U0301, no power, 1.6d

[Jamz3k]

Folks, I’ve got a 2010 V50 1.6d with 154,000miles which gets to 40mph and then struggles, getting to 70mph is doable but it’s hard going and it will lose speed on a hill.

The only fault code is U0301 which I can’t find much info on.
The car revs freely and starts on the button.

What’s your thoughts? I’m thinking DPF as its due replacement but as there is no fault codes(apart from u0301)or warning lights, I’m weary of doing this and it not solving the problem as the cars now at a value/condition that may not make it worth throwing parts at.

[Moomoo]

Change the fuel filter first. I had loads of similar grief , spent loads, it was the fuel filter.

Do that first!👍

[Jamz3k]

I’ve got one to fit into it just incase. I recently (3months ago) fitted one and they are blooming expensive but I’ll give that a go next week.

What I did find today was a crumbled/blocked pipe from the DPF into a valve at the battery box. I replaced the pipe with a bit of fuel line and the car ran worse until the pipe burst off the valve and the cars drivability’s improved greatly but still not perfect.

[wynnj]

Originally Posted by Jamz3k

I’ve got one to fit into it just incase. I recently (3months ago) fitted one and they are blooming expensive but I’ll give that a go next week.

What I did find today was a crumbled/blocked pipe from the DPF into a valve at the battery box. I replaced the pipe with a bit of fuel line and the car ran worse until the pipe burst off the valve and the cars drivability’s improved greatly but still not perfect.

If you've already changed the filter and bled it thoroughly, changing it again is unlikely to improve matters. However, the fact that changing things associated with the 'valve' by the battery could well indicate a failed 'valve' and or blocked dpf. It's a differential pressure sensor and there should be two tubes going to it from upstream and downstream of the DPF. If it fails it might never trigger a DPF regen or, as in my case, it might permanently try to trigger a regen until the glow plugs burn out. You'll find my write up in the archive. I bought a new sensor off ebay for less than £20. If you go down that investigation route and can't find a replacement send me a PM as I have one which I'm happy to sell for what I paid as I bought a spare after fixing the problem but am now about to sell the car as my wife no longer uses it.
Also, while fuel line may work in diagnosing the problem I've read on here that you're strongly advised not to use it permanently because of the very high temperatures around the DPF. It's possible that someone has used fuel line previously which has now deteriorated contributing to the problem.

P.S. These links might help with decoding your DTC
https://www.dtcdecode.com/Volvo/OBD-...ross-Reference
https://www.dtcdecode.com/Volvo

[Jamz3k]

Cheers wynnj, I’ve ordered replacement pipes,I’ll try them first, then the pressure sensor and if that fails, I’m probably set it on fire.

Not looking forward to fueling my m135i into work everyday until this is fixed lol

[Jamz3k]

Folks I could do with some guidance with with car.

Since I last posted I've done the following.
-Replaced the pipes to DPF Pressure sensor.
-Removed and cleaned out the DPF with Wynns DPF cleaner
-Replaced 2 injectors (diesel at No.2 injector, used a leakoff tester and changed
No.1 for good measure)
-Cleaned EGR Valve out (it was fine tbh)
-Replaced Fuel Filter

Once I refitted the DPF back into the car, road tested it and I then started to get a MAF sensor low signal fault P1103 and an ECM fault 7700. I checked and found the wiring damaged/rubbed through. so I repaired the wiring and road tested, no difference. I then replaced the MAF sensor and it ran like a real bag of spanners, surging etc etc but with the same fault codes. when I refitted the old MAF sensor, I was back to square one and the fault code is still active.

Currently the car drivers fine under 40mph, maybe a bit down on power but once you try to go above 40mph it struggles and it will cannot make it up a hill at 70mph in 5th gear, the speed with drop back to around 50mph.

What should I do next? As this car is really starting to test my patience.

[Clan]

Originally Posted by Jamz3k

Folks I could do with some guidance with with car.

Since I last posted I've done the following.
-Replaced the pipes to DPF Pressure sensor.
-Removed and cleaned out the DPF with Wynns DPF cleaner
-Replaced 2 injectors (diesel at No.2 injector, used a leakoff tester and changed
No.1 for good measure)
-Cleaned EGR Valve out (it was fine tbh)
-Replaced Fuel Filter

Once I refitted the DPF back into the car, road tested it and I then started to get a MAF sensor low signal fault P1103 and an ECM fault 7700. I checked and found the wiring damaged/rubbed through. so I repaired the wiring and road tested, no difference. I then replaced the MAF sensor and it ran like a real bag of spanners, surging etc etc but with the same fault codes. when I refitted the old MAF sensor, I was back to square one and the fault code is still active.

Currently the car drivers fine under 40mph, maybe a bit down on power but once you try to go above 40mph it struggles and it will cannot make it up a hill at 70mph in 5th gear, the speed with drop back to around 50mph.

What should I do next? As this car is really starting to test my patience.

I assume this IS the 1.6D ( 4 valve engine) rather than the D2 ( 2 valve engine)

In which case the DPF MUST be changed every 72000 miles and the Eyloys additive tank filled and reset.. I note you have not mentioned this. Also there may be a fault code suggesting "Incorrect Engine Software" It is important that you have the latest software ..

[Jamz3k]

the DPF has been cleaned out as above. Reading the live data, it wasn't blocked before cleaning it out and its certainly not blocked now but I thought it was worth cleaning out. The Eolys system seems to be throwing a bit of a fit though, its showing as warning for being empty but when I run a level test, its coming up as full.

I'd go straight to filling the Eolys tank and priming but the lack of emissions fault codes, the 7700 & U301 codes and the state of my wiring loom (ie it's been removed from its mounts and cable tied back in place) makes me think that someone has been at the ECU and had the DPF/emissions kit mapped out of it....badly.

I did get rid of the MAF fault by replacing the Boost Control Valve for the turbo, doesn't run any better but oddly it the fault hasn't appeared after 100miles of driving.

At no stage has the vehicle been in limp mode or Rev's capped, there has been no DPF blockage warnings etc and the turbo feels fine.

[P4]

U0301 is a communication error between the ECM and the PCM. Usually one of them is faulty but, considering the state of the wiring harness, I would suggest something as simple as a broken wire or bad connection somewhere in that loom.

[Jamz3k]

Originally Posted by P4

U0301 is a communication error between the ECM and the PCM. Usually one of them is faulty but, considering the state of the wiring harness, I would suggest something as simple as a broken wire or bad connection somewhere in that loom.

I think you're right! I've begrudgely lost so much of my time off working on this car lately, I think if I spent this weekend poking around with it, I'll end up single!