Checking Modules

Unnecessary replacement of a module is the result of improper or inadequate testing.

• Understand correct module function. Read Description and Operation for the system.
• Make sure programmable parameters are set correctly for the function in question (Refer to Module Configuration ).
• Resolve DTC first -- as directed by service information diagnostics.
• Test all inputs, both hard-wired and networked.
• Test outputs (see "Checking module switching circuits" below).
• Check for module software updates (flash programming).

Checking Module Switching Circuits 

• Using the diagnostic scan tool module Output State Control function to activate components is a fast way to confirm an output is capable of being switched on and off by the module. Testing that reveals normal module output function confirms the need to analyze the module inputs.
• Do not apply ground or power directly to module switched components with jumper wires unless directed by a service information procedure, as the component could be damaged by a direct connection to ground or power.