Thread: Engine Shutdown

Inertia switch faulty.

I had this issue when i first got my defender. Apparently the inertia switch can rattle a screw loose and it needs to be re fastened / replaced to secure it (and stop the problem).

Inertia switch on my D2 tripped when I hit a raised train crossing at 100km/h...
Echo the others, check the inertia switch

Sent from my HTC One using AULRO mobile app

Thanks, thats great, but where is the inertia switch located (I am still waiting for my repair manual to turn up)?

I am not sure on a Puma but likely to be in engine bay so look near air box, battery etc, even firewall and look for a little black thing with a rubber top and slight depression on top where you can put your fingertip and press to reset. The whole thing might be the size of a squashed pack of matches - ie fatter but not as tall.

Cheers

It's on the firewall, in the middle.
From the FSM p.947 (in my version):

"The inertia switch, when activated, causes the ECM to disable engine fuel injection and the fuel tank pump.
The inertia switch is installed in the engine compartment, on the engine bulkhead. When the ignition switch is in the
ignition on and crank positions, battery voltage from the BJB is supplied to the inertia switch. While the inertia switch is in
the de-activated state, the voltage passes through the normally closed contacts of the switch to the ECM. If an impact of a
given force occurs, the inertia switch contacts open and disconnect the voltage signal to the ECM.
After it has been activated, the inertia switch can be reset by pressing down on the rubber cap."

It's a normally closed switch, so an intermittant fault in the wiring which causes an open circuit will trigger it... so keep that in mind also. Crude test is to poke and wiggle the wiring to try and induce the symptoms.

It looks like this (not my pic):