Circuit Description
The Module Diagnostic Check is an organized approach to identify problems
associated with the module. This check must be the starting point for any
module complaint, and will direct you to the next logical step in diagnosing
the complaint. The module is a very reliable component and is not likely
the cause of the malfunction. Most system complaints are linked to faulty
wiring and connectors, and occasionally to components. Understanding the
computer system and using the tables correctly will reduce diagnostic time
and prevent unnecessary parts replacement.
Diagnostic Aids
| • | The following conditions may result in an intermittent operation
of the module with no DTC stored: |
| - | Any condition which results in the interruption of power to the
module |
| - | Out of range battery or ignition voltage |
Specification
Normal module operating voltage: 9.0-16.0 V
| - | A loose or damaged ground(s) |
| - | An open or shorted serial data line |
| • | An intermittent failure in the electronic system may be very difficult
to detect and to accurately diagnose. The module tests for different malfunctions
under different vehicle conditions. For this reason, a thorough test drive
is often needed in order to repeat a malfunction. If the system malfunction
is not repeated during the test drive, a good description of the complaint
may be very useful in locating an intermittent malfunction. Faulty electrical
connections or wiring causes most intermitting problems. When an intermittent
condition is suspected, check the suspected circuits for the following conditions: |
| - | Poor mating of connector halves or backed out terminals |
| - | Improperly formed or damaged terminals |
| - | Poor wire-to-terminal connections |
| - | Dirty or corroded terminals |
| - | Damage to connector bodies |
| • | Use the J 35616
whenever a diagnostic procedure requests probing or checking a terminal.
Using this adapter will ensure that no damage to the terminal will occur,
and will give an idea of whether contact tension is sufficient. |
| • | If the DTC is a history DTC, the problem may be intermittent.
Perform the tests shown while moving related wiring and connectors. This can
often cause the malfunction to occur. Perform a thorough inspection of all
related wiring and connectors pertaining to the history DTC stored. |
| • | Exit all Scan Tool
tests before cycling the ignition from RUN to OFF unless the scan
tool instructions direct otherwise. Follow the operating instructions
in the Scan Tool
operator's
manual. Failure to follow these instruction may set DTCs, cause vehicle
system malfunctions, set false DTCs, or cause Scan Tool
malfunctions. |
