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Passat 02 AWM 1.8 T Manual Cruise Troubleshooting

1K views 10 replies 3 participants last post by  Tomvw 
#1 ·
Hello,

I am trying to troubleshoot my cruise control not working on my 02 AWM 1.8 T manual Passat.

Here are the facts:

1. Cruise light comes on when cruise engaged.

2. About the same time I noticed the cruise malfunction, I also noticed an unusual behavior of the car when shifting gear: a sudden acceleration. This phenomenon is not very consistent.

3. I removed the clutch switch and tested for continuity: with switch depressed it reads 0.2 Ohm.

4. I tested switch for leaks (switch depressed and blowing) and I could not detect any.

5. The top contact part of the switch (white button) was broken and missing.

The thing that puzzle me the most is the absence of a "vacuum line". I have read various posts on this blog and others and everyone talks about "vacuum lines" connected to the clutch and brake switches.
To my surprise, when I removed the old switch no vacuum line was attached to the switch and after very careful inspection of the area I could not detect any vacuum lines.

I do know that the CC system varies depending on the car year and engine code, but I thought that all models had the vacuum line on the switches.

Am I missing to locate the vacuum line?

Any suggestions greatly appreciated.
 
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#2 ·
On the old AEB system, the throttle is cable operated and the cruise system actuates it with a vacuum diaphragm driven by a vacuum pump. The switches on the pedals have an electrical switch that shuts down the cruise electrically and also a mechanical vacuum vent that releases vacuum in the system. When the vacuum is vented, the throttle is released.

The newer cars with drive by wire use the DBW capabilities to do the throttle control for the cruise system. There is no vacuum diaphragm. No vacuum controls to vent.
 
#7 ·
Update CC troubleshooting:

Replaced clutch switch (used one). Tested switches with VCDS.

Results:

I) Cruise off - switch position I (brake switch) reading 1100 (pedal off); 1111 (pedal engaged). Switch position II (clutch) 0000 (pedal off); 0000 (pedal engaged)

II) Cruise on - switch position I (brake switch) reading 1100 (pedal off); 1111 (pedal engaged). Switch position II (clutch) 0011 (pedal off); 0011 (pedal engaged)

Any suggestions?
 
#8 ·
After further testing with the VCDS, the following were the readings:

Cruise OFF

Switch position 1: 00001100 brake off
00001110 slightly depressed brake
00001111 all the way depressed brake

The same when pressing on clutch pedal (no change)

Switch position 2: 00000000

The same when pressing on clutch pedal



Cruise ON


Switch position 1: 00001100 brake off
00001110 sligthly depressed brake
00001111 all the way depressed brake

Switch position 2: 00000011
Push Set 00000111
Push Res 00001011
Push Cancel 00000001

The same when pushing clutch


From my limited understanding, it seems that the problem lies with the clutch switch, however this a second clutch switch I just installed...

Does anyone have any suggestions?

Thank you
 
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