Thread: Cruise control

No, there's just the light on the switch itself.

If you know anyone else with a similar year P38 nearby you could borrow their ecu for a test drive to prove whether yours is at fault or not. They're very easy to get at and replace/swap (on my '95 it is anyways)

OK, update. I bought a used Cruise ECU and inverter from EBAY UK and installed it went for a run and.... no luck. Still no clicking relays and my initial diag using the ETM in RAVE appears unchanged. I am not getting a speed signal from the BECM to the cruise ECU. (Which results in the flowchart pointing to the BECM or the wire from BECM to Cruise ECU, checked wire, not broken). I am aware the BECM is getting a signal from the ABS ECU, checked this with meter. I am also aware using faultmate that all the other ECU's that have a speed input are receiving their signal from the BECM. Anyone know of anywhere in Sydney that are any good with BECM's?? Or should i just delve in and have a go myself?

Give lee at LAB electronics a call 02 48711218, hes in mittagong and reprograms BECMs while he sleeps. (well sort of....) He is a retired ex landrover mechanic who is in love with the P38 becm.

If He cant help you, and you feel adventurous, I have a cracked spare BECM you could try.

Andy

Ok latest... Took it to Lee as per Andy E's advice, thank you Andy. (Id like to know half of what i imagine Lee has forgotten about P38s...)

As per all the tests in the ETM i had previously carried out, the only one it failed with Lee was also speed signal from BECM to cruise ECU. He'd never seen it before either. So looks like a second hand BECM required.

One thing I am talking to Lee about is if we can piggy back a speed signal heading to another ECU say, EAS, GEMS or HEVAC. If anyone knows anything all ideas welcome....

Ok so update...

Well, i thought I would check my battery leads with the ETM test and it failed dismally. A 1.3 volt drop from Alternator to battery so i replaced my battery leads to the earth points and the alternator and sanded the earth points in the engine bay. ALso replaced the alternator to positive battery lead. All voltages MUCH better after a run. Thought id just give the cruise a try, dunno why i bothered but..... jackpot. Its working again! You bloody beauty! So obviously, the voltage output from the BECM for the cruise ECU requires a healthy 12v for the ABS ecu and BECM to send it with enough err, balls, for the cruise to pick it up. Oh and gee it starts quick now!

So thanks to all for suggestions. Goes to show the importance of those earth points and battery leads many threads talk about. Thanks to Andy E for putting me in touch with Lee too. Top blokes both!

If you ever need a second speed signal output, you can use c255 pin 10 (HEVAC speed signal) as well as pin 20...

Great followup, thanks for articulating your fix. Good on you for sorting it out. This will be valuable to many in the future I imagine.