Advice needed, possible O2 sensor??

[higgy]

Hi,
My wife's D5 (185) went in to limp mode last week. I changed fuel filter and went to local volvo specialist to get the codes read & limp mode reset. There were various codes ECM-28 D0, E0, 10, B0 all heated oxygen sensor (HO2S)
Also ECM-25 20, 30, 90, A0, fuel system too low pressure.
It was fine for a couple of days until it happened again. I ordered VIDA so I could troubleshoot myself, but haven't got an appropriate laptop yet.
I then remembered when I brought the car (Feb this year) the previous owner gave me the Volvo assistance details.
So I called them yesterday and someone came out to me. He did a scan and said that the DPF is blocked so he ran the clearing programme. After this he said it should now be fine. Took the car for a quick spin, felt brilliant.
My wife goes out this morning and it's happened again, limp mode!
Not sure where to go with this as if I call volvo assistance again surely they will tow the car to the dealer, (don't want this yet as can't afford a dealer repair bill!)
Has anyone got any advise in the codes? I'm thinking if I change the 02 sensor and see if it helps? Would a duff 02 sensor cause the fuel pressure messages?
I had a quick look at the wiring this morning and looks ok.
Any help advise greatly appreciated.

Cheers

Matt

[higgy]

Just has a spare 10 mins so I have removed the O2 sensor. I was going to test it with a blow lamp but there are 6 wires and I'm unsure which one to test with the multimeter.
Does anyone know which wire it is?

[Ettienne]

Why didn't you just use live data? No need to mess about

[Ettienne]

The egr valve blocks up stupidly on these as well.

[Ettienne]

I doubt the lambda will give more than a warning, I've never had one cause limp mode, other than the dash warning.

There is some debate but there meant to be service items at 100k.

[higgy]

I've not got my vida up and running yet as I am still trying to acquire a suitable laptop.
Will check the egr valve but was thinking due to the fault codes the 02 sensor seemed likely. Had a look though the service history and can't see mention of one having been replaced. Mileage is now 142k

[Ettienne]

Not too expensive to replace, a guy in here just bought one for £35 ish on eBay

[oblark]

I brought a genuine bosch one off of ebay for £74

[higgy]

Didn't test it in the end, couldn't work out which wires were which!
If I hold in msg button and trip reset I get two codes,
042 = h02s heater control circuit (bank 1 sensor 3)
137 = O2 sensor circuit low voltage (bank 1 sensor 2)
So I thought it was the first sensor which has the heating on it but according to this it's the second sensor which is the Cat sensor?
Can any one shed some light?
Will have a look on E-bay and maybe buy both?
Cheers