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en | 4 8 | User guide | HDS 200 HD Scan Tool for Class 4-8 Diesel, Light and Medium Vehicles
PCM indicating the temperature of the incoming air. The
PCM uses this signal for fuel delivery calculations.
Max:
Maximum
Mgt:
Management
MIL:
Malfunction indicator lamp. The MIL is most commonly
known as the check engine or service engine soon light.
A required on-board indicator to alert the driver of an
emission-related malfunction.
Min:
Minimum
Misfire:
Caused by the air fuel ratio being incorrect.
Monitor:
A test performed by the on-board computer to verify
proper operation of emission-related systems or compo-
nents.
MPFI or MFI:
Multi-port fuel injection. MPFI is a fuel injection system
using one (or more) injector(s) for each cylinder. The
injectors are mounted in the intake manifold, and fired in
groups rather than individually.
Neu:
Neutral
Nom:
Nominal
NOx:
Oxides of nitrogen. The system EGR and Camshafts
injects exhaust gases into the intake manifold to reduce
these gases at the tailpipe.
O2S:
Oxygen sensor. Generates a voltage of 0.6 to 1.1 volts
when the exhaust gas is rich (low oxygen content). The
voltage changes to 0.4 volts or less when the exhaust
gas is lean (high oxygen content). This sensor only oper-
ates after it reaches a temperature of approximately
349ºC (660ºF). O2 sensors are usually found both
upstream and downstream of the catalytic converter.
The PCM uses these sensors to fine tune the air-fuel
ratio and to monitor the efficiency of the catalytic con-
verter. See Bank 1, Bank 2, Sensor 1, Sensor 2.
OBD II:
On-board diagnostics, second generation. OBD II is a
U.S. Government-mandated standard requiring all cars
and light trucks to have a common data connector,
connector location, communication protocol, DTCs and
code definitions. OBD II first appeared on vehicles in
late 1994, and is required to be present on all cars sold
in the US after January 1, 1996.
ODM:
Output device monitor
OP:
Operating
Open loop (OL):
A control system mode that does not monitor the output
to verify if the desired results were achieved. A fuel
581618 | REV. A | 11.2017
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-
Bosch Automotive Service Solutions Inc.
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