ALH Constant Limp Mode 4 Fault Codes

Momentslater

Well-known member
Joined
Feb 2, 2018
Location
Calgary, AB, Canada
TDI
2003 Jetta 390k km
I'm looking for some advice on the issues I'm having with my car right now. Was driving away from a light and at about 50kmh the car just fell on its face, the car was running really rough and had 4 codes when I checked the car when I got home:

16629: N75 Short to Ground
16486: MAF signal too low
16600: N108 Circuit Malfunction
17068: Glow Plug Control Module (J179) impassable signal

I've reset the timing and the car seems to only run with the injection pump advanced off the chart. Nothing changes when I unplug the MAF and I've put in a known good N75 with no change there as well.

No clue what to be looking for here, kinda lost. Any advice is greatly appreciated!
 

Momentslater

Well-known member
Joined
Feb 2, 2018
Location
Calgary, AB, Canada
TDI
2003 Jetta 390k km
Yes I am using VCDS. Unfortunately all the common solution refers to an electronical issues but all these components are on different harnesses
 

STDOUBT

Veteran Member
Joined
Jul 30, 2007
Location
Portland, effing Oregon
TDI
dos jettas

Powder Hound

Top Post Dawg
Joined
Oct 25, 1999
Location
Under a Bridge, Crestview, FL, USA
TDI
'00 Golf 4dr White 5sp, '02 Jettachero 5sp, Wife's '03 NB Platinum Gray auto(!)
I haven't run down any of these electrical items since I've never had these problems, but so many seemingly unrelated components failing at once makes you wonder. The only logical solution for all this stuff failing at the same time is a plug somewhere that came undone. Or loose enough not to make contact. Or a ground wire coming loose. Or...

Something like that where these things all consolidate together, even though the wiring seems independent. They will come together eventually.

Grounds coming loose can cause backfeeds of current and make the most screwy things happen. Don't think that you can ignore them because the first ground wire you find is solid.

Good luck. This type problem can make you bang your head against the nearest wall.

Cheers!

PH
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Any history? Kind of looks like the vacuum lines are shot or not routed correct.
 

wonneber

Top Post Dawg
Joined
Oct 12, 2011
Location
Monroe, NY, USA
TDI
2014 Jetta Sportwagen, 2021 Atlas,2003 Jetta 261K Sold but not forgotten
Long shot.
With the car running, light and AC on:
Measure the voltage from the negative post of the battery to the case of the transmission, then to a body ground near the headlight.
I would not want to see more then a few tenths of a volt.

If the ground under the battery is bad then anything that grounds to the body is bad.

Last, the message "Short to Ground" may mean no power.
I have not been able to confirm this.
 

Momentslater

Well-known member
Joined
Feb 2, 2018
Location
Calgary, AB, Canada
TDI
2003 Jetta 390k km
Thanks for all the assistance guys, I have solved the issue and the fault was caused by a blown fuse #34 in the fuse panel by the drivers door, I replaced the fuse and all my issues have gone away. I hope if anyone else is having similar issues they find this thread, checking that fuse earlier would have saved a lot of grief.
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Thanks for the resolution!
"I've reset the timing and the car seems to only run with the injection pump advanced off the chart" If this is still the case, the cam and crank may not be aligned (teeth off)
 

Momentslater

Well-known member
Joined
Feb 2, 2018
Location
Calgary, AB, Canada
TDI
2003 Jetta 390k km
Thanks for the resolution!
"I've reset the timing and the car seems to only run with the injection pump advanced off the chart" If this is still the case, the cam and crank may not be aligned (teeth off)
When power failed to the N108 valve I was under full throttle so I think it might have locked the valve in the most advanced position or most retarded. Honestly not sure but replacing the fuse solved my issue, fine tuned my IP timing and have had no issues.
 
Last edited:

Tdiguy89

Member
Joined
Mar 2, 2021
Location
Western nc
TDI
01 beetle alh 5mt, 02 jetta alh 5mt 12 jetta sportwagen cjaa dsg, 13 A3 cbea dsg
Long shot.
With the car running, light and AC on:
Measure the voltage from the negative post of the battery to the case of the transmission, then to a body ground near the headlight.
I would not want to see more then a few tenths of a volt.

If the ground under the battery is bad then anything that grounds to the body is bad.

Last, the message "Short to Ground" may mean no power.
I have not been able to confirm this.
[Saturday?
This saved me bookoo money today. 2001 NB alh. Thank you!
 

Nevada_TDI

Top Post Dawg
Joined
Aug 17, 2008
Location
Reno, sort of...
TDI
2001 Jetta TDI
I'm looking for some advice on the issues I'm having with my car right now. Was driving away from a light and at about 50kmh the car just fell on its face, the car was running really rough and had 4 codes when I checked the car when I got home:

16629: N75 Short to Ground
16486: MAF signal too low
16600: N108 Circuit Malfunction
17068: Glow Plug Control Module (J179) impassable signal

I've reset the timing and the car seems to only run with the injection pump advanced off the chart. Nothing changes when I unplug the MAF and I've put in a known good N75 with no change there as well.

No clue what to be looking for here, kinda lost. Any advice is greatly appreciated!

Please check fuse #34 and if that fuse is blown now you have a place to start, one way is to isolate the ground and shorts. Unplug all of the solenoids on the fire wall and see if you still get the short to ground, then you will know it is the wiring. wiggle the wiring a bit to see what happens. Years ago I had basically the same problem as you do now, the difference is now I know about fuse #34. I purchased a N75, MAF, and few other parts as well. the wiring coming out of the firewall is very small and hard to keep protected from. At present I have the N75, the vacuum ball, a one way check valve, and the turbo, that is all; it is very simple to find problems if they arise.
 
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