For intelligent and efficient troubleshooting, it is necessary to use special measuring instruments, which are very expensive and usually only available in workshops. In this regard, only basic checks are described here: checking the voltage and state of charge of the battery and checking the fuses (see ch. «electrical equipment»).
Disconnect and connect all plugs of the relevant electronic systems. Check the tightness of the plugs and the fastening of the wires in the engine compartment.
Check all ground connections for tightness and quality.
Check hoses and wires for leaks, and check connections for tightness, corrosion or other damage.