As far as I know: coming from Europe before 2001, it's probably an OBD1 truck. Therefore you read the codes with de paperclip-method via the diagnostics port, as stated in the link posted by Retrofive. (with OBD1 trucks you read all the codes with this method, on the OBD2 trucks used to reset the ABS/airbags/etc)No this diagnostic connector is for ABS and airbags according to the manual