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Had some shuddering and engine power issues and replaced the HPFP. Did drain the tank to see if there was any muck in there but it was squeaky clean. Didn't replce the in-tank pump and filter though. Now car cranks with full power and wont fire up. Jumped the fuel pump relay 3+4 pins and still wont fire. Every time I turn the ignition on the pump in the tank is prming and I can hear it run while cranking. What should I be checking before replacing the pump and filter?


Only error message that pops up is the reduced engine power after a long crank and goes away when cleared thru durametric.

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Hi Loren,

I did get an error a couple months ago pointing to high pressure sensor ( the one that is attached to the fuel rail) and I replaced it. Is there another sensor I should be looking at? The current codes I see are:



Transmission mount valve 1/2 N262-I-N263 short circuit to B+

Value below lower limit value


Can Gateway



Both these errors go away when I clear it and come back after a few tries. The Transmission error is something new that just popped.


Once I clear the codes the crank lasts long (when turning the key and holding it. Then it suddenly switched to spurts of cranks.


Should the new HPFP be coded to the DME like some other replaced parts?

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  • Admin

The fuel low pressure is regulated by the control unit based on a map. The pressure is monitored by a fuel low-pressure sensor mounted on the distribution pipe to the two high-pressure pumps.

The fuel high-pressure is generated by two demand-controlled fuel pumps driven by the intake camshaft. The quantity control valves of the fuel high-pressure pumps regulate the fuel pressure based on demand in accordance with a map in order to achieve optimum combustion and low fuel consumption combined with high power and high torque. A routine in the PIWIS tester allows testing of the fuel high-pressure pumps by pump selective activation and measurement of the generated fuel high pressure at the fuel high-pressure sensor. In the event of a fault, the faulty fuel high-pressure pump can be detected with the high-pressure sensor on the rail.


It sounds like you still have a fuel circuit problem.

Sorry, but you are likely to have to put a PIWIS or PIWIS 2 tester to see all the errors and to do further diagnosis.

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Before I take it to the dealer I'd like to try and resolve it if I can.


The engine was starting fine before the HPFP replacement. Other work done while I was in there - thermostat replacement, clean valve deposits, sparkplugs. These should not cause the no-fire issue. Battery was disconnected the entire time.


Question for you:

- Is there any steps I needs to do after replacing the HPFP?

- If the tank pump is running does it always mean the fuel supply is fine?

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  • Admin

Repairs in the high-pressure area resulting in air getting into the high-pressure system - you will need to perform the following.


Filling and bleeding the fuel distribution pipe

1. Start the engine and let it run at idle speed for about 5 minutes. This can result in a rough-running engine and the Check Engine warning light in the instrument cluster can be activated.

- If this happens, continue with Step 2.
- If this does not happen, continue with Step 7.
2. Turn off the engine after letting it run for 5 minutes and switch off the ignition.
3. Switch on ignition.
4. Read out and erase the fault memory of the DME control unit using the PIWIS Tester.
5. Switch off ignition.
6. Switch the ignition on and start the engine.
If the engine is still rough-running, let the engine run again for around 5 minutes at idle speed. Then repeat Steps 2 to 6 as often as required until you get to Step 7.
7. The bleeding process is complete when the engine runs smoothly, the Check Engine warning light is no longer activated and no new faults are entered in the fault memory.
8. Perform a test drive.
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  • 2 weeks later...

Finally figured it out and resolved it. One of the snap on tubes connecting from the fuel pump to the fuel filter had popped out. Guess I didnt snap it on properly. Started right back. Can't believe how clean the fuel tank is. Not a speck of dirt given all that I've read about dirty fuel.

Edited by bala
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