XC60 lack of response to accelerator

[Clan]

Originally Posted by an2rey

Looks like I am having the same DPF temperature sensor issue or possibly something similar. The car lacks power usually on 1200-1500 revs when coasting, engine is labouring and computer suggesting to change down a gear, mine is manual. Dealer had a scan performed, although, no stored codes, all clear. They took it for a test drive and identified that the car is thinking that exhaust temperature is constantly at 600 degrees rather then normal 200-300 degrees. Unable to find solution, therefore, sent tech report to Volvo technical department. Still waiting for the outcome.
Wondering whether somebody had a similar issues and can suggest what has been done to rectify the problem. My car is MY12 2.0 d3 variant.

600 C is the exact temperature when regeneration is taking place , maybe they caught it regenerating at that point in time .. They should have kept driving to see the soot mass reduce and then temp drop back to 200C after regeneration .. They could be up the wrong garden path .. if it is continuously at 600C though they ought to cnange the sensor. it wont give a fault code as 600C is still within the normal operating range ..

[an2rey]

Originally Posted by Clan

600 C is the exact temperature when regeneration is taking place , maybe they caught it regenerating at that point in time .. They should have kept driving to see the soot mass reduce and then temp drop back to 200C after regeneration .. They could be up the wrong garden path .. if it is continuously at 600C though they ought to cnange the sensor. it wont give a fault code as 600C is still within the normal operating range ..

Appreciate your suggestion Clan, although, regeneration was not happenning at that moment. By the looks the reading of 600 C was constant for the whole test drive, started from cold engine. Soot mass was showing 30% in the DPF, they had to do the forced regen and test it again. Same reading of 600 C was produced. The dealer said that they never dealt with such issue before.

[Clan]

Originally Posted by an2rey

Appreciate your suggestion Clan, although, regeneration was not happenning at that moment. By the looks the reading of 600 C was constant for the whole test drive, started from cold engine. Soot mass was showing 30% in the DPF, they had to do the forced regen and test it again. Same reading of 600 C was produced. The dealer said that they never dealt with such issue before.

when the temp sensor fails it is usualy open circuit which shows 1040 C when read out ..

[an2rey]

I see, that is probably why the dealer was unable to pin point the problem, as the temperature sensor is working correctly according to their tester. Could the DPF temp sensor giving the reading of a constant 600C if it was failing or some other component is responsible for such process?

[Clan]

Originally Posted by an2rey

I see, that is probably why the dealer was unable to pin point the problem, as the temperature sensor is working correctly according to their tester. Could the DPF temp sensor giving the reading of a constant 600C if it was failing or some other component is responsible for such process?

The sensor is simple it changes it's resistance with temperature so easy to test with a simple voltmeter .. it is very fast to respond, just revving the engine sees a change .. if it is stuck at 600 C i would see what happens if the sensor is unplugged , if the car and wiring to sensor is ok then there will be a reading of 1040 C ..
If it is still stuck at 600 C then look to crushed sensor wires or a faulty ECM ( very unlikely ) ..

[an2rey]

Originally Posted by Clan

The sensor is simple it changes it's resistance with temperature so easy to test with a simple voltmeter .. it is very fast to respond, just revving the engine sees a change .. if it is stuck at 600 C i would see what happens if the sensor is unplugged , if the car and wiring to sensor is ok then there will be a reading of 1040 C ..
If it is still stuck at 600 C then look to crushed sensor wires or a faulty ECM ( very unlikely ) ..

Clan, thank you very much for your input, really helpful. It is all sounding obvious and not to complicated to trace to see what exactly is failed or failing. Unfortunately, the dealer is having a bit of a hard time in tracing the issue. The car was back to the workshop twice since I have noticed the drop in power, and on both occasions I have been told that no fault codes stored, therefore it is absolutely fine. I have noticed the loss of power immediately, although, it is not that huge, only when the engine in mid range revs in 3rd and 4th gear, car just would not pick up speed as fast as before as a result it is telling me to down shift to a lower gear. Consumption has dropped as well, the ECU is thinking that DPF is regenerating, but it is not. I hope that Volvo's technical department can guide the dealer on how to find and rectify the issue. Let's see what the next week will bring, as it is already four working days since the report was sent.

[an2rey]

Clan, I would really appreciate your view on the following please.
The dealer has been in touch today with the update from Volvo Technical team. Apparently they suspect that the car has been missfulled at some point as a result the DPF has been permanently damaged. There are two options to try for the dealer: 1) specific update for the DPF 2) replace the DPF unit. Also the dealer has mentioned that when they have examined the DPF a small hairline crack has been found on the body of the unit (they haven't told that to me before). They assume that the crack is a result of DPF overheating and the unit might be loosing the temperature.
I have agreed for them to apply the update to see if it will put right the operation of DPF. If the update will not help that will be a new DPF (£1K+...?), I have some reservations about that.
What I can't understand is why there are no related error codes detected, surely if the DPF body is damaged and the unit is constantly running with the loss of pressure and temperature the ECU would detect that.
Meanwhile, the car is running and the DPF regeneration process is kicking in according to the computer, Emission Management message does appear and goes away after 20 min during the motorway driving. It is just not the same car, the power loss is evident.

[Clan]

Originally Posted by an2rey

Clan, I would really appreciate your view on the following please.
The dealer has been in touch today with the update from Volvo Technical team. Apparently they suspect that the car has been missfulled at some point as a result the DPF has been permanently damaged. There are two options to try for the dealer: 1) specific update for the DPF 2) replace the DPF unit. Also the dealer has mentioned that when they have examined the DPF a small hairline crack has been found on the body of the unit (they haven't told that to me before). They assume that the crack is a result of DPF overheating and the unit might be loosing the temperature.
I have agreed for them to apply the update to see if it will put right the operation of DPF. If the update will not help that will be a new DPF (£1K+...?), I have some reservations about that.
What I can't understand is why there are no related error codes detected, surely if the DPF body is damaged and the unit is constantly running with the loss of pressure and temperature the ECU would detect that.
Meanwhile, the car is running and the DPF regeneration process is kicking in according to the computer, Emission Management message does appear and goes away after 20 min during the motorway driving. It is just not the same car, the power loss is evident.

It is very difficult to make an opinion without all the facts. Assuming by damaged they mean "Blocked" or "restricted " this can be determined by the Particle filter Pressure sensor it will be high all the time .. I assume they will have monitored this on a road test .
The constant 600C temperature sensor reading seems to have gone quiet?

[an2rey]

Thank you! I assume that the dealer's report stated that the exhaust temperature is staying constantly on 600C, so the Tech department taken that into consideration suggesting the next plan of action. By "Damaged" I understood cracked, as mentioned above. I have asked whether it would not be better to change the related sensors first to see any changes in the readout reports. Obviously, changing the DPF is an easiest option, but definitely not the cheapest one for me.

[an2rey]

This issue is probably linked to the recent fuel contamination that was identified and has resulted in replacing all the injectors, electric fuel pump and fuel filter. It is unlikely that the cause was a wrong fuel (petrol), most probably it was contaminated diesel, as I have done 300 miles after filling up. There symptoms were difficulty on the start up, longer cranking and then the car just died and was recovered to the dealer.
The dealer has assured me that all the above components have been replaced and the car is back to normal, although, as mentioned before, the power loss is evident and I have to take the car back to them for further tests.
It is unclear to me why after such a major repair the car was not tested by the dealer to spot the issue with the DPF temperature and engine performance. All this has taken already some much time and money and I am beginning to lose hope.