christmas tree of warning lights

jkedward

New member
Joined
Dec 5, 2017
Location
chapel hill nc
TDI
2014 vw passat tdi
Hello, World.
2014 vw passat tdi se, manual trans. Love the car. Not so much now.
On a trip, the steering-wheel-air-bag warning light, the SRS warning light, the ABS warning light, the (second) airbag warning light, and the low tire pressure warning light all came on. Looks like a christmas tree.
Bought the RossTech vag-com to read the codes...lots of errors pretty much corresponding to the warning lights. I don't believe all those faults could crop up simultaneously, but rather expect something in common to be causing it.
Did some searches, found folks with wet ECU in older passats. ECU in 2014 is between the battery and fuse box, has its' own umbrella, and was completely dry.
Some more searches, found folks with bad ground issues. Traced the ground from the battery to the firewall, found an acorn nut painted body-color-silver with the edges of the nut rounded as if by an idiot with a crescent wrench. I'm certainly qualified to do this maneuver but didn't. Took nut off, added conductive grease to the cable and nut, reassembled. Reset DTC codes, warning lights went off for an hour drive with two stops, came back on after car sat for an hour.
I'm guessing perhaps the battery is getting old (3 years, just barely out of warrenty)? Bad voltage regulator? More grounding issues? I could trace and debug each and every warning, but what are the chances they all pop up simultaneously?
Any suggestions will be appreciated.
 

whitedog

Veteran Member
Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
Hello, World.
2014 vw passat tdi se, manual trans. Love the car. Not so much now.
On a trip, the steering-wheel-air-bag warning light, the SRS warning light, the ABS warning light, the (second) airbag warning light, and the low tire pressure warning light all came on. Looks like a christmas tree.
Bought the RossTech vag-com to read the codes...lots of errors pretty much corresponding to the warning lights. I don't believe all those faults could crop up simultaneously, but rather expect something in common to be causing it.
Did some searches, found folks with wet ECU in older passats. ECU in 2014 is between the battery and fuse box, has its' own umbrella, and was completely dry.
Some more searches, found folks with bad ground issues. Traced the ground from the battery to the firewall, found an acorn nut painted body-color-silver with the edges of the nut rounded as if by an idiot with a crescent wrench. I'm certainly qualified to do this maneuver but didn't. Took nut off, added conductive grease to the cable and nut, reassembled. Reset DTC codes, warning lights went off for an hour drive with two stops, came back on after car sat for an hour.
I'm guessing perhaps the battery is getting old (3 years, just barely out of warrenty)? Bad voltage regulator? More grounding issues? I could trace and debug each and every warning, but what are the chances they all pop up simultaneously?
Any suggestions will be appreciated.
It's your car wishing you a happy Christmas.

What is the description of the codes? Is it over voltage? Undervoltage? Short to power/ground? The description will help you focus your troubleshooting.
 

tdiatlast

Top Post Dawg
Joined
Jan 21, 2009
Location
Fort Worth, Texas
TDI
2009 Sportwagen (boughtback); 2014 Passat TDI SEL (boughtback)
Start with the battery...cheap...and yes, 3 years is about average. I recommend OEM, from a dealer, cost is okay, and warranty is good, too.
 

jck66

Top Post Dawg
Joined
Jan 4, 2001
Location
Greenwich, CT, USA
TDI
12 Passat SE / 14 BMW 535d
Agree on the battery as a place to start. The battery is easy and not too expensive - the OEM unit on my 2012 died a sudden and unexpected death at 3.5 years or so. No exciting warning lights in my case, just a complete and total lack of enthusiasm one morning.

Next look for grounding issues as you mentioned! Good luck.
 

thundershorts

Top Post Dawg
Joined
Jul 15, 2010
Location
west chester pa
TDI
2015 passat tdi sel premium 2015 golf s tdi gls tdi b5.5, 2002 eurovan,Peugeot 505 td,Citroen cx25 prestige
the batteries the VW dealers offer are pretty decent and most offer a fair discount.
 

jjblbi

Veteran Member
Joined
Sep 27, 2000
Location
lbi, nj
TDI
2014 Passat SEL TDI
Have you cleaned the battery connections and battery to body ground connection. Battery load test should also indicate battery condition.
 

06bluebeetletdi

Veteran Member
Joined
Sep 30, 2012
Location
Middlesex, NC
TDI
'14 Passat TDI SEL and '13 Beetle TDI
If the lights came on while driving, it could be a wheel speed sensor, battery would have the lights come on at inital start then go off after a little driving.
 
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