Acura 3.5 RL Manual page 357

PCM Data
You can retrieve data from the PCM by connecting the OBD II scan tool or the Honda PGM Tester to the Data Link
Connector (DLC). The items listed in the table below conform to SAE recommended practice. The Honda PGM Tester also
reads data beyond that recommended by SAE so that this data may help you find the causes of intermittent problems.
NOTE:
• The "operating values" listed are approximate and may vary depending on the environment and the individual vehicle.
• Unless noted otherwise, "at idle speed" means idling with the engine completely warmed up, transmission in Park or
neutral, and the A/C and all accessories turned off.
Data
If the PCM detects a problem, it will store it as a code
Diagnostic
consisting of one letter and four numbers.
Trouble Code
(DTC) Depending on the problem, an SAE-defined code
(P0xxx) or a Honda-defined code (P1xxx) will be output
to the tester.
Engine Speed The PCM computes engine speed from the signals sent
from the Crankshaft Position (CKP) sensor.
This data is used for determining the time and amount
of fuel injection.
Vehicle Speed The PCM converts pulse signals from the Vehicle
Speed Sensor (VSS) into speed data.
Manifold The absolute pressure created in the intake manifold by
Absolute engine load and speed.
Pressure (MAP)
Engine Coolant The ECT sensor converts coolant temperature into
Temperature voltage and signals the PCM. The sensor is a thermistor
(ECT) whose internal resistance changes with coolant
temperature. The PCM uses the voltage signals from
the ECT sensor to determine the amount of injected
fuel.
Heated Oxygen The HO2S detects the oxygen content in the exhaust
Sensor (HO2S) gas and sends voltage signals to the PCM. Based on
(Bank 1, Sensor 1) these signals, the PCM controls the air/fuel ratio. When
(Bank 2, Sensor 1) the oxygen content is high (that is, when the ratio is
(Sensor 2) leaner than the stoichiometric ratio), the voltage signal
is lower. When the oxygen content is low (that is, when
the ratio is richer than the stoichiometric ratio), the
voltage signal is higher.
Description Operating Value
If no problem is detected,
there is no output.
Nearly the same as
tachometer indication at
idle speed:
650 ± 50 rpm
Nearly the same as
speedometer indication
With engine stopped:
Nearly the same as atmo-
spheric pressure.
At idle speed:
24 - 37 kPa (180 - 280
mmHg, 7.1 - 11.0 inHg)
With cold engine:
Same as ambient temper-
ature and IAT
With engine warmed up:
approx. 158 - 212°F
(70 - 100°C)
0.0 - 1.25 V
At idle speed:
about 0.1 - 0.9 V
Freeze Data
YES
YES
YES
YES
YES
NO