Ecm Data - Honda S2000 Service Manual

EGM Data
You can retrieve data from the ECM by connecting the OBD ll 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 PGlvl Tester
also reads data beyond that recommended by SAE to 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, in neutral position, and
the Ay'C and all accessories turned off.
Data Description
ODeratino Value Fleeze Data
Diagnostic
Trouble Code
(DTC)
lf the ECM detects a problem. it will store it as a code
consisting of one letter and four numbers. Depending on
the Droblem, an SAE-defined code (Poxxx) or a Honda-
defined code (P1xxx) will be output to the tester.
lf no problem is
detected. there is no
outpul.
Y E S
E n g i n e S p e e d
The ECM computes engine speed from the signals sent
from the Crankshaft Position (CKP) sensor. This data is
used for determining the time and amount of injected fuel.
N e a r l y t h e s a m e a s
tachometer indication
At idle speed: 800+50
r D m
YES
Vehicle Speed
The ECM converts pulse signals from the Vehicle Speed
Sensor (VSS) into speed data.
Nearly the same as
speeoomeler
indication
YES
Ma n ifold
Absolute
Pressure
( M A P )
The absolute pressure caused in the intake manifold by
e n g i n e l o a d a n d s p e e d .
With engine stopped:
Nearly the same as
atmosphenc pressure
At idle speed: 28 48
kPa (2'10 360 mmHg,
8 . 3 1 4 . 2 i n H o )
YES
E n g i n e
Coolant
Temperature
(ECr)
The ECT sensor converts coolant temperature into voltage,
and sends a voltage signal to the ECM. The sensor is a
thermistor whose internal resistance changes with
coolant temperature. The ECM uses the vollage signals
from the ECT sensor to determine the amount of injected
f u e l .
With cold engine:
S a m e a s a m b i e n t
temperature and IAT
With engine warmed
up: approx. 176 212"F
(80 100'c)
YES
Primary
Heated
Oxygen
S e n s o r
( P r i m a r y
H O 2 5 ) { S e n s o r
1 ) , S e c o n d a r y
Heated
Oxygen
Sensor
{Secondary
H O 2 S ) ( S e n s o r
2 l
The HO2S detects the oxygen content in the exhaust gas
and sends voltage signals to the ECM. Based on these
signals, the ECM controls the airlfuel ratio. When the
oxygen content is high (that is, when the ratio is 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
h l o h e r .
0 . 0 - 1 . 2 5 V
At idle speed:
a b o u t 0 . 1 0 . 9 V
NO
{cont'd)
11-11