Actron Professional Enhanced Scan Tool 9640A, User Manual

Page: 122 / 126

Glossary
B – 6 • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
B
ODM:
Output Device Monitor.
Open Loop (OL):
A control system mode that does not monitor the output to verify if the desired results
were achieved. A fuel delivery system will usually operate in open loop mode during cold
engine warm-up because the oxygen sensors are not yet ready to send a signal. Without
the oxygen sensor signal, the computer cannot check the actual results of combustion.
PCM:
Powertrain Control Module. The “brains” of the engine control system housed in a metal
box with a number of sensors and actuators connected via a wiring harness. Its job is to
control fuel delivery, idle speed, spark advance timing, and emission systems. The PCM
receives information from sensors, then energizes various actuators to control the
engine. The PCM is also known as the ECM (Engine Control Module).
Pending Codes:
Also referred to as Continuous Memory codes and Maturing Diagnostic Trouble codes.
These codes are set when intermittent faults occur while driving. If the fault does not
occur after a certain number of drive cycles, the code is erased from memory.
PID:
Parameter Identification. Identifies an address in memory which contains vehicle oper-
ating information.
PNP:
Park/Neutral Position. This is a switch that tells the PCM when the gear shift lever is in
the Park or Neutral position. When in Park or Neutral, the PCM will operate the engine
in an “idle” mode.
PROM:
Programmable Read-Only Memory. The PROM contains programming information the
PCM needs to operate a specific vehicle model/engine combination.
PSPS:
Power Steering Pressure Switch
Purge Solenoid:
Controls the flow of fuel vapors from the carbon canister to the intake manifold. The
canister collects vapors evaporating from the fuel tank, preventing them from escaping
to the atmosphere and causing pollution. During warm engine cruise conditions, the PCM
energizes the Purge Solenoid so the trapped vapors are drawn into the engine and
burned.
PWM:
Pulse Width Modulated
PZM:
Platform Zone Module
QDM:
Quad Driver Module
RAM:
Random Access Memory
Relay:
An electromechanical device in which connections in one circuit are switched
Reluctance Sensor:
A type of sensor typically used to measure crankshaft or camshaft Speed and/or position,
driveshaft speed, and wheel speed