[dionysum]

Hi all,

I have a 2002 Golf TDI that has been acting a little twitchy. Sometime this winter, I started occasionally having my ABS and brake lights flash, but with no symptoms of either malfunctioning. It wouldn't happen every time I started the car, seemed to mostly be on the coldest days.

Some weeks later my engine light came on - code was for glow plugs, which I replaced last week. Since replacing the plugs, the ABS/brake light flash has been consistent for the first 5 minutes or so after every cold start. I drive 40+ miles one way for work, so I see that the lights stop and don't come back on. For what it's worth, this now happens on every cold start (regardless of outside temperature), but does not seem to happen if I restart once the car is warm.

Using VCDS I get an ABS code
00668 - Supply Voltage Terminal 30
008 - Implausible Signal - Intermittent

I was thinking I need to replace an ABS sensor, but the two electrical problems seem related to my uninformed mind - especially since the ABS issue seems to stop when the engine is warm enough for the glow plugs to stop working.

I checked the fuse box a while back and didn't notice anything obviously wrong, but could still be an issue. If it is a ABS wheel sensor (front) how do figure out left or right?

Thoughts on how to proceed?

Thanks

 

[chittychittybangbang]

Check the fuse box above the battery. There are a bunch of big fuses in there,. look for melted plastic or corroded connectors. You could also try unplugging-replugging the ABS module. It's on the driver's side under the air box area. It's possible a connection there or at the abs sensor harness is bad.

Also, has the brake light switch ever been replaced? I think it should cause a brake sensor code but these have also been a problem area and was recalled a few times.

 

[Keithuk]

You can check the waveforms/signals coming from all ABS sensors with VCDS in measuring blocks. Get someone else to operate the laptop while you are driving.

EOBD II Error Code: 00668

Fault Location:
Supply Voltage Terminal 30: Signal Outside Specifications, Implausible Signal

Possible Cause:
Fuse(s) faulty.
Wiring/Connectors from/to Control Module faulty.
Power Supply (Battery/Generator) faulty.

Possible Solutions:
Check Fuse(s).
Check/Repair Wiring/Connectors from/to Control Module.
Check Power Supply (Battery/Generator).

Special Notes:
When found in an individual control module, it's most likely a local source (e.g. wiring/connectors).
When found in multiple control modules at the same time, it's most likely a common source (e.g. ground spot, battery, generator).
Intermittent codes are often stored during low outside temperature when the battery capacity goes down and may be ignored.

As taken from my http://www.myturbodiesel.com/forum/f9/free-eobd-ii-error-codes-software-2919/

 

[Seatman]

When I had a faulty sensor it came up with a code for that specific sensor, it sounds like you're having a different issue, need to check the supply voltage I reckon.

 

[dionysum]

The fuses looked good overall. I unplugged and replugged everything and it seems to be working okay now so I guess something was loose. Hopefully I won't be posting again in a month saying "it's doing it again and I had to reconnect everything again."

Thanks for the help and suggestions!