Bosch VP44 Injection Pump Failure

It must be 3 weeks now since my beloved 2.5 V6 TDi Passat brokedown on me. Actually, that’s not entirely correct. The injection pump broke down on me, the Passat just happened to be cursed with the not so popular Bosch VP44 Injection pump.

My car was running great, freshly serviced by myself, I had no complaints – smooth and effortless, it was business as usual. Then, at the drop of a hat, it was crippled. The power rapidly faded away to nothing. It didn’t even have the guts to top 5mph.

“That’s it” I said. “The Passat is dead!”. Well, I was pretty much correct. The injection pump had pressurised its last atom of fuel before packing up for an extended holiday.

The gear indicator which usually displays the currently selected gear lit up red and the gearbox started shifting really violently. Initially I thought this could be a gearbox fault, but I later discovered this is simply a side effect of the car entering “limp mode”.

The car made quite a lot of smoke and the engine also sounded a lot more rough than usual. I noticed air in the fuel line too. A quick scan with Vagcom revealed 00550 – Start of Injection Regulation – Control Difference – Intermittent (also known as error code p1248).

I was genuinely hoping for a straightforward repair of the pump, but the reality was I needed a whole new one. I found a guy who really knew his stuff when it came to Bosch VP44 pumps, his name was Peter over at King’s Lynn Auto Diagnostics. He offered a prompt testing service for £70 and discovered the body (housing) of my pump was worn beyond repair, causing loss of fuel pressure. Wear in the pump housing means the pump is pretty much a write-off.

dieselbombers.com describes a similar problem:

The housings on the VP44 wear out due to low fuel pressure from weak lift pumps causing the diaphragm in the front of the VP44 pump to rupture. This causes the steel timing piston to vibrate in the aluminum bore of the housing and the result in a short time is the housing wears to the point that fuel bypasses the piston and full advance cannot be accomplished

Peter managed to source me a replacement pump, although he made sure I was sitting down before telling me the price, because it came in at an eye watering £762. He thought the damage to the housing was probably due to mileage more than anything.

I must admit, that was almost enough for me to seriously consider writing the car off. It has 180,000 on the clock and market value of the car is probably not more than £2000. But anyway, I decided I needed my car repaired. The exact model of the pump was 0470 506 002 – These seem rare and consequently expensive.
I’m still waiting for the pump to arrive (should be early next week). Peter assured me the new pump would be “virginised” so that it didn’t need to be coded to the car (watch out of this if you get one from a scrap heap)
It took the local garage about 3-4 hours to remove the pump, which just happened to be on a separate belt on the V6 TDI, so the cambelt did not have to be removed.

So the grand total for the pump failure comes in at about £1152 including fitting. I can only conclude this article by saying that under no circumstance buy a car with a Bosch VP44 injection pump, although if you’re reading this, the chances are it’s too late, you already did. Just take a quick look on the internet and there are pages and pages of people with similar problems. Good luck, you’ll need it.

6 thoughts on “Bosch VP44 Injection Pump Failure”

  1. I’m in total agreement about buying a 2nd hand car with a VP-44 fitted, had I known this before I would not have the car which has been sitting since May due to a fraudulent vendor of “Bosch overhauled’ pumps in Germany!

  2. Anyone buying a Diesel car with around 130,000 miles having one of these pumps should either not, otherwise be prepared to fork out a fortune. This is con by the car makers with the intention that you will scrap the car.

  3. mine done 88 thou and just stopped dead no misfiring lack of power nothing just like i turned off the ignition still havent got it running tried towing it pulled off injector pipe diesel coming through but without any pressure behind it totally fxxxked

  4. I had only bought my 8 year old Audi A4 TDi V6 3 weeks before the diesel pump went. I’m not so sure mileage is the key here; mine had only done 49,000 miles when it expired!

  5. Im having hassle with a VP44 PSG16 (SAAB T7) Had the dreaded P1631 yep deado code read indicating “Spill valve relay” So was advised to “change the transistor” in the EDU, Easier said than done, Over 25 years of soldering experience, 3 different solder irons, No way would that solder run for the wires to attach, Eventually damaging other quarter thin hair lines in process, Gave up, Not quite, Recalling the old basics and principals of diesel engines and how they run, Theory is they dont need ECU and EDU to run! When I removed the pump EDU I realised one thing staring me in the face, 2 x black plugs with lots of pins (PSG16) and 2 x pairs of wires going to external valves on back of pump, So hang on a minute (I thought) whatever these multiplugs with lots of wires in them are doing, the end result is 12v down to the 2 x external valves! There is nothing else (apart from a TDC pickup) running from the EDC to the pump, The pump by the way is already timed to TDC via the timing chain! So why not feed 12v directly to the valves and unplug the 2 plugs on the pump, Yes the ECU will have a dicky fit proving itself with a lit EML light (That can be easily tapped onto the airbag lamp to keep the MOT tester happy) with the valves opened by IGN 12v feed, fuel will pump to the injectors, The T7 (Trionic 7) only controls 3 main items, 1 Fuel injection!!!! 2 Boost pressure, 3 Ignition timing – Since all other modules & sensors are still connected to the ECU, It still collects and processes that data to “make it run efficient” LIES LIES LIES and that the ECU cant force the pump EDC to stop because its not in circuit, The ECU cant stop the engine running because there is only sensors attached to it, Your gona say “The pump controls the feed pressure etc” So what, the injectors can only allow a certain amount in the cylinder!!! any excess is returned to the tank! So lets check out the theory, If it starts then will check emissions, If that fails, Wheres a mechanical (CABLED) control pump to be found these days!!!!!

  6. Oh boy I drove my Audi all-road to work as usual but when i came to leave it would not start aa told me the pump had failed so me being me took off the pump and paid £700 for a rebuild i refitted the pump and have struggled ever since to get the timing right in the end after a year i took it to another Bosch center who told me that the pump itself was never timed correctly internally and guess what the first recon people said no guarantee because of self fit

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