Intermitant Cruise Control
#1
Intermitant Cruise Control
I am still trying to sort this thing out. It was working for a while, but quit again. I need some expert help before I take the steering wheel off.
There are two circuit wires and a ground from the cassette. The circuit wires are s/r and s/g and go to connecter 10 of the ECM. With power on I read line voltage at both pins whether cruise control is on or off. When I disconnect the battery and pull the connecter there is no continuity between the two pins when I press the set button. Am I oversimplifying The function of the buttons? Or is the problem in the button or cassette wiring?
RJ ________________
97 XK8 85K mi
There are two circuit wires and a ground from the cassette. The circuit wires are s/r and s/g and go to connecter 10 of the ECM. With power on I read line voltage at both pins whether cruise control is on or off. When I disconnect the battery and pull the connecter there is no continuity between the two pins when I press the set button. Am I oversimplifying The function of the buttons? Or is the problem in the button or cassette wiring?
RJ ________________
97 XK8 85K mi
#2
#3
I am still trying to sort this thing out. It was working for a while, but quit again. I need some expert help before I take the steering wheel off.
There are two circuit wires and a ground from the cassette. The circuit wires are s/r and s/g and go to connecter 10 of the ECM. With power on I read line voltage at both pins whether cruise control is on or off. When I disconnect the battery and pull the connecter there is no continuity between the two pins when I press the set button. Am I oversimplifying The function of the buttons? Or is the problem in the button or cassette wiring?
RJ ________________
97 XK8 85K mi
There are two circuit wires and a ground from the cassette. The circuit wires are s/r and s/g and go to connecter 10 of the ECM. With power on I read line voltage at both pins whether cruise control is on or off. When I disconnect the battery and pull the connecter there is no continuity between the two pins when I press the set button. Am I oversimplifying The function of the buttons? Or is the problem in the button or cassette wiring?
RJ ________________
97 XK8 85K mi
The behavior you describe is expected.
While disconnected measure the resistance as follows:
BO to SR, Set- should be 680 ohms when pressed, Set+ should be 430 ohms when pressed.
BO to SG, Cancel should be 680 ohms when pressed, Resume should be 430 ohms when pressed.
Check that you have a good ground on BO.
If all that checks out your problem is not with the clockspring cassette or steering buttons.
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#8
The control buttons and cassette check out, but still no cruise control. I can read the power on/off at the ECM so the console switch is working. In fact, everything is working as it should right to the ECM. Could it be that there is no input to the throttle from the ECM?
I do not look forward to a six hour trip without cruise control, I'm getting too old for that.
RJ
I do not look forward to a six hour trip without cruise control, I'm getting too old for that.
RJ
#9
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RJ237 (08-03-2012)
#11
#12
I have looked through JTIS 310-03 and I have already performed the majority of the tests. I will have to set up a plan to go through all of them. What bothers me about the JTIS is that my Autoenginuity software should display a P code if any of those faults have occurred, but I don't have any codes. When I go to the dealer to get a spare key next week I'll ask them to check.
RJ
RJ
#13
#14
Please let me know where the solenoid is as well. I have an intermittent in cruise control as well and I was suspecting the vacuum to the throttle body.
#15
Just take the liner out of the right front wheel well. All three solenoids are towards the rear. Test the solenoids by removing the plugs and applying batt. voltage. I removed them from the car and used my trickle charger with a couple of test leads.
Unfortunately, mine all work, so I need to look elsewhere. I'm still not sure if I have vacuum at the throttlebody switch so I'll check that tomorrow.
Unfortunately, mine all work, so I need to look elsewhere. I'm still not sure if I have vacuum at the throttlebody switch so I'll check that tomorrow.
#16
I decided to check the vacuum system. By running a tube into the passenger compartment from the fitting that slips on the vacuum control on the throttle body I was able to determine that there is no vacuum. In fact, I was able to suck air through the tube. I then determined that there was line voltage to all three solenoids from the ECU when the ignition is on.
Confusing- There was vacuum in the accumulators next to the solenoids, the solenoids all work when bench tested, there is power to the solenoids when the ignition is on. I'm missing something.
RJ
Confusing- There was vacuum in the accumulators next to the solenoids, the solenoids all work when bench tested, there is power to the solenoids when the ignition is on. I'm missing something.
RJ
#17
I decided to check the vacuum system. By running a tube into the passenger compartment from the fitting that slips on the vacuum control on the throttle body I was able to determine that there is no vacuum. In fact, I was able to suck air through the tube. I then determined that there was line voltage to all three solenoids from the ECU when the ignition is on.
Confusing- There was vacuum in the accumulators next to the solenoids, the solenoids all work when bench tested, there is power to the solenoids when the ignition is on. I'm missing something.
RJ
Confusing- There was vacuum in the accumulators next to the solenoids, the solenoids all work when bench tested, there is power to the solenoids when the ignition is on. I'm missing something.
RJ
Just a thought.......
#18
No, I'm using Autoenginuity and can read P codes. Also, I have repeatedly checked pin EM10-11 on the ECM which receives power after the brake switch/cruise control switch. That doesn't eliminate the possibility that not enough current is available to activate the vacuum solenoids, but I don't think there is much chance of that being the case. maybe I'll try bypassing both switches and see what happens.
RJ______________
97 XK8 85K mi
RJ______________
97 XK8 85K mi
#19
No, I'm using Autoenginuity and can read P codes. Also, I have repeatedly checked pin EM10-11 on the ECM which receives power after the brake switch/cruise control switch. That doesn't eliminate the possibility that not enough current is available to activate the vacuum solenoids, but I don't think there is much chance of that being the case. maybe I'll try bypassing both switches and see what happens.
RJ______________
97 XK8 85K mi
RJ______________
97 XK8 85K mi
Cheers,
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RJ237 (08-06-2012)
#20
I checked the voltage at the three solenoids today. Two of them are grounded through the engine management fuse box and read 0 V with the power and CC on. The third is grounded directly and reads 9.1V. This one appears to be the control for the CC vacuum and maybe the voltage increases when the CC is operating, but 9.1V is not enough to open the valve. I have buttoned everything up and resigned myself to waiting until I get to the dealer and see if they can sort it out without replacing everything.