Audi A6 2.7tdi glowplug light flashing/limp mode

[gringosmith]

All was going well with my Audi A6 2008 2.7tdi Manual Estate until it stopped suddenly back in April. Diagnostics showed "Crankshaft Position Sensor Fault", however changing this did not get my car started, and two garages including an independent Audi specialist gave up on the car. The fault was finally traced to a damaged tooth on the flywheel caused by a piece of metal coming away from the clutch plate. One new dual mass flywheel and clutch later the car was up and running again, however.......

The glow plug light started flashing, and the car went into limp mode as soon as I went over 2,500 - 3,000 revs or so. The diagnostic report shows "004195 - Fuel Pressure Regulation P1063 - 001 - Control Range Not Reached - Intermittent". See log:

004195 - Fuel Pressure Regulation
P1063 - 001 - Control Range Not Reached - Intermittent
Freeze Frame:
Fault Status: 00110001
Fault Priority: 0
Fault Frequency: 8
Reset counter: 255
Mileage: 121992 km
Time Indication: 0
Date: 2007.10.25
Time: 09:47:04

Freeze Frame:
RPM: 3717 /min
Torque: 374.4 Nm
(no units): 5.0
Voltage: 13.53 V
Pressure: 1178.6 bar
Duty Cycle: 53.3 %

No other faults are present, and turning ignition off and on clears the fault until next time 2500 - 3000 revs.

I have changed the fuel filter, changed the valve on top of the fuel filter, tried a new air mass meter, removed the injectors and had them all tested by a reliable person, checked for any leaks in the fuel lines etc., changed the brake pedal switch (and clutch pedal).

When the previous garages were trying to resolve the crankshaft position fault, they tried fitting a new high pressure pump (then removed when it made no difference), and removed the ECU and had that tested. Somewhere in all of this I think one of them has caused this problem as it was not there before. As the car still runs, I have tried replacing the various parts mentioned over the last 6 months, but I would like my full power back....................Any ideas?

[MarkTM]

Is yours a kosher VCDS, reason I ask is the date of the fault shown as 2007. prior to your car being made!

Also if it's diagnosing a FPR fault have you thought to change?

Genuine pressure-relief valve Audi A3 A4 A5 A6 Q5 Q7 TT | eBay (http://www.ebay.co.uk/itm/Genuine-pressure-relief-valve-Audi-A3-A4-A5-A6-Q5-Q7-TT-/261813129790?hash=item3cf547523e:g:110AAOSwrklVBdc m)

I've googled (you can do the same)

It throws up:

Fuel filter
Leaking injector
Bad fuel pump
FPR gone bad

PS: Using the measuring blocks in VCDS you can check the fuel usage against what's being requested, but once again google would have given you that answer (and how to do it) too.

[Advanced-Tuning]

I would swap the rail sensor out if it was me, seeing you have changed the fuel filter already. The code suggests its not making the required fuel pressure

I am also extremely sceptical of ECU testing complanies. There isn't anything they can really test on that EDC16/17 ecu off the car,

Also remove the ecu plugs and check they haven't bent any pins

[gringosmith]

Thanks for your inputs. The 2007 date on the log is just because the battery must have been disconnected when the guys were working on the car, so that's an easy setup function to correct - done.

I have googled and read virtually everything on this fault code, on UK sites as well as European & US, but have not found a definitive answer. I am sure this is something silly, that one of the (so-called) mechanics has messed up, but I am trying to work logically and methodically through the process without throwing excess parts and money at the car.

I have ordered a Fuel Pressure Regulator Valve, and will also try to work out which VCDS measuring block codes monitor fuel rail pressure; actual v required.

I appreciate your comments and assistance - thank you.

Will update when progress made.

[Advanced-Tuning]

Fpr valve is different from the fpr sensor i suggested

[gupsterg]

gringosmith,

Not that I know how to fix you car, just thought you may wanna ref this info to aid you DIY diagnosis.

First google SSP 350, ref pages 26 & 27, this will give you overview of injection system.

Next google SSP 351, this will not get you right file but download first hit, page 30 & 31 cover N290 fuel metering valve. The fuel pump diagrams are for later 3.0 TDi (09-11) but info is relevant. The N290 on your fuel pump will be on rear, not top at a side. Page 33 covers G247 fuel pressure sensor, pages 34 & 35 cover N276 fuel pressure regulating valve.

Read thoroughly take note of functions, effects of failure.

If you have to change N290, Audi dealer will be with complete fuel pump but you can get new genuine via another route, read this post (http://www.vwaudiforum.co.uk/forum/showthread.php/102358-audi-3-0tdi-engine-measurement-blocks?p=834224#post834224). Also that thread has measuring blocks info, even if its A4 3.0TDi info is same.

I'd probably set up MVB 01 , 22 , & 23 to view, IIRC 22 gives you activation of N276 in data window 4, 23 gives you activation of N290 in data window 4.

I'd also run a output test in module 01, this will test electrical response to ECU signal for N276 & N290, if you remove those sensors and VCDS is running output test you'll see if they are responding mechanically. Output text is run engine off.
I'll PM you some links, one of them has test for N276 when engine at idle to see if leaky fuel=loss of pressure in rail. If you want SSP 351 request via PM as online can only see German version and not English.

This may also be handy, item 2 = N276, item 3 = G247, item Link:- AUDI A6/AVANT [A6] (EUROPE) 2008: ENGINE: 13070. FUEL RAIL; INJECTOR UNIT; PRESSURE PIPES (http://www.partsbase.org/audi/audi-a6-avant-a6-eu-2008-13070-fuel-rail-injector-unit-pressure-pipes/)

[gringosmith]

Many thanks for all this useful info - especially the measurement codes to run.

I'll try these as soon as I have some time and give you feedback.

[gringosmith]

Audi A6 2.7tdi glowplug light flashing/limp mode - RESOLVED

Yes I know it's taken a long time but the car has been drivable despite the fuel pressure problem, and I don't want to be without car for my business.

So the I had previously changed the fuel filter (http://shop.ebay.co.uk/?_nkw=fuel+filter), changed the valve on top of the fuel filter, tried a new air mass meter (http://shop.ebay.co.uk/?_nkw=air+mass+meter), removed the injectors and had them all tested by a reliable person, checked for any leaks in the fuel lines etc., changed the brake pedal switch (and clutch pedal switch).

Finally a week ago when the car was being serviced I had my mate fit the new fuel pressure relief valve which I bought a good few months ago. Picked the car up and gave it some welly and low and behold there was no longer the annoying glowplug light, or limp mode, despite trying my hardest with my right foot to trigger the sensor.

So I am guessing that the fuel pressure relief valve was fine at retaining pressure at 10 bar when the engine was stopped, but when accelerating heavily, it was letting fuel pass through slightly; enough to trigger the fuel pressure fault.

Thanks for everyone's input, and I hope in posting this solution, it may help someone else with the same problem.

All the best, Neal

[kimlk]

Eh.. Never mind. Brainfart and "quick reply"..
Did you ever resolve this? I just got the same fault code in my A6.

[gringosmith]

Yes, all resolved with a Fuel Pressure Relief Valve bought from Germany or Poland online (I forget which).

Are your fault codes and readings similar to mine? Is it only when you accelerate hard, and when the engine has warmed up a little?

[kimlk]

Yes, but with MIL ON. Ok at startup, goes into limp mode when pushed.

004195 - Fuel Pressure Regulation
P1063 - 001 - Control Range Not Reached - MIL ON
Freeze Frame:
Fault Status: 11110001
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 247425 km
Time Indication: 0
Date: 2016.10.18
Time: 21:10:14


Freeze Frame:
RPM: 2184 /min
Torque: 425.1 Nm
Speed: 33.6 km/h
Duty Cycle: 62.8 %
Voltage: 13.76 V
Pressure: 355.0 bar
Duty Cycle: 42.6 %


004195 - Fuel Pressure Regulation
P1063 - 002 - Control Range Not Reached - Intermittent
Freeze Frame:
Fault Status: 11110001
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 247425 km
Time Indication: 0
Date: 2016.10.18
Time: 21:10:14


Freeze Frame:
RPM: 2184 /min
Torque: 425.1 Nm
Speed: 33.6 km/h
Duty Cycle: 62.8 %
Voltage: 13.76 V
Pressure: 355.0 bar
Duty Cycle: 42.6 %

[kimlk]

Did some tests. First I checked the injectors. Volume of fuel from return was within specified volume of <50 ml when idling for 2 min and less than 250 ml at 2000 rpm for 2 min. Also did the test an pressure regulating valve. However, I hope I did it wrong. –Perform check at starting speed. Specification: return flow rate = 0 ml at starting speed If specification is not obtained, fuel pressure regulating valve -N276- is defective. When I started the engine, the flow from the return hose was rather high. I was not able to check the moment I started the engine. Is it supposed to be noe return flow just the moment one tries to start the engine? The engine starts and the fuel in return hose starts to flow like it should.. I hope? I still only get the abovementioned fault code, and I am leaning towards the fuel retention valve. What do you think?

[kimlk]

Took the plunge and bought a new pressure retention valve with fuel lines.. Not a cheap assembly.. Changed, seemed fine at startup. But as soon as I got out on the road the light came back on and the car went into limp mode. Crap... Got this freeze frame
Freeze Frame Data for address 7E8
PID02 DTC that caused freeze frame data storage: P0087
PID04 Calculated load value: 79.2 %
PID05 Engine coolant temperature: 81 °C
PID11 Intake Manifold Absolute Pressure: 107 kPa abs
PID12 Engine RPM: 1365 /min
PID13 Vehicle speed: 6 km/h
PID15 Intake air temperature: 19 °C
PID16 Mass Air Flow: 31.36 g/s
PID17 Throttle position sensor: 34.5 %
And from readiness test i got,
Mode 01 - PID 01 : Readiness -- Address 7E8


Number of DTCs stored: 0 -- MIL Status: MIL OFF
Misfire monitoring: Not installed.
Fuel System: Failed or Incomplete
Comprehensive Components: Failed or Incomplete
Catalyst monitoring: Not installed.
Heated catalyst monitoring: Not installed.
Evaporative system monitoring: Not installed.
Secondary air system monitoring: Not installed.
A/C system refrigerant monitoring: Not installed.
Oxygen sensor monitoring: Not installed.
Oxygen sensor heater monitoring: Not installed.
Exhaust Gas Recirculation: Failed or Incomplete

Can anyone interpret this? What makes the EGR fault? Does not come up as a fault code.

I am just about to give up and turn the car in to a workshop...

[MarkTM]

Kimlk

Have you also changed your throttle position sensor like Gringo has?

Ask as that % reading seems very low?

I believe the part number for the 2.7 & 3.0 is

A8240C04/06E-905-163 (both VW part no's for the UK for the crankshaft sensor)

[kimlk]

Hello, no I haven't. Should the readings be higher at so low revs? I was very gentle on the throttle in the start, so I know the pedal was not far from the top.

[MarkTM]

Apologies I misread as crankshaft positioning sensor so disregard my advice and the part number :(

[kimlk]

Did a log of MVB 22. From what I have read the first pressure is specified, end the next is actual. The pressure seems to fluctuate quite a bit, and is no where near 1600 bars even at high rpms. What to try next?

STAMP
/min
bar
bar
%




7.31
2037
447.3
411.8
24.1


7.48
2037
447.3
475.7
24.1


7.64
2037
447.3
440.2
24.5


7.79
2037
447.3
404.7
24.1


7.95
2037
447.3
475.7
24.5


8.12
2037
447.3
397.6
24.5


8.28
2037
447.3
383.4
24.1


8.43
2037
447.3
518.3
24.5


8.59
2037
447.3
447.3
24.5


8.76
2037
447.3
426.0
24.5


8.92
2037
447.3
411.8
24.5


9.07
2037
447.3
362.1
24.5


9.23
2037
447.3
497.0
24.5

[kimlk]

3202432025
Guess I found the culprit. No more teeth on the belt. Learned a lot, and bought another engine before checking this. Expensive work for a not expensive fix. Kind of annoying, but at least noe I know why I have had trouble.

[MarkTM]

Is that the auxiliary belt?

Has it been changed in your ownership?

My feeling is that if huge chunks have been gouged out of it something is wrong with the alignment of one or more of your pulleys, replacing may give you an immediate fix but it may reoccur if the cause isn't remedied.

Still don't understand how it's failure can lead to fuel pressure anomolies....but if your car is running now problem free then it must:confused:

[kimlk]

No, it's the hpfp drive belt... Seems its no service interval on it. Will change it tomorrow. Hopefully that will fix the problem.

[MarkTM]

Post up the part number if you could, I've not taken mine apart but since my car (with the same P1063 fault) hasn't started in over 2 months, it's a possibility that I should look at before I replace the whole pump.

Also everything I've read recommends changing the tensioner as well, will you be changing that as well?

Belt = 059109119D - £34.84 Inc
Tensioner = 059109243P £83.80

[MarkTM]

Also how easy is it to get the cover off the front of the belt, just looked and I can't find any release tabs?

[gupsterg]

Tabs should be to the left and right sides of cover.


http://i.imgur.com/Mr5VvGW.jpg


Engage googles for audi workshop, then select A4 MK3, then select Power Unit, then select TDI injection and glow plug system (6-cyl. 2.7�ltr., 3.0�ltr. 4-valve com , then select Toothed belt (CAPA) and you'll see 2 relevant sections ;) .

[kimlk]

Replaced tensioner and belt. Took tensioner from a donor engine I bought when I thought it was the hpfp. I managed to change it without having to take off the camwheels. Loosened the cover, snook the belt in and assembled. Took out a lot of gunk from the intake. Used the spare from donor engine, and will clean the other thoroughly before replacing. Car is good to go again. Annoying £35 problem..

[MarkTM]

Thank kimlk

No special tools needed?

[MarkTM]

Well took mine apart today and it's not the hpfp belt or tensioner, as both look/feel OK

32051


So in my case most probably the hpfp itself, have ordered one off ebay which at less than £100 is less than a 15th the price that Audi want for a new one.