How often do ALH computers go bad?

faul713

Member
Joined
Aug 11, 2011
Location
Phoenix, Arizona
TDI
2003 Jetta, 2004 Beetle, 2005 Beetle, 2005 Jetta
Sorry, I owe some apologies here. I've been away from the forum for a real long time and just realized I never got back to this post. I was updating my signature and found the old post section which criticized me, and rightly so, for not providing any closure.

I never found out what was wrong. The car is still parked and as soon as I find the key, it will be sold. I found a deal on a 2004 Jetta with 4K miles and bought it.

I am of the opinion the problem is with the injection pump but can't prove it. I had to reseal it multiple times and think it's just wore out. I pulled the ECM and looked inside but found nothing unusual. I have 17 years of electronic engineering experience in a test, development and manufacturing capacity and figured it was worth a shot.
 

Tdijarhead

Top Post Dawg
Joined
Nov 10, 2013
Location
Lawrenceville PA
TDI
2003 TDI Jetta Daughters Car, 2001 TDI Beetle, Daughters car, 2005 Golf TDI Mine, all 5 spds
I never found out what was wrong. The car is still parked and as soon as I find the key, it will be sold. I found a deal on a 2004 Jetta with 4K miles and bought it.
Is this a misprint ? A 2004 with 4 thousand miles? Pictures please, what kind of shape is it in? Where/how did you find such a diamond?
 

Shenandoah

Veteran Member
Joined
Jan 9, 2008
Location
Shenandoah Valley, VA
TDI
2005 Jetta Wagon; 2005 Beetle; 2004 Jetta; 2002 Golf (three of them); 2002 Jetta Wagon; 2000 Audi TT->TDI; 1999 Beetle
Folks,

Not an ALH ECU, but a 2002 Jetta (2.0l gas, automatic). Earlier this year my daughter had transmission problems. I made an adapter to plug in to the transmission connector to check resistance on the solenoids. I had two that were out of range. Replaced them all along with the ribbon cable connector.

Car ran fine and transmission shifted correctly. About a month later it quit driving down the road. Scanned with VCDS but could not find the ecu. I checked all the fuses and relays, cleaned the grounds and still no ecu. I've got four parts cars, so I put in an ecu from a 1.8l Jetta, connected it to the 2002 2.0l and could see it through VCDS. Put the original ECU back in and could not see it with VCDS. Somehow it failed/fried?

Bought another ECU for the same model car and had the immobilizer turned off. I installed the ECU and again, the car ran fine. About two weeks later, same thing: ECU could not be scanned/found with VCDS.

Somewhere there is an electrical problem when under the right conditions, it fries the ECU.

Eric
 

compu_85

Gadget Guy
Joined
Sep 29, 2003
Location
Springfield VA
TDI
... None :S
My no-evidence speculation is that one of the voltage regulators in the ECU is failing. This is what provides the 5v reference to various sensors, and to the chips inside the ECU. Basically, the internal power supply to the ECU.

-J
 

burn_your_money

Veteran Member
Joined
Oct 16, 2012
Location
Missouri
TDI
99 Beetle, 96 B4V, 05 Passat wagon
On the gassers there is an issue with O2 sensors shorting out or something to that effect and it kills the ECU. It’s been a while since I’ve read about that so I may have some details mixed up.
 

faul713

Member
Joined
Aug 11, 2011
Location
Phoenix, Arizona
TDI
2003 Jetta, 2004 Beetle, 2005 Beetle, 2005 Jetta
That was a typo, the car had 64K miles on it. That car is now parked as well. It got rear-ended hard. It was crushed between a large work truck that had one of those bumpers with a vice bolted to it and a 65+ mph minivan with a distracted driver.
 
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