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Discussion Starter #1
I have a new to me P38 with a speedometer and cruise control not working. It started with abs and tc warning lights. They went out after replacing the ABS ECU. It has new front wheel sensors. Using a scope, I was able to see a square wave pattern increasing with speed at the BECM. (eg pin 11 to ground on C1289). I tested all of the pins on C0233 to ground (the connector that plugs into the instrument cluster) but can't find a similar waveform. The Electrical troubleshooting manual doesn't say specifically where to find this signal at the instrument cluster. It says it originates at the wheel sensors and is sent from the ABS ECU to the instrument cluster and other ECUs. The diagram on E1 shows the wheel sensor connections but not the output of that signal as far as I can see. I have found and repaired some wiring issues in the harness. What I really could use help on is specifically where to measure for that signal...
Thanks,
Kevin
 

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1995-2002 Range Rover P38A
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I've only got the old connector numbers for the BECM road speed inputs/ outputs so you'll have to do a bit of cross matching but:
Input
C114 #11 YG ABS ECU> BECM
Outputs
C256 #16 Y BECM> Instrument Pack C242 #9
C255 #20 Y BECM> Cruise ECU C243 #11
C112 #13 Y BECM> EAS & ECM ECU C117 #30 and C507 #27
All BECM outputs are shown as sq wave GND to vBatt 8000 pulses/mile typically 2.5v when vehicle moving

Cruise and Instrument panel have a common earth point behind RH footwell trim panel. Might be worth cleaning that as it can get corroded
 

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Thanks for the info! I had already found and cleaned the grounding point you mentioned and will use the other information as a good starting point for locating the test points...
 
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