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So I bought this Lexus is 220d from a car dealer 50 miles away, just as I got a few roads away from home I lost my acceleration. I was pulling out from a junction and it suddenly had nothing to give. Here is the fun part... I bought the car with the VSC and engine management light already on. My first thought was that it was going to be a simple DPF issue or something simple. The car did still have power even with the VSC light on and it still runs fine now but no acceleration.

DTC from scanner: P1426, P2002 (Particulate Trap Efficiency Below Threshold (Bank1)) and P2047 (Reductant Injector Circuit / Open (Bank 1 Unit 1)).

 

What I have done to find and fix the problem.

General inspection revealed sensor from back of the engine (I think 5th injector sensor P2047) was unplugged and so was another in the DPF (I think temp sensor P1426 code). After plugging them both in the codes went away.

For P2002 I took the car on a very long run after using a DPF cleaner and fuel additive and had no effect. Decided to try remove the DPF from the vehicle to have a look but to my surprise before I removed it completely I could see light coming from the other end. I think the people before me obviously removed it unless it has been broken up and inside of the convertor itself which I think would be unlikely as I would have seen some sort of broken material surely?

One of the differential pressure sensor tubes that come from the DPF is blocked, I could not unblock this with a tyre compressor so I used a T connector to join the two and then used another T connector to go straight into the pressure sensor. I was worried about the sensor getting too much pressure so I decided to put a couple breather holes in the tube so the pressure wouldn’t build up even close to 14psi. This has cured my VSC light.

I have done tests with the differential pressure sensor and I think it seems to be in good working order, unplugged the signal reads 4.8v, plugged in with power its 0.8v and when the car is running it will fluxuate around 0.8v.

It does seem like its missing the power from the turbo as if I had a leak between turbo and manifold. I have looked for vacuum leaks but it’s been hard finding any problems.

I have inspected the turbo actuator (wastegate) and it seems to move and do its job.

Alternator is charging and Battery is good health.

Glow plugs have good resistance and volts going to them.

Put paper against the exhaust to see good pressure and no suction from exhaust valves.

EGR is clean and good condition the valve moves freely. While inspecting the EGR I could see a fair bit of carbon maybe oil build up on the air intake manifold.

Vacuum pressure regulator seems to be working fine in regards to resistance etc. but not sure if its diverting the air to the filter when volts are going to it. I done the test while it was still on the vehicle and could read it had 12v supply while plugged in but when I blew on the hose I was still coming out of the other hose not filter, sure it would provide a DTC if it was faulty.

 

I spoke with someone that done remapping and he said if I deleted the files from the ECU then I wouldn’t have the problem with the DPF anymore assuming all the sensors and everything was in working order, he told me he couldn’t find any problems. I paid the guy £250 to come out he remapped my car and it had no effect...

 

Its driving me crazy I need to get this fixed.

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Could be dirty or faulty throttle body 1St could try to clean it. When I bought my is220d in 2013 from an independent dealer in Preston told me they cleaned it.

It's just a suggestion but worth a try 

Obviously dealer knew problems that y sold it cheap. Good luck 

 

 

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Sounds like a lot of different people have tried and failed to sort this car and you are now in a position where you have no idea what has been done and need to throw money at it with no guarantees. ( Why did you pay the "chip tuner" £250.00 for not doing the job he said he could do especially when if I remember Lexus ECUs cannot go reflashed).

The only thing you haven't mentioned is the boost pressure sensor which may be faulty hence the lack of turbo input.

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I will have a look at the throttle body when I get time. What does lexus call the boost pressure sensor, I had a look at the vacuum pressure regulator and vacuum switch thats on the top of the engine but they seem to be working fine.

Does anyone know what the symptoms would be if the filter on the regulating valve isnt opening. I tried to do the test below while the sensor was on the vehicle it was reading 12v but not allowing air to divert to the filter.

 

 

pressure sensor.png

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Solved! Started feeling around under the throttle body and found a hose detached from what I think is the turbo pressure sensor. I think steve2006 had the answer, I just had a probem finding the sensor location.

 

Car pulls like a train, I am sooo happy. Thanks guys for all your input.

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Yeah its strange and now worth every penny, I think the dealer didn't know the problem and unplugged sensors until he had a temp fix, I really have no idea. Thanks again ahmrdali your suggestion with the throttle body actually had me over that side of the car. :D

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