Member Since: 16 Aug 2016
Location: South Northants/Oxfordshire
Posts: 216
Robbie, any recommendations to sourcing one?
11th Jan 2017 9:02 pm
TinTapper
Member Since: 16 Aug 2016
Location: South Northants/Oxfordshire
Posts: 216
Stuck the multimeter back on circulating pump and got the required 10K ohms (might have selected wrong setting on multimeter the other night )
So I put power to pump and away it went! So is the FBH output giving me the short circuit fault? That would be the PCB I guess??
Any ideas??
Last edited by TinTapper on 15th Jan 2017 11:56 am. Edited 1 time in total
13th Jan 2017 5:58 pm
TinTapper
Member Since: 16 Aug 2016
Location: South Northants/Oxfordshire
Posts: 216
Another day fighting the FBH problem
Took unit off car again, checked all internal wiring for any visual clues...
Checked circulating pump - all working.
Fitted it all back, ran WTT diagnostics - even when the circulating pump is disconnected it shows 'short to earth' on pump circuit, so is it the FBH unit itself?
14th Jan 2017 6:10 pm
TinTapper
Member Since: 16 Aug 2016
Location: South Northants/Oxfordshire
Posts: 216
Anyone got a spare PCB for V Top??
16th Jan 2017 10:55 am
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
If you send your old one to me I will test it and see if it is fixable.Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 16 Aug 2016
Location: South Northants/Oxfordshire
Posts: 216
16th Jan 2017 1:43 pm
Gazellio
Member Since: 08 Jan 2011
Location: Chilterns
Posts: 4130
I note there are several used/breaker yard units for sale around £100 on ebay...
16th Jan 2017 1:53 pm
TinTapper
Member Since: 16 Aug 2016
Location: South Northants/Oxfordshire
Posts: 216
Yes, I had a search. Several about but really wanted my PCB checked first - had a look online at PCB repairers but would really need a circuit diagram for them.
Then Rob offered his expertise, so that's a good place to start...
Think many of us have been there before - buying up parts until you fix the job only to find it's cost the same as a new one
The gamble does pay off sometimes I admit! Electronics are also a sod sometimes...
My Dad can't understand why I want to fix the under bonnet bonfire
16th Jan 2017 3:50 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
The postie brought me the FBH ECU this afternoon so wired it to the test setup. The circulation pump fault was the only stored fault code and clearly everything was working until this fault. The unit draws normal current and communicated normally over WBUS:
Click image to enlarge
The FBH does not lock-out with a circulation pump short circuit fault, at least on this version. With no pump connected the fault will clear and show no faults until the pump is connected and commanded to run.
Click image to enlarge
The control unit puts around 2.3v on the pump circuit when connected and in standby, which this ECU did. When the pump is commanded on it receives full system voltage but the output from this ECU just collapsed back to 2.3v after a brief voltage flicker and stored the 'short' fault:
Click image to enlarge
A healthy ECU pump voltage on a different FBH when commanded to run:
Click image to enlarge
So a confirmed dead ECU board. The PCB had no visible issues and apart from the pump run voltage all the pinpoint tests checked out fine, so I am unsure of the exact cause of the failure. I reflowed the usual suspects but it made no difference.
Sorry the news is not better but at least the fault is confirmed.
Land Rover - Turning Drivers into Mechanics Since 1948
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