S10/T10 Blazer 2WD V6-262 4.3L VIN Z (1994)
When the PCM is commanding a device or a component "ON," the voltage potential of the output is "LOW" or near zero volts. When the PCM is
commanding a device or component "OFF," the voltage potential of the circuit will be "HIGH," or near 12 volts. The primary function of the QDM is
to supply the ground for the component being controlled.
The input information has an interrelation between sensor output. If one of the input devices failed, such as the oxygen sensor, this could affect more
than one of the systems controlled by the computer.
The PCM has two parts for service:
-
Controller which is the PCM (93 PCM6), without the PROM (MEM-CAL).
-
PROM (Programmable Read Only Memory) which is a separate memory calibrator unit
PCM Learning Ability
The PCM has a "learning" ability which allows it to make corrections for minor variations in the fuel system to improve driveability. If the battery
is disconnected, to clear diagnostic trouble codes or for other repairs. the "learning" process resets and begins again. A change may be noted in the
vehicle's performance. To "teach" the vehicle, ensure the engine is at operating temperature. The vehicle should be driven at part throttle, with
moderate acceleration and idle conditions until normal performance returns.
NOTE The PCM must be maintained at a temperature below 85°C (185°F) at all times. This is most essential if the vehicle is put through a baking
process. The PCM will become inoperative if it's temperature exceeds 85°C (185°F). It is recommended that temporary insulation be placed around
the PCM during the time the vehicle is in a paint oven or other high temperature processes.
