The diagnostic socket is located under the cubby box. The socket is constructed to ISO standard and allows attachment of TestBook or any other ISO standard scantool. The diagnostic socket allows diagnostic information from the Anti-lock Braking System (ABS) ECU, the alarm ECU, or the Engine Control Module (ECM) to be retrieved.
Operation
Feed from the battery positive terminal is connected to fusible link 5 of the engine compartment fuse box (C0632-1) by a brown wire. Fusible link 5 (C0570-2) is connected to fuse 8 of the passenger compartment fuse box (C0580-15) by a brown/white wire. Fuse 8 of the passenger compartment fuse box (C0580-16) then provides a battery feed to the diagnostic socket (C0040-16) on a purple wire. Two earth paths are provided for the socket (C0040-4 & C0040-5), both on black wires.
To allow TestBook to retrieve diagnostic information from the various control units on Defender 1999 MY, the diagnostic socket is connected in the following way;