Cruise control failure, Engine light

[stevedee3]

Hi everyone,

I've had a recurring niggle with my cruise control. The problem is that it won't engage, but then several minutes later it works as if nothing was ever wrong.

Here's what I've done so far:

1. Took it to dealer, a fault code had been logged. They replaced the CIM module and stalk.
2. Same fault again, this time dealer reported no fault diagnosable. Dealer produced a service document pointing out that the brake must be activated at least once after the ignition is activated before cruise control can be activated. (Safety feature I guess). This is not documented in the manual, but it also doesn't explain my problem, since I'm certain I'd used the brakes before trying to use the cruise control.
3. Engine/immobiliser warning light randomly coming on for several seconds at a time. No apparent effect on driveability or ability to start the car. Now the spanner comes up for a few seconds each time the car is started. Took the car to Holden who scratched their heads, saying they couldn't tell why the light was coming on, but they "reset everything". They claim that no fault codes were stored, but I find this a bit implausible. Surely the engine ECU wouldn't be displaying warning lights with no fault codes to back them up?
4. The spanner icon's coming on again now. It's booked in at Holden again tomorrow.

I'm not sure whether the spanner icon and my cruise control problems are related or not, but it does seem to be a bit of a co-incidence. Does anyone have any bright ideas on what might be going on? I'm not very optimistic that this dealer is going to be able to diagnose/fix this problem tomorrow...

[Damian]

I had a problem in my last Vectra C with the cruise control not engaging, and the way to resolve was to put my foot under the clutch and brake pedal and ensure they were all the way up, then the cruise control would engage.

Because as I am sure you are aware pressing the clutch or brake disengages it. It wouldn't explain your dash light that is coming on, but might explain the intermittant fault with the cruise control and why the dealer can't resolve it

Damian

[stevedee3]

I had a problem in my last Vectra C with the cruise control not engaging, and the way to resolve was to put my foot under the clutch and brake pedal and ensure they were all the way up, then the cruise control would engage.

Because as I am sure you are aware pressing the clutch or brake disengages it. It wouldn't explain your dash light that is coming on, but might explain the intermittant fault with the cruise control and why the dealer can't resolve it

Damian

Thanks @Damian.

If (when?) it happens again I'll give that a try. I tried pressing both pedals but I never thought of lifting them. The brake switch is nice and easy to diagnose, since you can just check the brake lights. The clutch switch is a bit trickier since AFAIK nothing else but the cruise control uses the clutch switch.

[GARY3306]

I had a problem in my last Vectra C with the cruise control not engaging, and the way to resolve was to put my foot under the clutch and brake pedal and ensure they were all the way up, then the cruise control would engage.

Because as I am sure you are aware pressing the clutch or brake disengages it. It wouldn't explain your dash light that is coming on, but might explain the intermittant fault with the cruise control and why the dealer can't resolve it

Damian

That's exactly what I did with mine. It only takes you to barely rest your foot on the brake/clutch pedal and it knocks the CC off, so with that in mind I pulled tyhe pedals up with my foot, tried again and it worked fine. That was about 6 months ago and I have had no bother since.

[james.stoogies]

there is a known fault with the vectra C and Signum clutch pedal return spring. the spring breaks and the fault you describe is a common complaint from drivers. Originally Vauxhall replaced the complete pedal box assembly which meant removing the dash and some of the interior. They came up with a feild remedy which involves fitting a over centre spring which sorts the problem. If their is movement of about half an inch freeplay in the clutch pedal go and see your dealer and ask them to carry out the rework.

[stevedee3]

there is a known fault with the vectra C and Signum clutch pedal return spring. the spring breaks and the fault you describe is a common complaint from drivers. Originally Vauxhall replaced the complete pedal box assembly which meant removing the dash and some of the interior. They came up with a feild remedy which involves fitting a over centre spring which sorts the problem. If their is movement of about half an inch freeplay in the clutch pedal go and see your dealer and ask them to carry out the rework.

Thanks @james.stoogies, I'll have to check that out.

The spanner light was apparently a history code, something to do with "frist stage radiator fan" or something like that. Doesn't sound like it's related to cruise control. Perhaps I have two problems...