Sunfire L4-144 2.4L DOHC VIN T SFI (2001)
Powertrain Control Module: Description and Operation
Powertrain Control Module (PCM)
The Powertrain Control Module (PCM), located under the instrument panel, is the control center of the fuel injection system. The PCM constantly looks
at the information from various sensors, and controls the systems that affect emission or engine performance. The PCM also performs the diagnostic
function of the system. The PCM can recognize operational problems, alert the driver through the Malfunction Indicator Lamp (MIL), and store a
Diagnostic Trouble Code (DTC) or DTCs which identify the problem areas to aid the technician in making repairs.
EEPROM
This assembly contains the functions of the Electrically Erasable Programmable Read-only Memory (EEPROM) and is a permanent part of the PCM.
The EEPROM contains the calibrations needed for a specific vehicle applications and is serviced only through a re-programming procedure.
Use of Circuit Testing Tools
Do not use a circuit test lamp in order to diagnose the powertrain electrical systems unless specifically instructed by the diagnostic procedures. Use the J
35616-A connector test adapter kit whenever the diagnostic procedures call for probing any of the connectors.
SYS Status & Drive Cycle For Satisfying the Federal I/M 240 Regulations
The System Status selection is included in the scan tool System Info menu.
Several states require that the I/M 240 (OBD II system) pass on-board tests for the major diagnostics prior to having a vehicle emission inspection. This
is also a requirement to renew license plates in some areas.
Using a scan tool, the technician can observe the System Status in order to verify that the vehicle meets the criteria which comply with local area
requirements. Using the System Status display, any of the following systems or a combination of the systems may be monitored for I/M Readiness:
^
The catalyst
^
The Oxygen Sensor (O2S)
^
The Heated Oxygen Sensor (HO2S)
^
The HO2S heater
IMPORTANT: The System Status display indicates only whether or not the test has been completed. The System Status display does not necessarily
mean that the test has passed. If a Failed Last Test indication is present for a Diagnostic Trouble Code (DTC) associated with one of the above systems,
that test is failed. Diagnosis and repair is necessary in order to meet the I/M 240 requirement. Verify that the vehicle passes all of the diagnostic tests
associated with the displayed System Status prior to returning the vehicle to the customer. Refer to the Typical OBD II Drive Cycle table (more than one
drive cycle may be needed) to use as a guide to complete the I/M 240 System Status tests.
Following a DTC info clear, the System Status will clear only for the systems affected by any DTCs stored. Following a battery disconnect or a control
module replacement, all of the System Status information will clear.
