Member Since: 01 Jan 2014
Location: Dumfries, Scotland
Posts: 84
Engine ECU
Still chasing cruise control problem, only thing left is engine ecu and lack of full 5 volts out ecu for cruise control, only getting 4.3 volts.
Can a second hand ecu be fitted and programmed to my car. Does it have to be a virgin one, all data wiped ready for programming ? What is capable of doing this ?
If a borrowed a secondhand ecu and plugged into car, I know it wouldn't start but will it be recognised and would I be able to see what's happening ie cruise control voltage provided it can from a car with cruise activated.
Other option is to send ECU away for testing but any company I have spoken to either cant do this ECU or unable to confirm if this part of ECU is tested 😠.
Or could one of you guys test your cruise control voltage at the switch with switch disconnected voltage going to pin 9 on the connector that plugs into the switch.
Thanks
22nd Feb 2015 5:39 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
If you are suspecting a voltage drop on the 5v ref then looking at the state of the ECU connector and checking it for signs of corrosion would be a good start. After that check the ECU is capable of outputting 5v when all the 5v circuits are disconnected. With the loom in your hand you could also do a resistance check but clearly this will be an unloaded circuit so only a gross-error check.
That said, 4.3v does not look really low due to the normal vd. I don't have a prescribed voltage or a recent test of the D3 cc ref circuit but here is one of the D4 MAF 5v references, read at a MAF on a loaded circuit:
Click image to enlarge
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 01 Jan 2014
Location: Dumfries, Scotland
Posts: 84
Checked everything many times and no further forward. Had spare time today and measured voltage out ecu and was getting 4.3 at ecu, connect the switches and it drops to 3.9 .
Bit confused now or been over straining the grey mater but why am I getting 3.9 out ecu with switches connected, now thinking I should see 4.3 before switches and 3.9 returning down other wire due to inline resistance. Thought 4.3 would be constant. Getting full 5 volts at maf. Also SSD says both internal 5 volt circuits are at 5volts.
Would love to poke the 5volts from maf down cruise wire to see but as car is fine in all other departments it not worth the risk.
Wonder if wires are crossed and firing the 4.3 round the circuit the wrong way at the connector between wheel and switch, ended up making a good one out of the new one I ordered and the old as new was broken before even getting fitted.
22nd Feb 2015 7:04 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
With no load connected I would expect 5v at the ECU. I don't have SDD access anymore so I don't know how many in dependant regulated 5v sources the ECU has. Often they appear independent but are ganged inside the ECU. Does SDD clarify this at all?Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 01 Jan 2014
Location: Dumfries, Scotland
Posts: 84
Yes SSD does list the internal voltage of the 5 volt out put and I am sure it lists 2 and both show 5 volts can't remember exact wording. Am I right saying 5 volts should be constant ?
What are the other 5 volt systems fed from the ECU ? I could disconnect the MAF wiring and other 5 volt systems and see if cruise reference goes up.
Off tomorrow so can play with it. If like you say they are linked together I could borrow the 5 volts from somewhere and feed into cruise and see if it works. ECU will only be interested in voltage returning to ECU not where its come from.
22nd Feb 2015 9:08 pm
Disco_Mikey
Member Since: 29 May 2007
Location: Dundee, Scotland
Posts: 20834
Correct
I'll take my airbag out tomorrow and check the voltage, as a reference My D3 Build Thread
Member Since: 01 Jan 2014
Location: Dumfries, Scotland
Posts: 84
That would be great Mikey
Need to recheck some measurements tomorrow because I don't understand why the out put voltage drops when switches connected, does it with 2 different switch sets.
Calls for a bit of logical fault finding with results noted and not kept in my head
22nd Feb 2015 9:41 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
The voltage on the cc circuit should drop when the switches are connected as it is a resistive ladder with the neutral position applying a set amount of resistance which is further varied by switch selections.
It will be interesting to see Mike's baseline voltages in comparison.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 01 Jan 2014
Location: Dumfries, Scotland
Posts: 84
Robbie,
Agree with what you are saying but not 100% sure I am on the same wave length though, or its the way I reading it.
Getting 4.3 out ECU measured at ECU with feed to cruise disconnected, reconnect and measure voltage at switch connector 4.3. Connect switches and voltage on feed drops to 3.9, I would have thought that the ECU would try to maintain this voltage and voltage drop would be on the return back to the ECU. Why feed and return showing same voltage.
Just heading into garage, going to remove both feed and return for cruise from ECU, disconnect MAF, borrow its 5 volts, connect to cruise switch and run another wire to ECU for return voltage, just temporary and cruise connected under bonnet. Borrow my pals SSD and this will tell me if it thinks a button is pressed.
23rd Feb 2015 7:49 am
scaniaman
Member Since: 01 Jan 2014
Location: Dumfries, Scotland
Posts: 84
Got round to looking at this again. Took 5volt feed from maf and fed into cruise switches and returned down original wire to ecu. Still the same problem it still thinks a button is pressed but with the 5 volts it said something like cruise control increase distance button pressed. It now thinks I have adaptive cruise fitted . Borrowed another set of switches and tried with and with out 5 volts got same results. Cut both wires at ecu and rigged up under bonnet still getting same. Ecu u/s?
Can you fit a secondhand one and reprogram it to the car. If so what will do it. I now some makes have be wiped while still connected to original car.
Can you fit a secondhand one and reprogram it to the car. If so what will do it. I now some makes have be wiped while still connected to original car.
No you can't use second hand ecu for the EMS, it has to be a new one ordered fro your Vin and then reprogrammed with your software.
Flack
3rd Mar 2015 6:42 pm
Nodge68
Member Since: 05 Sep 2014
Location: Newquay
Posts: 1014
Forgive me if you have done this already but have you changed the wheel harness/ clock spring?
My CC wouldn't work when it should have. It turned out to be the wheel harness.Freelander SE 2005 Auto.
D3 TDV6. Gone.
3rd Mar 2015 7:15 pm
scaniaman
Member Since: 01 Jan 2014
Location: Dumfries, Scotland
Posts: 84
Loom and clock spring has been swapped for known working ones. That's why I cut the wires at ecu, as the wires were the only thing not replaced or swapped, and plumbed up with just 2 short wires and switches and still doing the same . Can send ecu away for testing but they are unable to tell me if they test this part or not.
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. Borrowed another set of switches and tried with and with out 5 volts got same results. Cut both wires at ecu and rigged up under bonnet still getting same. Ecu u/s?
. Can send ecu away for testing but they are unable to tell me if they test this part or not.
