Good morning, I've been having an issue with my 2.0 TDI A4 (CAHA), where it will crank and get close to starting but will not start fully.
It began this when I was driving down a dual carriageway and it went into limp mode, which once I reached the drive it would not start back up.
It has started once, but was extremely rough on idle so I shut it back off.

I've read the logged DTCs via VCDS and this is the initial reading -

Quote

5211 - Fuel Rail/System Pressure
P0087 00 [01100100] - Too Low
Intermittent - Not Confirmed - Tested Since Memory Clear

5141 - Random/Multiple Cylinder Misfire Detected
P0300 00 [01101101] - -
Confirmed - Tested Since Memory Clear

These DTC's have been logged, cleared and have not come back on after the one or two cranks I did to get the sensor logs.

From this, I did some investigation through other forum posts with people mentioning the High Pressure Fuel Pump (HPFP) can fail catastrophically and cause fuelling issues. There does not seem to be any metal flakes in the return from the HPFP or under the sensor in the HPFP.

I do have two live sensor logs attached of when I've attempted to crank the car over, and when it has gotten close to starting.

Hopefully someone is able to point me in the right direction and what to look at from here, as I'm at a bit of a loss. She's a lovely spec and would love to keep her on the road.

 

 

LOG-01-IDE00076_&11-new.CSV LOG-01-IDE00076_&12-new.CSV

Ha e the injectors been tested?

Could it be a crank sensor? 

What condition is the fuel filter? 

Changing the HPFP is very expensive and has to be coded. 

Is there any red light on the dash etc to indicate an imobiliser issue? 

5 minutes ago, Steve Q said:

Ha e the injectors been tested?

Could it be a crank sensor? 

What condition is the fuel filter? 

Changing the HPFP is very expensive and has to be coded. 

Is there any red light on the dash etc to indicate an imobiliser issue? 

The injectors have not yet been tested, what would be the best course of action to test the injectors?

I've got a crank position sensor arriving tomorrow, along with a new fuel filter, so from that hopefully it will rule them out. Have not yet seen the condition of the filter but will have a look tomorrow.

I've seen the costs and everything involved with the HPFP, and yeah its certainly the last course of action I want to take.

The immobiliser doesn't seem to be the cause, there's been no DTCs relating to immo issues and I've had no red light on the dash to indicate such.

Thanks

2 hours ago, Refrigerator said:

The injectors have not yet been tested, what would be the best course of action to test the injectors?

I've got a crank position sensor arriving tomorrow, along with a new fuel filter, so from that hopefully it will rule them out. Have not yet seen the condition of the filter but will have a look tomorrow.

I've seen the costs and everything involved with the HPFP, and yeah its certainly the last course of action I want to take.

The immobiliser doesn't seem to be the cause, there's been no DTCs relating to immo issues and I've had no red light on the dash to indicate such.

Thanks

Hi my guess is its the lift pump in the tank they are not monitored on that year and that would throw up the low pressure rail fault, can your diagnostics monitor the low pressure pump in the tank at idle as if its anything above 400 at idle the pump is gone.

Steve.

15 hours ago, Stevey Y said:

Hi my guess is its the lift pump in the tank they are not monitored on that year and that would throw up the low pressure rail fault, can your diagnostics monitor the low pressure pump in the tank at idle as if its anything above 400 at idle the pump is gone.

Steve.

That's interesting, and was the direction I was going to look into. I'm going to be working on the car later so I'm going to give a few things a shot and report back.

Poked around VCDS a little more and made another log, unfortunately have not had the time to go any further with replacing the fuel filter or crank pos sensor today.

This log includes crank speed, engine speed and mean injection quantity so hopefully its a little more helpful.

 

I've also ran a "test of transfer fuel pump", can clearly hear it come on but didn't have time to test flow.

(apologies for the long start to the log)

LOG-01-IDE00021_&14-crank-edit.CSV

13 hours ago, Refrigerator said:

Poked around VCDS a little more and made another log, unfortunately have not had the time to go any further with replacing the fuel filter or crank pos sensor today.

This log includes crank speed, engine speed and mean injection quantity so hopefully its a little more helpful.

 

I've also ran a "test of transfer fuel pump", can clearly hear it come on but didn't have time to test flow.

(apologies for the long start to the log)

LOG-01-IDE00021_&14-crank-edit.CSV 4.68 kB · 0 downloads

Hi sorry can't read the format of the log as it seems  to be word or something similar.

Steve.

17 hours ago, Stevey Y said:

Hi sorry can't read the format of the log as it seems  to be word or something similar.

Steve.

Ah that's strange, I thought it sent as a generic CSV. Hopefully this one works!

LOG-01-IDE00021_&14-crank-edit.CSV

Leo.

They are both .csv files. Many computers will not automatically recognise them, and have to be told what to do. For anybody willing to download the file, (which I am not,) it should be capable of being opened with a spreadsheet application.

3 hours ago, Refrigerator said:

Ah that's strange, I thought it sent as a generic CSV. Hopefully this one works!

LOG-01-IDE00021_&14-crank-edit.CSV 4.68 kB · 2 downloads

Hi nope still can't open it, tried various ways and eventually got the message that the Mac is convinced it may be the file is infected.

Steve.

On 8/17/2025 at 5:24 PM, Stevey Y said:

Hi nope still can't open it, tried various ways and eventually got the message that the Mac is convinced it may be the file is infected.

Steve.

Darn, my apologies. I'll provide the information in screenshots or in quotes if that's okay for you to read (hopefully the text isn't too small).

Original DTC's that have since been cleared and have not come back up:

Quote

5211 - Fuel Rail/System Pressure 
          P0087 00 [01100100] - Too Low
          Intermittent - Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 251097 km
                    Date: 2025.06.06
                    Time: 15:19:24

                    Engine speed: 1667.50 /min
                    Normed load value: 44.7 %
                    Vehicle speed: 0 km/h
                    Coolant temperature: 76 �C
                    Intake air temperature: 31 �C
                    Ambient air pressure: 1000 mbar
                    Voltage terminal 30: 14.020 V
                    Unlearning counter according OBD: 80
                    Fuel temperature: 25.1 �C
                    Mean injection quantity: 15.34 mg/stroke
                    Rail pressure regulation: status-Bits 0-7: 5
                    Fuel high pressure: actual: 302300 hPa
                    High fuel pressure: specified value: 675800 hPa
                    PCV fac Adapt: 1.0692
                    Com vol Fl Tnk Qnt: 24.00 l

 

5141 - Random/Multiple Cylinder Misfire Detected 
          P0300 00 [01101101] - -
          Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 251097 km
                    Date: 2025.06.05
                    Time: 09:29:32

                    Engine speed: 807.50 /min
                    Normed load value: 69.0 %
                    Vehicle speed: 0 km/h
                    Coolant temperature: 47 �C
                    Intake air temperature: 15 �C
                    Ambient air pressure: 990 mbar
                    Voltage terminal 30: 14.080 V
                    Unlearning counter according OBD: 40
                    Mean injection quantity: 18.97 mg/stroke
                    Actual air mass: 386.3 mg/stroke
                    Fuel temperature: 25.1 �C
                    Lambda signal: 1.579
                    PCV fac Adapt: 1.1021
                    Inj Crv st Inj Char Act Val 0-Bits 0-7: 56

The screenshots below are separate crank attempts, both with a decently charged battery. Both have cranked until the ECU stops cranking.

 

An interesting discovery I've just made is when making a log a few minutes ago for "Injector Quantity Deviation" for each of the cylinders, they are all reporting as 0 mg/stroke (shown below). Am I correct in thinking this is not normal?

In a correction to my previous post, the injection quantity deviation may not actually be as bad as I thought as its only relevant once the engine is running (or so i've heard).

It gets close to starting by the sounds of things and by the looks of the RPM.

Another thing I noticed is that the RPM needle is not moving when cranking, even when the engine speed that is reported via CAN reaches 400+ RPM.

 

The videos below shows the vehicle cranking, with there being no movement of the tachometer.

 

Edited August 18, 2025Aug 18 by Refrigerator
To add the Youtube videos

15 hours ago, Refrigerator said:

In a correction to my previous post, the injection quantity deviation may not actually be as bad as I thought as its only relevant once the engine is running (or so i've heard).

It gets close to starting by the sounds of things and by the looks of the RPM.

Another thing I noticed is that the RPM needle is not moving when cranking, even when the engine speed that is reported via CAN reaches 400+ RPM.

 

The videos below shows the vehicle cranking, with there being no movement of the tachometer.

 

Hi that code pretty much points straight at the lift pump, done a 2014 A4 recently same code, so we bought a second hand pump from the local VW dismantlers and bingo all good.

Steve.

1 minute ago, Stevey Y said:

Hi that code pretty much points straight at the lift pump, done a 2014 A4 recently same code, so we bought a second hand pump from the local VW dismantlers and bingo all good.

Steve.

Ah lovely, was going to get a new / second hand lift pump anyway to rule it out. Shall get one ordered asap and get it all fitted and see what happens.

 

Thank you Steve