid battery, have someone check the battery electrolyte and top off with DISTILLED water if necessary. Then get the battery checked and load tested.

 

So the plugs were not replaced? They are due at 75k. Whoever told you they can make it to 150k is an idiot.

 

Yup. I missed that. Do the basic maintenance before you start looking for more exotic problems.

 

I've never owned an XC90 but I've bought a lot of used cars. First thing I'd say is where you buy the car is more important than what you buy. Evaluate the seller first before you evaluate the car. If you have any doubts at all about the seller or their story, move on.

This is why I am so upset, I DID research the dealership before I bought the car, they have an A+ rating with the BBB, they have 60+ 5 star ratings on cars.com (where I found the car) and have been in business since 1975. They pride themselves on their referral business.

If you haven't figured this out already, you bought a problem car. I'm going to offer some advice on process as if you don't take control here you will wind up spending a fortune.

First, you need to be able to pull the codes yourself so you're not at the mercy of the mechanic du jour. Buy an OBD2 code reader from Amazon.

This one should do fine

This one should do fine

.

I have been using auto part stores to pull codes & considered buying a reader, but my husband didn't mind using the free service.

Pulling codes is easy. You connect the reader to the OBD2 port and turn on the ignition. That's it. When you have pulled the codes, start Googling. There are many Volvo resources on the web and you will almost always find something helpful. You will often find the exact solution to your specific problem as every vehicle has design flaws that manifest as common failures.

I have spent HOURS, so so many hours googling codes - I have found a lot of things that have seemed helpful, but I don't know enough about cars to implement them, so the idea was to have information to take to the mechanics I'm dealing with. For example, I found a post about a bulletin regarding a heater problem needing an software update & probably (hopefully) saved myself some money at the dealership today by telling them about it.

Don't lose hope and don't throw big dollars at your problems yet. Mechanics will bankrupt you swapping parts if you let them. For example, $1,500 for two O2 sensors and a fuel pressure sensor (which you probably didn't need) is outrageous.

Now get that OBD2 reader coming and then post up the codes. You will find that you will be able to troubleshoot and solve your codes one by one. Often, multiple codes are set by the same problem.

On the P0336 code, the ECM uses data from the crankshaft position sensor to detect misfires. The crankshaft position sensor is able to measure crankshaft acceleration after each ignition pulse and if there is a misfire the crankshaft position sensor sees the misfire as a lack of crankshaft acceleration. The fact that your code is for multiple misfires suggests that the problem is either with the crankshaft position sensor itself or is caused by something else.

Ten seconds of Googling took me here. Someone else with your code and your vehicle solved their problem by cleaning up three grounds on the frame under the hood on the driver side. that means removing the bolts, cleaning up any corrosion and also cleaning up the ground tabs then reinstalling the grounds with dielectric grease. Start with that. If you do in fact have a ground problem it can cause all sorts of flakiness.

Yes, I saw this same post - like I mentioned, I just don't know enough about cars to feel confident doing these things. I have been waiting for the weekend to have my husband try to look into it too.

On the P0430 code, which two O2 sensors - be specific - did your mechanic replace?

He changed the front & rear sensors on bank 2. I decided to do some digging when I started having problems, and found the number for a muffler shop that was on the carfax - they had replaced all 4 sensors in June (a mechanic would be able to tell that right?!?!) and so my mechanic said he'd give me the part cost for O2 sensors ($400+) in work when I had the misfires. He basically did some "diagnostics" and it used the shop time & he ended up with no answers.

One more thought. Though I have no direct experience of this, it's sort of conventional wisdom here that Volvos are sensitive to low battery voltage and can do strange things if the battery is in poor condition. If you have a conventional flooded lead-acid battery, have someone check the battery electrolyte and top off with DISTILLED water if necessary. Then get the battery checked and load tested.

I have read a lot about this, but just assumed that 2 volvo mechanics (both worked at the dealership, one past, one current) would have realized if there was a low battery or voltage problem. I will check this out this weekend as well.

I genuinely appreciate your post & your advice, thank you.

 

I'm not sure why he completely disregarded my requests and questions about the plugs. I'm taking it on Monday to have them checked out by the mechanic at my uncles auto body shop. I'd been trying to use volvo trained mechanics but it has proved to not be helpful so far.

 

That is a very good mechanic to respond like that w/no more information given .

 

So I'm just going to spout what the test results were from the guy at Napa, and hopefully it makes sense.

Starter Test:
Load off: 14.49V
Load on: 14.36V
Diode Ripple
Ripple Detected
0.60 High

Battery Test:
Rated: 600CCA
Measured: 283CCA
State of Health: 47%
State of Charge 86%

I bought a battery, putting it in currently, what is the next step at that point? Clear the check engine light and then just drive and see what pops back up?

PS I've posted this on 3 forums and almost all responses were to change the battery or about the alternator, I was waiting for my husband to be home and be able to do it, but why in the world wouldn't these mechanics have checked this out?

 

These are Volvo dealerships you've been taking it to? Or a guy with a scanner who worked at a dealer once?

 

I've taken it to both, the mechanic in my first post is a guy who is factory trained but has an independent shop now. On Friday I took it to the dealership service center so my updates are from when I went to them.