Is this "limp mode"? What's going on?

Volvosmakememad16 · Post by **Volvosmakememad16** » 12 Apr 2016, 04:01

I apologize for the lenghty post, but unfortunately owning a Volvo seems to come with some lenghty problems.

So my boyfriend's XC90 is having some strange issues. Last month we
brought it to the dealership to be fixed, because one day the engine light came on and read "reduced engine performance" as well as "engine service required". We tried driving it down the road, and found it would only go about 15 mph, and about 5 mph when going uphill, causing us to believe it was in "limp mode". During this, the lights would flicker and the car would sputter as if it was losing power.

After a few hours we turned on the car again, and though the engine light was still on, it no longer said "reduced engine performance" and we were able to drive at a normal speed with no malfunction in the lights and no sputtering. We made the drive to the dealership. The ABS light had been on for a while, and the service center said the ABS sensor would need to be replaced and would likely stop tripping the limp mode once replaced. We were super skeptical that the ABS could possibly be causing the engine to have problems, but we didn't know what else it could be. They said there was a "throttle valve" code as well, but it was inactive and not likely to be causing the issue. We paid about $400 for the ABS to be fixed, and drove away with no further problems until about a month down the road which leads us to now.

We turned on the Volvo yesterday and found ourselves in the same predicament of the engine light on, "reduced engine performance", "engine service required", lights flickering, sputtering, and limping. We limped it a couple miles to a parking lot. After turning it off for a few minutes and turning it back on, everything seemed fine and back to normal. We went about the day with no issues.

One day later, today, start the Volvo, and lo and behold! - repeat of yesterday morning. Only the problem hasn't stopped or returned to normal yet.

One thing I should mention, is the drainage system for water in the roof from the sunroof/door frames is super faulty. If it rains, the water never drains fast enough or completely, and has subsequently fried a bunch of the electrical junk under the floor of the vehicle. The radio hasn't worked for over a year due to this damage. It appears that each time we have seen these engine issues and limp mode, it has been after moderate/heavy rain. We try to cover the Volvo with a tarp over the sunroof when it is raining, but of course isn't always possible.

Why is this happening? Is the rain the cause? Would a throttle valve cause this? Transmission? At a complete loss here. Contacted the dealership and they obviously said they'd need to see it at the service center again. Not too excited to dump more money into a vehicle that has caused nothing but problems.

weespoon · Post by **weespoon** » 27 May 2016, 18:37

Yes this does sound like electrical issues related to the sunroof drain as you suspect.

The sunroof drain you can fix yourself. I would recommend simply hose clamping clear vinyl tubing near bottom of tube and running that outside instead of futzing with the part that gets clogged at the bottom. I trimmed and cleaned this clogged part on one side and installed the vinyl tube on the other. The side with the clear vinyl tube drains much faster. Also once drains are repaired you can pour hot water (maybe from a flower pot) slowly down them from above to help clear them more.

Regarding standing water, a wet vac (like the vac at the car wash) is great.
Push with considerable pressure on floor carpets front and back.
I than ran a dehumidifier in the closed car for a couple of days to dry it out the rest of the way.

Water in the passenger compartment can definitely effect the "throttle position sensor", which is electrical and inside the passenger compartment.
I am not saying that this is why your car is in limp mode, but it could be related.

agusta · Post by **agusta** » 18 Jul 2016, 14:37

Sounds like your alternator is going out. Happened to my vehicle and the issues was resolved after replacing the alternator.

Post by **FLXC90** » 25 Jul 2016, 15:33

Which sensor did they replace in your ABS-was it the Yaw Sensor? This sits under the floor and is susceptible to clogged drains. It will affect your ABS, disable your traction control and all wheel drive, if you have it. it will show up as ABS service required. Search the database for the repair to the sunroof drain tubes, it should be a one time fix for you. Where do you park, in a driveway or on the street? Can you park with the nose downhill. that would be better than uphill.

Adnan Alnfaiai · Post by **Adnan Alnfaiai** » 16 Oct 2016, 15:04

I am suffering from the same problem of reduced engine performance and I do not have sunroof in my car .

arfstrom · Post by **arfstrom** » 17 Oct 2016, 06:10

So, your problem is going to be different, because you don't have sunroof drains. that leaves AC drains, and maybe the drain under the hood. Youtube has videos on those repairs. PS, you didn't give your vehicle info, so its hard to image what commonalities you might have. my XS90 05 2.5T, had the same issues, but it was caused by my timing belt, and the VVR not being set right. at least that what the mechanic told me. (VVR or something like that), and previously my sunroof did leak, so I have done the replacement as suggested here. so I know there are two other liquid drains that go though the passenger compartment. Good luck