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Hello
Ok I am not very mechanically or electrically minded, but love my 993 4s and wanted to repair some of its problems myself.
The Cruise control stopped working 1 month after purchase. So last week, I decided to tackle the problem after reading all the posts on it here and on the net.
Having removed the front seat and the front lining to get at the pedal switches, (long journey, already posted on), I was confronted with an immovable metal plate covering the switches under the seat. There were 2 swithces both black, one bigger than the other. I did manage to disconnected both
I presume the bigger one goes to the cpu unit also installed under the seat?
So with the voltmeter set to 20v I started to measure...
from the circuit diagram
1. Connected to power
2. ?
3. Off AUS
4. BE
5. Driver clutch Driver CC
6. Switch CC wi
7. Driver CC M+ DriverCC
8. Stop Light swithch
9. Poti A Driver CC
10. M- Driver CC
11. Speedometer
12. GROUND
13 Driver CC PositionS
14. Switch Clutch
I have checked the fuse(19 and break lights work)
I presume all Driver CC are the connections to the CC stack on the driving wheel.
I presumed that I would measure the voltage in each slot with power on and Off and break pedal or clutch applied to see if there are any changes in reading in slot 14 and 8 and this would tell me if there was a problem with the clutch or break switch? But could someone explain this to me in detail?
Also another problem since doing all this is that the car wont start. the battery reads fully charge, And the engine turns but does not start? I did try to start the cat with the big junction box disconnected at first, which it did not like??
As for your driver side you are looking at the ECU and the immobilizer. You can remove that sheet metal covering those bits by using a drill and drilling some holes into those bronze looking bolts with no way to remove them with a tool that hold the cover and then some bolt extractors to twist it off.
Ok I came to that conclusion with respect to the metal cover...
The CC unit is on the passanger side... OH Cr*p..
I have to start all over...
Once I get there do you know how to go about trouble shooting it?
Have you disconnected the battery and reconnected it to reboot the controllers. I would do this before getting any more invasive on the cruise control. On our cars, it seems to be a very robust system.
The cruise control switches in the stalk are easily tested by removing the left and right steering column covers. On the right side where the column goes into the dash, the plug for the stalk assembly is tucked in. One can pull it out and check the stalk switch through its plug with a volt-ohm meter. The only other dynamic part is where the system connects to the throttle body, have not worked on this on a 993. These two items other than the stop light switch are probably the only dynamic items subject to physical ware-out. Good news is a used controller on eBay seems to only be $70.
Have you disconnected the battery and reconnected it to reboot the controllers. I would do this before getting any more invasive on the cruise control. On our cars, it seems to be a very robust system.
The cruise control switches in the stalk are easily tested by removing the left and right steering column covers. On the right side where the column goes into the dash, the plug for the stalk assembly is tucked in. One can pull it out and check the stalk switch through its plug with a volt-ohm meter. The only other dynamic part is where the system connects to the throttle body, have not worked on this on a 993. These two items other than the stop light switch are probably the only dynamic items
subject to physical ware-out. Good news is a used controller on eBay seems to only be $70.
yes i am psychologically preparing myself for that. But first i want to check the voltage to the box under the passanger seat. Anyone know how to go about it with the voltmeter as i have not found any detailed explanation for rookies like me.
i want to check the voltage to the box under the passanger seat..
Here are the color codes for the various wires attached to the controller, you will need a fuller set of elecrical drawings to identify which ones provide +Power, grounds are generally brown wires in our cars.
Here are the color codes for the various wires attached to the controller, you will need a fuller set of elecrical drawings to identify which ones provide +Power, grounds are generally brown wires in our cars.
So I know 1 is the power supply, 12 the ground, 14 clutch sensor and 8 the break sensor.... where do i go from there?
The Cruise control is now working and it was the clutch sensor which was not being pushed back enough by the clutch to make contact. It was not that the clutch was hanging, just that the metal bit attached to the sensory was not traveling back enough to make contact. Had another beer after that, and thanks to all in the forum present and past who have explained this problem.
I would add that I diagnosed this the hard way....having removed the driver seat to find the connections to the Cruise control, I was enlightened by samurai_k (thank you for correcting Rookie mistake) That the cruise control is under the passenger seat... and in fact does not need seat removal...after waiting a week for a new bolt which I had destroyed removing the driver seat, I replaced the driver seat and set about testing the electrical supply to the cruise control unit. By putting the voltmeter negative on earth (12) and the red probe on clutch port number (14) I realized that the voltage only changed when I manually moved the metal bit of the clutch sensory further back than the clutch did itself....
05-05-2019, 06:05 AM
Oh Dear...Cruise control trouble shoot
and in fact does not need seat removal...after waiting a week for a new bolt which I had destroyed removing the driver seat, I replaced the driver seat and set about testing the electrical supply to the cruise control unit. By putting the voltmeter negative on earth (12) and the red probe on clutch port number (14) I realized that the voltage only changed when I manually moved the metal bit of the clutch sensory further back than the clutch did itself....