F 150 4WD Pickup V8-4.6L SOHC VIN W (1998)
Multifunction Electronic Control Module: Description and Operation
Central Timer Modules (CTMs) are equipped on two-wheel drive vehicles without power windows. All other vehicles have a Generic Electronic Module
(GEM).
NOTE: CTM diagnostics are not compatible with the New Generation STAR (NGS) Tester; instead, the diagnostics are internal to the module. The
diagnostic mode is entered by shorting two pins of the diagnostic connector together.
The GEM inputs and outputs are designed to withstand continuous exposure to a short circuit to ground or battery voltage without being damaged.
GEM Diagnostics
The GEM diagnostics are accessible with the New Generation Star Tester and the Service Bay Diagnostic System (SBDS). The GEM constantly
monitors its subsystems for concerns. If a concern is found in one of the subsystems, the GEM will record the concern in the form of a Diagnostic
Trouble Code (DTC).
There are three areas of diagnostic information useful when diagnosing the GEM.
^
DTCs A record of past or present system problems.
