Performance Down (like no turbo) so far tried...

Hi, the lamda light came on on my 850 tdi last week. It's like driving a car with no turbo / performance is way down Got the codes read and are as follows: 302 "Knock sensor fault" 304 "Speed signal faulty" 308 "Intake air temp sensor" So Far checked intercooler hoses above/below - none seem to be leaking(had that before) If you squeeze the hose and get someone to blip the throttle you can feel it pressurising Vacuum hoses - seem ok / I've replaced a few of these before Switched the MAF sensor with one sourced from an Audi 100 TDI (same Bosch part num) - made no difference. It's likely that this one has been sitting on a shelf for a few years. There seems to be vacuum getting to the EGR valve although you can't see if it is actually operating. (no rod on this type) I also pulled the air intake hose to the turbo off to make sure the blade on that side is running freely with no major play Any suggestions on what to try next? Could I have got a dodgy MAF sensor? Is there any way to test one? Any way of testing EGR??? I've seen on a recent post(outnumbered) about the vac pipes running to the Vac reservoir - I haven't checked those yet and will do so. Any other sensors worth checking / how do I test them I'm a novice when it comes to diagnostics but I'd like to have a crack at it fixing it first before throwing in the towel and going to a garage. Any help much appreciated

"Got the codes read and are as follows: 302 "Knock sensor fault" 304 "Speed signal faulty" 308 "Intake air temp sensor" Who read the codes and with what, these are not Volvo codes and to my knowledge there is no Knock Sensor on a diesel!

Engine: TDI: - Performance Down (like no turbo) so far trie 

Hi Chris - the codes were read using a Bosch KTS (650 model I think) diagnostic kit. I did this at my local technical college. The 850 tdi model was covered in the software.

From problems with my V70 (audi) diesel it would appear that you are on limp home mode. Our car would not pull the skin off a rice pudding until the codes were cleared using the computer program. Dont know what kit you are using but there was a section for code clearing on the garage equipment we used. Had to fix the MAF first of course otherwise it just came up error again.

Engine: TDI: - Performance Down (like no turbo) so far trie 

Hi - an update on my 850 tdi poor performance had it read using the portable volvo tool and the following codes came up 713 - injection timing value - signal too low 122 - air temperature signal 121 - air flow sensor 123 engine coolant temperature signal on clearing the codes only the 713 came back (still way down on power) I had the live data read and the injection angle is coming out at 23 degress - against a desired value of 4.7 degrees. This is way out and may explain the engine sounding lumpy although it starts no problems I checked both the inj pump belt and the timing belt and the belts seem in reasonable condition - I don't think either have jumped a tooth She's due new belts in another 10 k so I plan to get this done next Saturday by an experienced volvo mechanic who will set up the pump timing afterwards. I'll update on how it goes. fingers crossed!!

Code 713 is injection timing valve, signal faulty. This is an electrical problem either with the valve itself or the wiring The injection timing valve is part of the fuel injection pump, the first thing to do is check the connector from the pump to the wiring loom for a poor connection and the wiring for damage. If it turns out that the injection timing valve itself is faulty I think the only cure is to replace the fuel pump.

Update- Engine: TDI: - Performance Down (like no turbo) so f