Powertrain Control Module (Pcm) Diagnosis; Multiple Pcm Information Sensor - Isuzu 1999 RODEO Workshop Manual

POWERTRAIN CONTROL MODULE
(PCM) DIAGNOSIS
To read and clear diagnostic trouble codes, use a Tech 2.
IMPORTANT: Use of a Tech 2 is recommended to clear
diagnostic trouble codes from the PCM memory.
Diagnostic trouble codes can also be cleared by turning
the ignition OFF and disconnecting the battery power
from the PCM for 30 seconds. Turning off the ignition and
disconnecting the battery power from the PCM will cause
all diagnostic information in the PCM memory to be
cleared. Therefore, all the diagnostic tests will have to be
re–run.
Since the PCM can have a failure which may affect only
one circuit, following the diagnostic procedures in this
section will determine which circuit has a problem and
where it is.
If a diagnostic chart indicates that the PCM connections
or the PCM is the cause of a problem, and the PCM is
replaced, but this does not correct the problem, one of the
following may be the reason:
RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
014RX002
901RX031
f There is a problem with the PCM terminal
connections. The terminals may have to be removed
from the connector in order to check them properly.
f EEPROM program is not correct for the application.
Incorrect components or reprogramming the PCM
with the wrong EEPROM program may cause a
malfunction and may or may not set a DTC.
f The problem is intermittent. This means that the
problem is not present at the time the system is being
checked. In this case, make a careful physical
inspection of all components and wiring associated
with the affected system and refer to the Symptoms
portion of the manual.
f There is a shorted solenoid, relay coil, or harness.
Solenoids and relays are turned ON and OFF by the
PCM using internal electronic switches called drivers.
A shorted solenoid, relay coil, or harness will not
damage the PCM but will cause the solenoid or relay
to be inoperative.
MULTIPLE PCM INFORMATION
SENSOR DTCs SET
Circuit Description
The powertrain control module (PCM) monitors various
sensors to determine the engine operating conditions.
The PCM controls fuel delivery, spark advance, and
emission control device operation based on the sensor
inputs.
The PCM provides a sensor ground to all of the sensors.
The PCM applies 5 volts through a pull–up resistor, and
determines the status of the following sensors by
monitoring the voltage present between the 5–volt supply
and the resistor:
f The Fuel Tank Vapor Pressure Sensor
f The throttle position (TP) sensor
f The manifold absolute pressure (MAP) sensor
The PCM provides the following sensors with a 5–volt
reference and a sensor ground signal:
f The Linear exhaust gas recirculation (EGR) valve
f The A/C Pressure Sensor
The PCM monitors the separate feedback signals from
these sensors in order to determine their operating
status.
Diagnostic Aids
Be sure to inspect PCM and engine grounds for being se-
cure and clean.
A short to voltage in one of the sensor input circuits may
cause one or more of the following DTCs to be set:
f P0108/P1106
f P0113/P1111
f P0118/P1115
f P0123/P1121
f P0463
If a sensor input circuit has been shorted to voltage, en-
sure that the sensor is not damaged. A damaged sensor
6E1–65