General Rules For Use of All Jds Software

(including 4040)

-Only use JDS when an electrical fault is present - do not attempt to diagnosis intermittent faults.

The engine management system and electronic transmission are exceptions to this rule, when using DBC 4040. However, when an intermittent fault is stored in an ECU with serial communication JDS will only provide guidance as to the fault's area, it will not pin-point diagnosis an intermittent fault.

-Do not assume that every system fault is electrical - check the operation of vacuum and mechanical systems first.

-When a JDS prints a fault description on the trace, part condemnation should not be automatic - the trace should be read (refer to Technical Bulletin JDS no. 46).

EXAMPLE: If JDS prints "bulkhead harness" as a description, the trace should be read and the wire/connector pins in the faulty circuit should be checked.