The Dispatch | Expert | Scudo Hub

Get help & share your Citroen Dispatch (Jumpy) | Peugeot Expert | Fiat Scudo tips

You are not logged in.

#1 2019-11-25 00:02:13

Tony Jones
Member
Registered: 2019-11-19
Posts: 7

ECU Battery Supply

2.0L HDI 2004 Bosch ECU.
Do these ECUs have a permanent battery supply? ie. battery voltage with ignition off, key out.
With a battery voltage of 12.41 Volts and using a high resistance DVM  with the ECU not connected (off the vehicle) and the ignition key out.  I have the following:

Plug .1. Blue Plug. One of the connections reads 11.86 Volts

Plug .2. Middle Plug. One of the connections reads 12.02 Volts.

Plug .3. Blue Plug (Thick Wires) No voltage detected.

Is this as it should be and where do these less than battery voltages come from.

Tony.

Last edited by Tony Jones (2019-11-25 00:16:59)

Offline

#2 2019-11-25 02:50:22

kenbw2
Member
From: Bradford/Preston/Anywhere
Registered: 2017-11-26
Posts: 475

Re: ECU Battery Supply

Those voltages are probably just battery voltage with some resistance factored in (long wires, corroded connections)


2000 Citroen Dispatch 1.9TD XUD9 Camper Conversion + full time home
1999 Citroen Dispatch 1.9D DW8 Disassembled Camper Conversion
1996 Peugeot 806 1.9TD XUD9 Spare vehicle
1998 Citroen Synergie 1.9TD XUD9 Snapped timing belt

Offline

#3 2019-11-25 11:57:15

Tony Jones
Member
Registered: 2019-11-19
Posts: 7

Re: ECU Battery Supply

I don't see how they are due to resistance with no load applied, the DVM has such a high internal resistance that it would still show the battery voltage through a wet piece of string.
If it ever stops raining I will repeat the test with some load applied and see how the voltage falls.
The wires with this voltage appearing on them are very thin and I don't know how they are protected against over current and or short circuit.

Offline

Board footer