03 jetta ALH weird limp mode issue

[TDIWAY]

i have a friend/customer who has an 03 alh, and the biggest issue is i cant get his car long enough to do some thorough diagnostics, his car has 425,00km on it, he started complaining of CEL light on, and glow plug light flashing and intermittent loss of power, he can pull it over shut off and restart and drive for awhile again, i hooked my VAG-com up and pulled some codes, i dont remeber the numbers write off its been a little bit, but there was a brake light switch code set, a throttle position code, and all 4 glow plugs, so for kicks i checked all for glow plugs, i believe 3 of the 4 were burnt out, i replaced all 4, i also fixed some chaffed wires close to the tps i believe, cleared codes, problem still exists, so i check and repair all brake lights, install a new brake light switch and cleared codes, while i had vehicle the brake light switch code and tps code stayed off, but glow plug 2 and 3 wiring codes were set, he needed his car that night drove it a few miles glow plug light flashes and he got into limp mode again, im sorry for the lengthy post just trying to get as much info as possible, and next time i get him in i will record all the codes stored, i have not had enough time yet to check into the maf and some other limp mode issues so i just thought i would see what some of you guys thought

thanks

 

[TDIWAY]

Im still having an issure with this car i am pretty lost if anybody has had something similar id love to hear

thanks

 

[phawkins224]

flashing glow plug light could be several issues...brake light switch, a brake light thats out, if its a manual could also be the clutch switch...if you have a flashing glow plug and a cel then if could be the IP going bad not limp mode...if you cycle the key off and restart the car does the limp mode go away and then re occur when the car boosts again?

 

[TDIWAY]

yes that seems to be what is happining he can pull it over and fire it up again and its fine for awhile, he says it seems to happen more when he is going slow and on and off the brakes alot, more so than at highway speeds, i have replaced the brake switch and have made sure all bulbs are fine

thanks

 

[phawkins224]

turbo is full of crud.....needs a good cleaning

 

[ecodean]

Intake manifold/EGR clogged, restriction causes irregular boost readings hence computer puts it into limp mode.

 

[phawkins224]

Have you hooked a mighty vac to the acuator on the turbo to test the vanes to see if it moves freely...

 

[dr64ml68]

yes that seems to be what is happining he can pull it over and fire it up again and its fine for awhile, he says it seems to happen more when he is going slow and on and off the brakes alot, more so than at highway speeds, i have replaced the brake switch and have made sure all bulbs are fine

thanks

I had the same issue with my 03 Jetta. Except after a longer wait I could drive it for about 1/4 to 1/2 a mile before it would stall again but would only run in limp mode. I found the crankshaft position sensor bad. Replaced it, drove about 15-20 miles in limp mode, CEL light went out and engine ran normal. Running better now than it was, actually. Hope this helps.

 

[RacerTodd]

Per a post by MoGolf, the codes that cause a flashing glow plug light are below. I've twice had a flashing glow plug light only to find that VCDS shows no codes saved anywhere. Go figure.

00741 Brake pedal monitoring - implausible signal
01044 Control unit incorrectly coded
16705/P0321 Engine speed sensor - implausible signal
16706/P0322 Engine speed sensor - no signal
16955/P0571 Brake light switch (F) - implausible signal
17653/P1245 Needle lift sender (G80) - short to earth
17654/P1246 Needle lift sender (G80) - Implausible signal
17655/P1247 Needle lift sender (G80) - Open circuit/short to positive
17762/P1354 Modulating piston movement sender (G149) - electrical fault in current circuit
17969/P1561 Metering adjuster (N146) - control difference
17978/P1570 Engine control unit blocked
18020/P1612 Control unit incorrectly coded
18026/P1618 Glow plug relay (J52) - short to positive
18027/P1619 Glow plug relay (J52) - open circuit/short to earth
18040/P1632 Accelerator position sender - voltage supply