A friend has a signum1.9cdti which keeps going into limp mode. He has had it read but no codes showning. He was told it was the particulate filter so he changed that no difference. I was just wondering if anybody had any ideas.

Can you do the pedal trick on a diesel 

partical filter ££££££  ouch !!  someone guessing ??

He just bought a pattern part £340 vx want £800+ when he took the old one off nothing inside empty

What type of oven cleaner and how do you rinse/dry afterwards

What type of oven cleaner and how do you rinse/dry afterwards

Don't know about oven cleaner but used some well diluted caustic soda on one myself & it worked a treat. Gave it a good rinse out afterwords. Most importantly PDF must be regenerated when refitted. This not only completely cleans out remaining soot frim DPF it also resets the counter in the engine ECU that works out the soot loading in same.
Two things though.1- DPF regeneration willl not happen if there is any fault picked up in engine ECU. (Split pipe from front of DPF to pressure sensor on bulkhead being one that comes to mind). Any faults in engine Ecu must be eliminated before it will proceed. 2- DPF temp gets up to 650 degrees when regenerating so only do it in a wide open space on concrete. Also you do need diagnostic equipment to trigger a regen.

Usually the problem with this engine is a failed Egr valve that stuffs the DPF with soot after 100 miles driving. On earlier cars without DPF the EGR would just cause power loss & hard starting.

Morning all, just had a call from my mate he said he has just tried the pedal trick and nothing happened the light with the car/spanner just stayed on. He said he did the following foot on brake foot on gas turned on to position 2.
Any ideas welcome. He has had the car plugged in with a auto electrian while the car was in limp mode but it showed nothing would this be because the reader is no good? He has stated that he has cleaned the  egr as well..