Intermittent power loss - turbo/brake sensor??

[paul chocks]

Hi,

I need some help with an intermittent power loss my 2014 D5 Auto is suffering from. Its got me and my mechanic stumped, and I thought I'd ask here before hopeful component changes.

About 3 weeks ago my wife told me that her car just started to slow down on the motorway. Applying pressure to the accelerator made no difference until finally the car lurched forward and throttle response was recovered. She slowed from 70 to 40 until any response occurred.

Since then, I have driven the car on my commute. Every now and again (probably once in 30 miles driven), I have the same, where the car doesn't respond to throttle response. When it happens, I can force the car to respond by changing down a gear or two, which seems to recover throttle response.

VIDA gives a few turbo related codes, with one 'red' one PO23600. However, VIDA also says this results in no symptoms.

Now, immediately before this problem happened the car had been repaired for a DSTC/ABS issue. Shortly after pulling away after start, the car would judder, try to stop and the above caution lights would illuminate. The car would then recover to normal driving and the car would report DSTC Service Required. This was diagnosed as a bad sensor on a rear wheel which was replaced and the cautions cleared. Since then we have been getting the symptoms listed in the first few paras. Even though we have turbo related VIDA codes, I'm thinking that the problem may still be related to an ABS type problem, even though there are no codes for that - it would be a strange coincidence if not.

Does anyone have any useful clues. My mechanic - ex Volvo tech - is reluctant to just change parts until we have a better idea of what it may be.

Thanks in advance.

[Croft]

I have a 2008 V70 with 185,000 miles and recently had issues with power loss. I was on a dual carriageway and exiting a roundabout when at around 3500rpm the car hesitated and then cut out. Thankfully I have manual transmission and was able to coast until I could restart the engine. No warning lights at all.

Continued cautiously and the car seemed fine, would rev past 3500 with no issues but did not seem to pull as it used to. It seemed to me that fuel starvation might be a cause as the filter had never been changed to my knowledge. So I changed the filter and using the car locally, it seemed Ok but not with all the low down torque I was used to.

Looking around, I noticed that the swirl arm link had become detached. Moving the swirl arm manually, it moved freely suggesting that it was in good health and not clogged as some posts refer. The plastic link arm was a very loose fit on the arm end, and clearly suffering from plastic fatigue as I snapped it. Making a temporary repair with some epoxy and cable ties, the car was much more responsive. So the disconnect was clearly part of the issue. A new arm from my local Volvo dealer was only £6 or so.

Feeling pleased with such an easy fix, I felt that the car was still occasionally slightly hesitant around 3500rpm but it was usable. I was then dismayed to discover on a recent long distance trip that the car had significant power loss after being restarted from warm. No problems from a cold start. Checked and swirl control link arm was all connected. Eventually the EML came on. Got back and checked codes. These pointed the MAP sensor being out of range. P2227 and P0069. Additional research on this forum and generally on the web also pointed to this.

Volvo dealer was able to get a new sensor for me (around £100). I know that you can get it (allegedly) cheaper, but my perspective is that for the equivalent cost of half tank of fuel, why risk it. Swapping it over was straightforward, although you can only get one arm into the space. The sensor is located on the intercooler pipe behind the passenger side bumper. I simply removed the air filter box and short feeder cowl, and then I could reach in with a T20 torx screwdriver. It’s just one screw and the connection. I had to remove the sensor first to allow me to reach in with both hands to disconnect it. Simple replacement, bonnet up to bonnet down was around 15mins. Cleared the codes and off for a test drive.

The car is transformed. It now seems really, really responsive. So....... I am thinking that this sensor has been giving poor readings for some time now as it was failing. As with all things gradual, it is difficult to notice. Possibly the bad readings had caused the swirl control arm to ‘over reach’ and become detached in the first issue.

Hope this adds to the body of knowledge and understanding on this forum.

[Cento16v]

Brake Pedal Switch?

If it thinks the pedal is being depressed the car may cut fuelling?

Data log it to see 👍

[zork]

PO23600 usually is the one of the two pressure sensors to blame as Croft says...A very common problem to these engines,data log while running the car arround should have figure it out if,or which one...Strange that your Volvo tech guy didnt figured it out...dont want to judge him, but maybe thats why he is an ex tech guy...

[rnchance]

Hi Did you ever get to the bottom of this? I have exactly the same symptoms but no DSTC issues.