Immobiliser issue solved

[shaby]

Hi all

Just thought I'd share something weird that I found out about my D40 (2013) - yeah I know...I'll keep it to 1 thing.

I've been having an issue with the immobiliser or more accurately the ignition not recognising the key when I insert it, which leads to the immobiliser not being disarmed. When I go to start all the lights on the dash don't come on, but the immobiliser light flashes and the starter motor doesn't kick over. I try this heaps - doesn't work. I use the good old insert the key into the ignition 7 times in quick succession and after 5 or 10 attempts at this the engine will kick over but by then the immobiliser has done its job and the fuel has drained back into the tank, so I have to then prime the engine. This issue has been happening for about a year and is quite random...I thought!

...but then, I found the issue. My mobile phone charger. That's correct - mobile phone charger; your literacy skills are still intact.

It seems that when the charger is plugged into the cigarette lighter port it draws power ALL the time - not that that really matters as it draws so little power...even though it is a fast charging cradle. What seems to be happening is that it somehow confuses the immobiliser. I think the following is happening:

The cradle sits within 10 centimeters of the ignition slot. (For those of you from the States, go look that up ... you are meant to be converting to metric, so just convert.) It is the sort of charger that will charge when a phone is in close proximity - doesn't plug into the phone. It works in the same way that some modern kettles do or how modern tooth brushes charge. So the charger is sending out a signal to start wireless magnetic charging. Similarly the immobiliser is sending out radio waves (RF). My good friend CoPilot has concurred with my suspicions, assuring me that "In summary, magnetic induction can indeed interfere with RF signals". Solution:
Make sure the cradle is unplugged before trying to start the engine.
Move the cradle to the centre of the car to reduce the interference.

Anyway, thought you might like to know as many of us have these phone cradles now and this is not an expected consequence. Since unplugging it has not reoccurred.

I'm happy to hear any alternate explanations, but this one works for me. Also I'd love it if others were willing to try it on if you have a powerful cradle charger and place it near the ignition slot for a few days - I have mine attached to the vent close to the drivers door. It'd be an interesting experiment.

Enjoy your day

shaby

 

[tweak'e]

by then the immobiliser has done its job and the fuel has drained back into the tank, so I have to then prime the engine.

fuel should never drain back to the tank. that usually indicates an air leak somewhere, air gets sucked into the line. common place is fuel filter.
some people add a one way valve back at the tank at a low point, which helps.

 

[shaby]

fuel should never drain back to the tank. that usually indicates an air leak somewhere, air gets sucked into the line. common place is fuel filter.
some people add a one way valve back at the tank at a low point, which helps.

Hi tweak'e - Thanks for your input. It is interesting as that is not what the 3 mechanics I went to about this said. They all indicated that as part of an immobiliser there is a valve that lets fuel return to the tank to make starting more difficult. Interesting that opinions vary on what should be a well known action. I never have any issue with fuel returning to the tank and me having to prime the fuel filter unless I have the phone cradle on when I go to try and start the vehicle. If I use your diagnosis that there is an air leak somewhere, then this would be apparent regardless of the phone cradle being on and emitting the magnetic field wouldn't you think?

Anyway, that is not the real point of the message. Regardless of whether drainage happens or not is superfluous to the overall ramification of having this technology so close to the ignition that relies on another technology that can be interfered with - that is what I was trying to outline.

 

[tweak'e]

Anyway, that is not the real point of the message. Regardless of whether drainage happens or not is superfluous to the overall ramification of having this technology so close to the ignition that relies on another technology that can be interfered with - that is what I was trying to outline.

agreed. thats absolutely correct. electrical noise can screw with the fob signal.
its a separate issue to the fuel and not related.

It is interesting as that is not what the 3 mechanics I went to about this said. They all indicated that as part of an immobiliser there is a valve that lets fuel return to the tank to make starting more difficult.

no. there is no special valve in the system for that. they are talking complete BS.
fuel draining back due to air leaks on the fuel line is a very common problem and it seams they made up an excuse to account for that, so they can make more $$ fixing other things.
i've had a lot of people who got quoted for an injection pump rebuild ($$$$) when it was simply an air leak issue, typically fuel filter or fuel primer (which has a one way valve in it). of course they swap out the filter when they rebuild the pump.

 

[tweak'e]

i'll add a bit.
there is a valve on the filter but thats a thermostatic valve to return hot fuel to the filter in cold weather. it also doesn't have electrical connections for an ecu to make it do anything. ie NATS can't control it.
there is no electrically operated valves in the fuel system. there is only the fuel pump and its control valve, the injectors and the over pressure return valve.
there is nothing open to the air for air to be sucked into the fuel lines.

so any air in the system is there because of a fault. as its a suction system any poor seal, hose connection, split hose end, worn o ring on the primer plunger, faulty return thermo valve etc, will allow air to be sucked in.

easy way to test is to fit a one way valve back at the tank.

 

[tweak'e]

o i forgot, later d40's have fuel lift pump in the tank.
in which case i'm surprised you have to prime it. most of them with lift pumps will self bleed.
come to thing of it i don't think they even have primers on those ones.

 

[Rhino1174]

I got to say it’s certainly makes sense that any rf interfering signals in that area may well disrupt the immobilization process that’s for sure I do wonder if it’s just a coincidence that air is in the system it should be fully closed loop and no way of outside air unless there is a leak I have worked as a diesel mechanic for 35 years and I have never heard or seen any such nonsense as the mechanics are telling you I would like to be proven wrong however I’m always willing to learn more I will give the cradle a go in my nav see what happens for you and get back to you cheers