Vehicle ground connection diagnostic

A vehicle ground connection diagnostic method comprising:

• sensing a voltage on each of a plurality of ground connector lines, each ground connector line for providing a conduction path from an electronic control unit to ground;
• controlling switching on a plurality of switches in a connected state, the plurality of switches each being associated with a respective ground connector line and being switchable from a connected state where the conduction path for the respective ground connector line connects the electronic control unit to ground to a disconnected state where the conduction path is disconnected from ground;
• and
• identifying a ground connection fault in each individual ground connection line based on identifying a change in sensed voltage characteristics on one of the ground connection lines between condition (a) when the or all other switches are switch to a connected state and condition (b) when the switch for the one ground connection line is switched to the connected state and the or all switches for the or all other ground connection lines are switched to a disconnected state;
• wherein identifying the change in the sensed voltage characteristics further comprises comparing a sensed voltage on one of the plurality of ground connection lines under condition (a) with a sensed voltage on the one ground connection line under condition (b);
• and
• wherein the controller is configured to identify the ground connection fault on the one of the plurality of ground connection lines when the sensed voltage is higher under condition (b) than under condition (a).

A vehicle comprising:

• an electronic control unit;
• and
• a vehicle ground connection diagnostic apparatus comprising:
• one or more voltage sensors for sensing the voltage on each of a plurality of ground connector lines, each ground connector line for providing a conduction path from the electronic control unit to ground;
• a plurality of switches in a connected state, the plurality of switches each being associated with a respective ground connector line and being controllable for switching from a connected state where the conduction path for the respective ground connector line connects the electronic control unit to ground to a disconnected state where the conduction path is disconnected from ground;
• and
• a controller configured to control the plurality of switches and for identifying a ground connection fault in each individual ground connection line based on identifying a change in sensed voltage characteristics on one of the ground connection lines between condition (a) when the switches are in a connected state and condition (b) when the switch for the one ground connection line is in the connected state and the or all switches for the or all other ground connection lines are in a disconnected state;
• wherein:
• the change in sensed voltage characteristics is determined based on comparing a sensed voltage on one of the plurality of ground connection lines under condition (a) with a sensed voltage on the one ground connection line under condition (b);
• the controller is configured to identify the ground connection fault on the one of the plurality of ground connection lines when the sensed voltage is higher under condition (b) than under condition (a);
• and
• the electronic control unit is configured to process a fault diagnostic signal generated by the vehicle ground connection diagnostic apparatus.