Freelander 2 (LR2) FL2 SD4 Turbo actuator vane fail

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Hippo

Lord Hippo
Posts
51,748
MY15 SD4 uk spec.
Drove home ok with no problem. Stop and start the engine twice to open gates and garage doors. On the second start 'restricted performance' appeared on the dash. Checked the diagnostic and no error codes. Looked at the dpf and it was on 22. Doesn't need regeneration to empty it until 24, but even at that figure it will continue to drive. Took it for a drive to perform a dpf regeneration and it didn't. FL was low on power all the way because the turbo's not running. Limited to 2k5 revs. Fault codes appeared half way through the trip as below. This is the first time this fault has appeared. Fault seems permanent.

P0046-19 (AF) turbo boost control solenoid - circuit range/performance - general electrical failure - circuit current above threshold.
P0047-11 (AC) turbo boost control solenoid - circuit low - general electrical failure - circuit short to ground.
P259E-73 (EC) turbo A boost control position at low limit - mechanical failure - actuator is stuck closed.

Lots of different views and similar codes from others who have had the same problem. Normally actuator or turbo needs replaced.

Took it home to investigate. Tried cleaning the actuator 5 way connection. Fault still present. Took the connector off and measured the wiring harness resistance to battery negative 0v terminal results as below:

Yellow 1749ohm
Gray 0.2ohm
Yellow blue 10k51ohm
Blue 4meg ohm
White 4meg ohm

Looking at the circuit in the big FL2 maintenance manual on page 3119 shows all 5 wires going directly to the ECM Engine Control Module. Can anyone confirm from their own measurements if the gray wire should be connected directly to 0v or not?
I don't know if this wire is a 0v signal return path or if the actuator uses it's metal case connection for the 0v return. If so then this is my fault.

Further investigation: actuator arm will move if you push it. Springs back by itself. Followed the wiring harness taking all connectors oft other items one at a time, to the top rear of the engine. Only one I can't see to disconnect. Made no difference to the measurement on the gray wire. Took the 3 connectors oft the Engine Control Module which sits to the rear of the engine, under the wipers, and the gray wire short to 0v disappears. Through process of elimination I worked out the left and right connectors need to be fitted for the short to appear. Still looking at this but can't find any resistance values other owners have put online for the actuator vane 5 wire connection.

Edit: answer yes, it's a wired 0v singal in the harness.
 
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I have disconnected the actuator arm and it moves freely (still connected to the turbo). So that should mean the turbo vanes are moving ok and not stuck. There is some resistance on the actuator motor but I’m turning the output end which makes sense. Looking at the wiring diagram again the signal I’m questioning has G_R_ in its name. There’s some 2 wire sensors that have the same on one of their wires so I’m assuming this means ground return. Hence measuring a short to ground must be correct. I questioned this as the fault codes report a short to ground. But that may not be the full story. From what I see there’s a catch 22 setup where the car sends a control. It has two ways of knowing if this has worked. Feedback via turbo movement or the electrical feedback signal on the actuator. The actuator has a pcb inside but I haven’t opened it up to see it. Not sure if it only takes instruction from the car or if it’s capable of a two way conversation. The manual says the car receives feedback via a signal. I think this is the yellow/blue wire. So that leaves me stuck as I don’t know if the car has chosen to stop trying to control the actuator or not. Lots of others on ere and online have had trouble with the actuator only or the whole turbo. I have found a company online who can test and repair the actuator arm if needed. I will let you know the result of this. I suspect the actuator is the cause of the problem form what I have found so far. Knowing if it’s ok gives me a datum to work oft to investigate further if needed.
 
Said actuator is faulty. Company I sent it to have confirmed this. I have just paid to have it repaired and posted back to me.
 
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