Fuel system pressure too low - P00C6 00

Hello everyone!

Today, I replaced the fuel filter on my Golf 6 1.6 TDI.

After trying to start it, it initially started, but after a few seconds it stalled and now it won't start again. I've tried several times, but the Golf just cranks, but doesn't start. I opened the fuel filter again, and the filter is full of diesel, so there's fuel getting to it.

According to VCDS.

Sure, here is the translation of the text from German to English:

"1 error found:"

10119 - High fuel pressure.
P00C6 00 [100] - Minimum pressure not reached.
Sporadically - unconfirmed - checked since last deletion.
Environmental conditions:
Error status: 00000001
Error priority: 2
Error frequency: 1
Mileage: 238,147 km
Date: 2023.01.07
Time: 15:22:56

Motor speed: 278.75 RPM.
Normalized load value: 10.6%
Vehicle speed: 0 km/h
Coolant temperature: 26 °C
Intake air temperature: 13 °C
Ambient air pressure: 930 mbar.
Voltage at terminal 30: 9.713 V.
Lost count after OBD: 40
Fuel high pressure: Actual value - FUP_FIL: 0.000 MPa.
Fuel pressure control valve: Target rail pressure - LV_PCV_CTL: 00000001.
Fuel reserve - FTL_CAN: 22 liters.
Time since engine start: 0 s.
Fuel metering valve: 25.302%
Fuel pressure control valve (PCV) solenoid valve: 47.470%
Fuel high pressure commanded value_1-FUP_SP_KPA_ENVD: 28149.414 kPa


Readiness: 0 0 0 0 1



I also ran program 00459 using VCDS, cleared the error codes, and tried to start the engine again, but it just cranks and doesn't start.

Do I need to bleed the system in a different way? Does anyone have any tips on how to get the engine running again?

Thank you very much.

Hi,

Check this out...

/viewtopic.php?t=27765

This procedure can be repeated a few times without any problems.

Don't just start playing randomly, hoping it will somehow work out eventually!
That could be bad for the high-pressure pump!

It's best to change the fuel filter when there's enough fuel in the tank; I've already had problems when it was down to "reserve."

Best regards, Richard.

Hello Richard,

Thank you for your feedback and the link.

I've already tried channel 35 before, but without success.

I have a question regarding this: What is the difference between channels 00459 and 0035? Do you think they both perform the same procedure?

As I said, I've tried channel 35 several times. How many times should one do it? I've probably done it at least 5 times, which should be enough, right?

Moved the vehicle this morning, meaning it was running, fuel tank was almost half full, so it can't be a fuel issue since it started, but then unfortunately it died.

My approach with VCDS was unfortunately only done after the car had turned off, i.e., this procedure with channel 35 and 459 would be more useful to do before starting the car, and that was unfortunately my mistake .

It's possible that air entered the system after I started it, because the filter was wet but not completely full. Later, after I primed it more times and performed the procedure with codes 35 and 459 using VCDS, and after I opened the filter, I saw that it was completely full of diesel, which means that fuel is being pumped.

I understand that organ playing is currently unwanted, so I'm trying to minimize the errors as much as possible before attempting to start again.

What other options do I have?


P.S. I just tried a few more things (selective actuator diagnosis) using a relay for the fuel pump, but unfortunately, it didn't work. The battery is now empty, so I need to charge it. I will try again tomorrow.

I would like to provide the Autoscan log file. Perhaps someone here might have some insight and be able to take a quick look to see if they can identify the cause.

Quote:

I have already tried channel 35 several times, but without success.

What do you mean by "in vain"?
After being turned on, the pump doesn't run (you can definitely hear that it's not working).
or
After the system is primed, the pump is running audibly, but the engine still won't start?

Quote:

(...)I opened the filter again, the filter is in the diesel, so, there is fuel.

That means it's a filter housing that screws on, and only the filter element itself needs to be replaced?
Is the filter housing lid sealed tightly?
Are the fuel hoses to the cap also tight, and are the hose clamps secure?

"In our 1.6 TDI, the entire cartridge is replaced, although this is a Polo 6R."

The pump is being activated, and you can clearly hear it, but the engine is not starting.

"That's right, the filter element inside the cartridge is replaced, meaning only the filter is changed, along with the sealing ring, which I also replaced. The lid is screwed on tightly, I haven't touched the hoses, and everything looks sealed. I can't imagine what could have gone wrong that it won't start anymore..."

I'm quite at a loss. I have to go to work on Monday, and this was the only vehicle I could use.

I regret now that I touched the fuel filter, even though it was terribly dirty, which means it was actually long overdue for replacement.

Can I try something else?

If the old filter element was so dirty, was the housing emptied and cleaned?

How long does the pump run when it is started for the first time?
Sure, here's the translation:

"It should be between 20 and 30 seconds."

Quote:

Can I try something else?

If you feel that the filter housing is completely full, you can try initiating a normal startup sequence immediately after the pump has been primed, using VCDS...

Good luck!

Quote:

If the old filter element was so dirty, was the housing emptied and cleaned?

Unfortunately, I didn't empty the housings; they contained diesel, and I just installed the new filter.

Quote:

How long does the pump run when it is started once? It should be

between 20-30 seconds.

The process takes about 30 seconds in total. It involves several short cycles with brief pauses in between. I estimate that the initial cycle takes about 10 seconds, followed by a few more cycles, and then it stops after about 30 seconds.


I'll try starting it again tomorrow when the battery is fully charged. If it doesn't start, I'm afraid something serious might have happened. It's possible that the high-pressure pump could have been damaged. Is there any way to check that?

I'm trying to loosen the fuel lines connected to the fuel injectors to see if any fuel is still flowing through them.

Are there any other ways to start the engine using brake cleaner sprayed into the intake manifold?

"Can I directly tap into the diesel supply line from a canister? If so, could someone give me a tip on which lines to disconnect? I'm not sure which is the supply and which is the return line. Has anyone done something like this before?"

Just a quick reminder: Please avoid using brake cleaner or similar products.

Rüdi wrote:

Just a quick fix, avoid using brake cleaner or anything similar

.

Okay, I understand now, thank you very much!

Hi,
Use the "prime fuel pump" or "initial fill" function.
Then, please note:
"The fuel pump must run for approximately 3 minutes to ensure that the high-pressure pump is adequately filled with fuel."
These specifications for the Golf 7 1.6 TDI should also be applicable to the Golf 6.
hg
Herbert.

Hello everyone.

Okay, here's my feedback. Unfortunately, as suspected, attempting to access the fuel pump procedure didn't yield any results.

However, I have found a solution, and I would like to briefly describe it here, especially for laypersons like myself.

After some consideration, I've concluded that there must be air somewhere in the lines. No matter how many times you activate the fuel pump, if there's air between the fuel filter and the high-pressure pump in the lines, these actions – activating the fuel pump or using a selective actuator diagnosis with the fuel pump relay, as in my case – unfortunately won't help.

My solution was as follows:

I disconnected the hose (in the picture, hose number [Admin: likely the fuel return line from the diesel filter], and there wasn't a drop of fuel in it. Then I used the hand pump to pump until fuel started flowing, reconnected the hose, and tried to start the engine, and it immediately started.

So, if adjusting the fuel pump or using (selective actuator diagnostics) with a fuel pump relay doesn't work, here's another option that might help.

To the guys in this forum, thank you very much for the tips!

I hope that Golf continues to serve us for a while longer.

Best regards to everyone here, and have a lovely Sunday evening!

"For years, I've generally done this whenever the fuel area was exposed: I would insert a rubber bellows pump and then ignite it."

Hi,

Due to unclear image rights, I have temporarily removed it.
Please verify information before posting anything. I've followed up and hopefully I'll receive a response soon.

Was was bleded out at the fuel return line, correct?

Best regards, Rainer.

Hello Rainer,

Sorry, I didn't have the "rights" issue in mind. Here's my photo of the part with the arrow. I'm not sure which line it is, whether it's the return line or not. Unfortunately, I suspect it's the supply line to the high-pressure pump.

Best regards,