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Engine guides and mods

MHD Starter/ECO Fault

There is a new common fault on the 451 MHD that causes the starter to stop working

Modification Details


Micro Hybrid Drive, a nonsense acronym that has nothing to do with a real hybrid engine.
It is just a moniker that means that the engine has stop/start technology.
When the car stops and your foot is on the brake pedal, the engine turns off.
When you release the brake pedal, the engine immediately restarts.

It was an option (that no one specced) from October 2007.
It was standard fitment from October 2008.

ECO Engine Light Flashing Or No Start

The idea of the MHD system is that when the car stops moving and you have your foot

on the brake, the engine stops to save fuel. As soon as you lift your foot from the
brake pedal the engine automatically starts up again so you can drive off.

The problem occurs one day when you pull up to a set of traffic lights or a traffic jam, the engine
turns off as normal but then refuses to automatically restart when you lift off the brake.
You can also get lesser symptoms such as the ECO light flashing.

In some cases the car won't even start when you use the key as you would normally.

The problem is usually due to the wiring loom. It is either too short and stresses the wires, unable to cope
with the vibration of the engine or suffers badly from the harsh environment in the engine bay.


Anyone with a slight knowledge of cars will know what the alternator looks like.
It's no different in the MHD despite having a starter motor built in.
Open the engine bay and look to the right rear of the aperture.

Circled below is the problematic connection.


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