Ex­haust pres­sure sen­sor

Car Mechanics (UK) - - Diagnostics Doctor -

The EML in my 2009 Volk­swa­gen Pas­sat 2.0 CR TDI came on af­ter 93,000 miles. My Foxwell NT500 scan­ner – which I am not very good at us­ing! – is giv­ing the codes ‘001137 ex­haust pres­sure sen­sor 1 (G450) im­plau­si­ble sig­nal’ and ‘009299 DPF fil­ter dif­fer­en­tial pres­sure sen­sor im­plau­si­ble sig­nal’. The scan­ner gave the code info: ‘01137 Fault sta­tus 11100000; pri­or­ity 2; freq 1; pres­sure -82mbar and -77mbar’ and ‘09299 Fault sta­tus 11100000; pri­or­ity 2; freq 1; pres­sure -87mbar and -77mbar’.

I have cleared the codes and driven 30 miles so far with­out bring­ing on the EML again. I as­sume that it is the same sen­sor? If so, I sup­pose this could be a faulty sen­sor or prob­lems with hoses or wiring. Given that I have had the dif­fer­en­tial pres­sure sen­sor re­placed on a Peu­geot 307 2.0 at 100,000 miles, it would seem likely to be the same thing. How­ever, I un­der­stand it would need adap­ta­tion/cal­i­bra­tion once fit­ted, and to do this I need a chan­nel num­ber and value to code it. I know that two part num­bers were used, but mine is the later one – part no 076 906 051B.

Also, the DPF has 108ml of ash and it has been 530 kilo­me­tres since its last re­gen­er­a­tion. How much ash can the DPF hold be­fore it needs to be cleaned? Ian Hil­drew First, I should say that all ve­hi­cles with a DPF should be us­ing a low ash oil to ex­tend the life of the DPF. It should be noted that ash and soot are two dif­fer­ent prod­ucts. Soot will burn off from a DPF dur­ing re­gen­er­a­tion, whereas ash will not, as it is made up of inert in­or­ganic met­als and min­eral com­pounds from lu­bri­cants and the re­sult of en­gine wear. This will build up to a point where the DPF will be­come blocked. The re­gen­er­a­tion will con­tinue to take place but will not re­duce the back pres­sure. The max­i­mum oil ash vol­ume of the DPF should be around 380ml and, us­ing the rec­om­mended low ash oil or low SAPS (Sul­phated Ash, Phos­pho­rous, Sul­phur), it would be ex­pected that the en­gine should have covered nearly 400,000 miles be­fore this was achieved.

The ‘G450’ im­plau­si­ble sig­nal codes do in­di­cate a fault with the sen­sor, but it is also very likely that the prob­lem is in the wiring loom be­tween the sen­sor and the ECU. Pay par­tic­u­lar at­ten­tion to the loom where it in­ter­sects with other sets of wires just above the gear­box. It has of­ten been found that where the loom then con­nects to the ve­hi­cle body, the plas­tic in­su­la­tion trunk­ing can chafe through the wires in­ter­nally. If no faults are found with the wiring, then the sen­sor will most likely need re­plac­ing

Newspapers in English

Newspapers from UK

© PressReader. All rights reserved.