Planning A Fault diagnoses.. Need some pointers

I was Talkin/posting to Irish before about this Damn Cruise Control Jamming ON....

We reached the conclusion that, well its BROKE & I need to fix it, so,

Heres what I've done Already....

1. Replaced all the Pipes.... STS..( Still The Same)
2. Replaced the Brake Pedal Switch STS
3. Checked the main switch OK ..but STS
4. Adjusted the Cable.....STS
5. Checked the Bellows ...STS
6. Checked the Vac Pump ..OK ..STS

I am rapidly reaching the idea it COULD BE either the Cruise Control Inverter or the Cruise ECU....(Both Relativly cheap to replace) BUT...........

& these are the things I DON'T KNOW (& can't find the answers on RAVE)

1. The cruise ECU get its input from a speed sensor WHERE IS THIS LOCATED??? or does it go thru the BeCM ( same as the Instrument Pack) If so the Speed sensor MUST be OK coz its showing the correct speed on the Dash.
2. What does the INVERTER DO????
   [*]Assuming the Speed sensor is OK & the Inverter is OK that leaves me with the Cruise ECU ..... If I swop it out what will this do to the BeCM??
3. Will it just "Recognise" the "New" Cruise ECU & work normally or will it throw up a Hard Fault & SCREW IT UP COMPLETELY????

I should point out that I have NO FAULTS showing ( Well I do, F-OS sidelight bulb) but thats nowt!! Because its jamming in an "ON" position we can rule out the pipes, Bellows, Vac Pump & to a certain extent the ECU because

• the cruise ECU MUST be getting a feed from the BeCM (otherwise it wouldn't work at all!!)
• The Vac pump MUST work coz it sucked the bellows FLAT!!!( which means the ECU is "Sending" a signal)
• The Bellows can't have a hole in (Coz they STAYED FLAT!!)
• Which brings us nicely back to the speed sensor ( & point 1 above)
• But THAT must be OK coz the instrument readings (Speedo) are working Normally

Final question ...... WHY didn't the Brake pedal switch cancel the cruise when I braked & Why didn't the cruise cancel altogether when I switched off the main Dash switch....( I suspect that this half of the problem is Mechanical..i.e. The bellows just "STUCK" Flat)



AAARRRGGGHHH!!!!!!.... MY HEADS HURTS!!!!!!!!

I think writing THAT LOT^^^^^^ down has made me understand it better
VVVVVVVV This is from Rave VVVVVVVVV

Vacuum pump

When cruise control is active and cruise ECU inputs
are acceptable, the ECU energises the vacuum pump
motor. The vacuum pump creates a vacuum in the
actuator which operates the throttle linkage. When the
required speed has been achieved, the ECU switches
off the vacuum pump. The ECU also controls a dump
valve which allows system vacuum to vent to
atmosphere.

OK I'm going for an ECU fault ...... Forget all that twaddle up there ..Can someone just answer the question in RED please!!!!!


Cheers


Keith

3. Nothing
4. Yes it will recognise it.

If you follow the faultfinding steps on RAVE, you will pinpoint the faulty component.
:behindsofa:

Irishrover said:

3. Nothing
4. Yes it will recognise it.

If you follow the faultfinding steps on RAVE, you will pinpoint the faulty component.
:behindsofa:

Click to expand...

Irish,

Either I'm far THICKER than I thought I was or ...... My Rave copy does NOT have a "Faultfinding" section!!!!!!!!!!!!!!!
Seriously now, can you point me to that section please.....

Cheerrs


Keith

Go to the electrical section on rave/section B5 cruise Control. It's page 67.

:behindsofa:

Irishrover said:

Go to the electrical section on rave/section B5 cruise Control. It's page 67.

:behindsofa:

Click to expand...

Thanks Irish ..................... Ran right thru the Fault diagnoses & Reached test 5D................ WHICH READ ......

RESULTS
Cruise Control Vacuum Pump
Operates


Throttle Opens Wide <<<<<<<<<<<<<<<<< Now THAT I can relate to!!!!
Valve Closes

^^^^^^ That is THE ONLY condition where the throttle opens WIDE


THANK YOU IRISH ...YER A STAR!!!!!

Glad your getting there !!!!

:clap2::clap2::clap2: