DTC 01268 - No start, can't clear code?

CrewCabCaddy

Well-known member
Joined
May 27, 2002
Location
Seattle Area, Washington, USA
TDI
1981 Custom 4-door Rabbit Pickup w/ 6sp O2M
Hi All,

Driving my rabbit with a 1996 1Z TDI installed (engine has about 130,000 miles on it, with about 35,000 miles since install into rabbit), and all of a sudden it starts shuddering and hiccupping and then dies. Try to restart and it over-revs with black smoke, revs back down and then runs rough for a few seconds with white smoke, then dies. glow plug light flashing.

After a couple more similar start ups, engine dies and won't restart. Cranks fine and fast, but no start.

Haul it home on a rental trailer, hook up VAG-COM, have multiple DTCs...clear DTCs. DTC 01268 N146 quantity adjuster 35-00 fault returns immediately after clear. glow plug light still flashing. Still no start

Try alternate ECU and get same code/issues and no start.

Also, about 15,000 miles ago I did hammer mod and advance timing to upper range on graph to account for extended fuel delivery related to chip in ECU.

Did Bently diagnostic for quantity adjuster and modulating piston displacement sensor and do not get appropriate resistance on connector terminals from pump. Wiring to ECU appears fine.

Time for a new pump? Any other thoughts?
 
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rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
I'm unclear as to what exactly happened with the initial event. One possibility is a turbo going into run away mode. If so, more problems than an IP - hence how much oil is in it at this point. I haven't heard of a situation in which the pump causes this type of "over revving". I also am having a hard time understanding why is "shuddered and died" right before being restarted and going into an over rev mode. So, questions are there, but first, does it still have any oil?
 

CrewCabCaddy

Well-known member
Joined
May 27, 2002
Location
Seattle Area, Washington, USA
TDI
1981 Custom 4-door Rabbit Pickup w/ 6sp O2M
Checked oil first thing after initial stall and it was fine. Was running great until it sputtered and died right after a sharp left hand turn and a small puddle. At first I thought water into connectors, but I live in western Washington and this wiring has seen a lot of rain and puddles in past year. I did just install a new clutch, so maybe I knocked a connector loose and didn't see it, and the connector got water into it, shorting something out....??? And I have not run biodiesel in this car yet.

Just spent about 20 minutes on the phone with Kyle at Diesel Injection Service in Portland, Oregon. He ran through some of the potential issues, pulled the Bosch manual for this pump and gave me some more diagnostic information. The number is 1-888-285-1213 and I have to say that based on my phone call, these guys are great. They immediately transferred me to their TDI injection pump mechanic and he spent 20 minutes helping me. We ran through the problems and measurements I made and I will be making some more soon.

Based on the Bosch manual and assuming you have the Bosch pump number 460 404 982 (VW 028130110N) and an HDK quantity adjuster ("HDK-###" stamped on the pump body behind the fuel shut-off solenoid) here are the specifications for the 7-pin connector leading from the pump:

Between pins 4 and 7 - 0.4 to 1 ohm
Between pins 1 and 3 (internal resistor coils) - 4.9 to 6.5 ohm
Between pins 2 and 3 (internal resistor coils) - 4.9 to 6.5 ohm
Between pins 1 and 2 (internal resistor coils) - 9.8 to 13 ohm
Between pins 5 and 6 (temp sensor) - 1.2 to 4 ohm cold
Between pins 5 and 6 (temp sensor) - 0.3 to 1.2 ohm hot
Between pin 1 and ground - 0 ohm
Between pin 2 and ground - 0 ohm
Between pin 3 and ground - 0 ohm

He thought the over-rev could be a sticking sliding sleeve, but my pump looks pretty clean inside the top plate. I may try a new temp sensor also, but evidently that usually won't cause a no start. I'll also loosen an injector line and see if the pump is providing pressure on the outlet side.

I'll run through these and let y'all know what I find.
 
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CrewCabCaddy

Well-known member
Joined
May 27, 2002
Location
Seattle Area, Washington, USA
TDI
1981 Custom 4-door Rabbit Pickup w/ 6sp O2M
Checked resistance between pins and cracked open a pump to injector fuel line connector at the pump end. Resistance was incorrect on all pins. No fuel out!

Buying another pump!
 

CrewCabCaddy

Well-known member
Joined
May 27, 2002
Location
Seattle Area, Washington, USA
TDI
1981 Custom 4-door Rabbit Pickup w/ 6sp O2M
This problem ended up being related to two injection pump wires rubbing against a sharp metal corner and shorting out/melting together.

Given this, I am not sure how reliable the above resistance measures are at establishing whether a pump is bad or not.
 
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Houpty GT

Veteran Member
Joined
Aug 31, 2008
Location
South Carolina
TDI
Corrado TDI, 2000 Golf, 1996 B4 Variant
Based on the Bosch manual and assuming you have the Bosch pump number 460 404 982 (VW 028130110N) and an HDK quantity adjuster ("HDK-###" stamped on the pump body behind the fuel shut-off solenoid) here are the specifications for the 7-pin connector leading from the pump:

Between pins 4 and 7 - 0.4 to 1 ohm
Between pins 1 and 3 (internal resistor coils) - 4.9 to 6.5 ohm
Between pins 2 and 3 (internal resistor coils) - 4.9 to 6.5 ohm
Between pins 1 and 2 (internal resistor coils) - 9.8 to 13 ohm
Between pins 5 and 6 (temp sensor) - 1.2 to 4 ohm cold
Between pins 5 and 6 (temp sensor) - 0.3 to 1.2 ohm hot
Between pin 1 and ground - 0 ohm
Between pin 2 and ground - 0 ohm
Between pin 3 and ground - 0 ohm
I wanted to post to this thread to correct what I find as incorrect info on the following website as well as the Bentley. These numbers should apply to the same pin numbers on an ALH style pump also. Any quantity adjuster is swappable among these cars. http://audi.workshop-manuals.com/a4-mk1/index.php?id=1846

Pins 4 and 7 go to the fuel temp sensor G81
Temp sensor resistance should be around 1,500 ohms at about 70 degF.
Pins 5 and 6 go to the Quantity Adjuster (electromagnetic coil) N146
Pins 1, 2, and 3 go to the Modulating Piston Displacement Sensor G149

Hopefully this saves someone from thinking they have a bad pump.
 

NickStock

New member
Joined
Oct 26, 2009
Location
UK
TDI
A80, Passat
Just to add to the information .... I had the 01268 qa code on my a4 quattro .. turned out the previous owner had been running on a mix of veg oil and white spirit ... ran badly really lumpy ... took the whole control unit off the top of the pump ( use lots of rags and clamp the lines obviously),,, inside was a horrible mess of orange gunge everywhere ... soaked it in petrol for a few hours ,, cleaned it all off with a soft toothbrush ... if you need to fully clean it inside you have to desolder the terminals ..set it back up ..hey presto fault gone ... also if you have a fuel sender fault ..gauge flicking around etc.. again poor quality biofuels leave crap everywhere !!!
 
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