GRA temporarily defective

@all,

I have a Passat Variant (V6 Syncro, 193 hp, first registration 12/98, 240,000 km) that came with a factory-installed cruise control system (GRA - Geschwindigkeitsregelanlage).

'For some time now, the GRA has been intermittently failing. It also doesn't work during longer trips. However, on the next trip, it might start working again.'

When the GRA (Ground Radar Altimeter) is functioning correctly, you can hear a faint clicking sound, similar to that of a relay, when it is activated.
If it doesn't work, you don't hear anything. Then, the power button, the accelerator, and the ignition won't work either.

What could it be? The lever? The relay? Is there a control unit? Could a switch on the clutch or brake be defective ('stuck')?

The car was just taken for an inspection. The printout from the error memory shows nothing. Or is it possible to only read out a portion of the error memory?

I had asked the workshop to check the GRA (Gear Range Analyzer). They said the steering column lever was defective. However, when I picked up the car, the GRA was working again. Later, it started failing intermittently.

I'm always skeptical when the repair shop immediately wants to replace something.

Is anyone else experiencing this issue?

Sure, no problem.

Greetings.
Peter.

Hello,

Take a look at the switch located on the clutch pedal or the brake pedal...

Hello,

Take a look at the switch near the clutch pedal or the brake pedal.....

Thank you for the tip!

I've also suspected something along those lines. However, I'm not sure where the switches are located (they're definitely not visible on the clutch and brake pedals), and I'm not sure how to test them.

Greetings.
Peter.

Well,

I'm not exactly familiar with your car, but in mine, I can check the switch position using VCDS.
"Read out the data (but not from the error memory). Of course, it's not easy when the error is intermittent. I don't remember exactly which measurement block it's in, but the switches must be mechanically connected to the pedal somewhere... otherwise, where would they be?"
I once had a similar problem. What helped was tapping the clutch pedal a few times.
If the problem reappears, try simply tapping on one of the pedals, which should cause the corresponding switch to activate. If that helps, you can narrow down the source of the problem.

Hello.

I just received this error message a moment ago, after an inspection.

On Friday, I went to the . I took my car to the garage for an inspection.
At that time, the GRA was still working perfectly.
I picked up the car, and on the way home, the advertisement confirmed that...
I turned on the GRA, but I can't set the speed.

Not that would reset the GRA for me in the inspection report.
has been programmed out!

I will show up directly at the tomorrow morning.

It was a pretty strange inspection!

- The windshield wipers are almost new and in perfect condition (and were not mentioned as having any issues).
A piece of rubber was hanging down when I started driving!!!
-Supposedly, the valve cover gasket is leaking. ( wanted to schedule an appointment right away).
I checked it myself . Everything is perfectly sealed!!!

If a VAG Com diagnostic tool is not available, remove the lower trim panel (the part that runs horizontally from the pedals to the visible part of the dashboard) and check the switches located above it. The brake switch is a double switch, while the clutch switch is a single switch. In general, this is the only potential source of the problem that can be identified without a VAG Com tool.

It might still be in the "off" position at the switch, but in that case, the green indicator light shouldn't be on either. This can also be checked with VAG-COM.

Hello Perly,

"I also had this problem with my Passat and searched for a long time. Checking the switches didn't help. I could activate the cruise control, but it would always turn off after a short time. The solution turned out to be a bad ground connection in the taillight. When the turn signal was activated, the positive voltage was sent to the brake light bulb, which in turn triggered the cruise control to shut off."

I'd call that a really interesting bug – does the cruise control always turn off when you use the turn signals?

Yes, that's exactly what happened. Initially, the problem occurred intermittently when a trailer was attached, but then it also started happening without a trailer. It's important to know that the entire grounding connection for the taillights, as well as the connection for the trailer socket, runs through a connector in the left taillight. This connector likely became very hot due to the constant load, which damaged the surface protection and caused it to corrode. After I fixed the problem, the cruise control also started working again.

Best regards,
Benno.

@Benno,

That is quite interesting.

But how did you find the error? You can't possibly check all the ground connections, can you? And most importantly, you must have had some idea of what was causing the problem.

My light for the LIMA started working four months ago, and the battery no longer charges.

My dealer installed a new LIMA for me .

I've also heard that this issue can occur due to a poor ground connection. That wouldn't have been a profitable situation for the workshop.

Two years ago, I had a problem with my Climatronic system.
Several workshops initially wanted to replace the control unit and then the evaporator (which would cost around €2000.00 in total). The problem was a faulty connector connection to the pressure sensor of the air conditioning system.

However, that requires a systematic search process, which unfortunately overwhelms many workshops today.

Greetings.
Peter.

Hello Peter,
While driving with a trailer and the lights turned on, the turn signals stopped working properly. I initially suspected the socket, as I had experienced problems with it in other cars before. However, the socket itself was fine. While tracing the ground wire, I eventually found the source of the problem.

Regards,
Benno.