User Manual

581618 | REV. B | 11.2018
Bosch Automotive Service Solutions Inc.
HDS 200/HDS 250
HD Scan Tool for Class 4-8 Diesel, Light and Medium Vehicles
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User guide | 49
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en
A control system mode that does not monitor the output
to verify if the desired results were achieved. A fuel
delivery system usually operates 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.
Out:
Output
PCM:
Powertrain control module. The brains of the engine and
transmission control systems 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).
Pct:
Percent
Pending codes:
Also referred to as continuous memory codes and matur-
ing diagnostic trouble codes. Pending codes may be set
by emission related powertrain components and sys-
tems. If the fault does not occur after a certain number
of drive cycles, the code is erased from memory.
Perf:
Performance
PID:
Parameter identification. Identifies an address in mem-
ory which contains vehicle operating information.
PNP:
Park/neutral position. 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 operates the engine in
an idle mode.
Pos:
Position
Pot:
Potential
Press:
Pressure
PROM:
Programmable read-only memory. The PROM contains
programming information the PCM needs to operate a
specific vehicle model/engine combination.
Prop:
Propulsion
Psngr:
Passenger
PSPS:
Power steering pressure switch
PTO:
Power takeoff
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 ener-
gizes the Purge Solenoid so the trapped vapors are
drawn into the engine and burned.
PWM:
Pulse width modulated
Pwr:
Power
PZM:
Platform zone module
QDM:
Quad driver module
RAM:
Random access memory
Recirc:
Recirculation
Ref:
Reference
Regen:
Regenerative
Rel:
Relative
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.
Req:
Requested
Req:
Request
ROM:
Read-only memory. Permanent programming information
stored inside the PCM, containing the information the
PCM needs to operate a specific vehicle model/engine
combination.
RPM:
Revolutions per minute
Rtrdr:
Retarder
SAE:
Society of Automotive Engineers
Scan tool:
A device that interfaces with and communicates informa-
tion on a data link.
SDM:
Sensing and diagnostic module
Sensor x:
A standard term used to identify the location of oxygen
sensors. Sensor 1 is located upstream of the catalytic
converter. See O2S, Bank 1, Bank 2.
Sensor:
Any device that reports information to the PCM. The job
of the sensor is to convert a parameter such as engine
temperature into an electrical signal that the PCM can
understand.