The PCM controlled lamps are intended to alert the driver
to an operating condition which may require immediate attention. Refer to
Instrument Panel Description
,
Instrument Cluster Circuit Description
,
Head Up Display Operation
, and
Driver Information Center (DIC) or Message Center Circuit Description
in Instrument Panel, Guages, and Console for further information regarding
the IP Indicators..
MIL/Service Engine Soon Indicator
The Malfunction Indicator Lamp (MIL) is located on the instrument panel
and is displayed as CHECK ENGINE lamp.
MIL Function
| • | The MIL informs the driver that a malfunction has occurred and
the vehicle should be taken in for service as soon as possible |
| • | The MIL illuminates during a bulb test and a system test |
| • | A DTC will be stored if a MIL is requested by the diagnostic |
MIL Illumination
| • | The MIL will illuminate with ignition switch ON and the engine
not running |
| • | The MIL will turn OFF when the engine is started |
| • | The MIL will remain ON if the self-diagnostic system has detected
a malfunction |
| • | The MIL may turn OFF if the malfunction is not present |
| • | If the MIL is illuminated and then the engine stalls, the MIL
will remain illuminated so long as the ignition switch is ON. |
| • | If the MIL is not illuminated and the engine stalls, the MIL will
not illuminate until the ignition switch is cycled OFF, then ON. |
Powertrain On Board Diagnostic (OBD) System Check
Perform the Powertrain On Board Diagnostic (OBD) System Check, when
the following conditions are present:
| • | When the MIL does not turn ON when the ignition switch is turned
to the RUN position. See above for MIL Operation |
| • | When the MIL remains ON while the engine is running |
| • | When the MIL is flashing while the engine is running |
| • | When a driveability symptom is determined |
Charge Warning Indicator
The PCM controls the charge warning indicator. The instrument cluster
turns the indicator ON during the engine start up in order to perform a
bulb test. The PCM turns ON the indicator when an undervoltage (10.2 Volts)
or overvoltage (18.0 Volts) is detected.
Hot Coolant Indicator
The PCM continuously monitors the engine coolant temperature sensor.
The PCM controls Hot Coolant indicator during the following instances:
| • | At an engine coolant temperature of approximately 124° C (255°
F) |
| • | At a sender resistance of approximately 53 ohms |
Low Oil Level Indicator
The PCM controls the low oil level indicator. The PCM samples the oil
level once per ignition cycle, at power up only, if the criteria are met,
indicating that the oil has had sufficient time to drain into the oil pan
from the last power down. If the engine coolant temperature is greater
than 75° C (167° F) at power down, the PCM will sample the oil
level after 3 minutes have elapsed. If the engine coolant temperature
is less than 75° C (167° F) at power down, the PCM will look for
at least an 11° C (20° F) drop in the engine coolant temperature,
before sampling the oil level at power up.
Fuel Gauge
The Fuel Level Sensor consists of the following components: float, the
wire float arm, and the ceramic resistor card. The Fuel Level Sensor is
mounted on the Modular Fuel Sender Assembly and is used as an input to the
PCM. The PCM uses this information as a fuel level input for Various diagnostics.
The PCM controls the Fuel Gauge by grounding the Fuel Gauge Control circuit.
Tachometer
The tachometer displays the engine speed in RPM. The voltage pulses
are taken from the PCM and sent to the tachometer. The tachometer responds
to the frequency of the voltage pulses that increase with the engine speed.
The solid state circuits process the pulses into a signal that drives the
tachometer.
Speedometer
The vehicle speed sensor (VSS) is a gear driven permanent magnet generator
housed in the transaxle. The sensor generates a sine wave output with a frequency
proportional to the vehicle speed. The PCM converts the signal to an
output that switches to ground at a frequency of 4000 pulses per mile.
The signal CKT drives the speedometer and the odometer and is used by various
vehicle components.
PRNDL Indicator
The transmission range (TR) switch is part of the park/neutral position
(PNP) and back-up lamp switch assembly, which is externally mounted on the
transmission manual shaft. The TR switch contains four internal switches
that indicate the transmission gear range selector lever position. The PCM
supplies ignition voltage to each switch circuit. As the gear range selector
lever is moved, the state of each switch may change, causing the circuit
to open or close. An open circuit or switch indicates a high voltage signal.
A closed circuit or switch indicates a low voltage signal. The PCM detects
the selected gear range by deciphering the combination of the voltage signals.
The PCM compares the actual voltage combination of the switch signals to
a TR switch combination table stored in memory.
Change Oil Soon Indicator (Driver Information Display)
The PCM determines the amount of oil life from the various sensors and
inputs within the engine control system. When the PCM determines that an oil
life of 0% is present, the PCM turns ON the change oil soon indicator by supplying
ground.
