Wrangler 4WD L4-150 2.5L VIN P MFI (1998)
Intake Manifold Air Temperature Sensor
INTAKE MANIFOLD AIR TEMPERATURE SENSOR - PCM INPUT
The intake manifold air temperature sensor is installed in the intake manifold with the sensor element extending into the air stream. The sensor
provides an input voltage to the Powertrain Control Module (PCM) indicating intake manifold air temperature. The input is used along with inputs
from other sensors to determine injector pulse width. As the temperature of the air-fuel stream in the manifold varies, the sensor resistance
changes. This results in a different input voltage to the PCM.
Leak Detection Pump (Switch) Sense-PCM Input
Provides an input to the Powertrain Control Module (PCM) that the leak detection pump (LDP) has been activated. Refer to Emission Control Systems
for LDP information.
Leak Detection Pump-PCM Output
Certain engines with certain emissions packages are equipped with a leak detection pump (LDP). The LDP is activated through this PCM output. Refer
to Emission Control Systems for additional information.
Malfunction Indicator Lamp-PCM Output
MALFUNCTION INDICATOR LAMP-PCM OUTPUT
Fig. 12 Check Engine Lamp Typical
The malfunction indicator lamp illuminates each time the ignition key is turned on. It will stay on for approximately three seconds as a bulb test.
The lamp is displayed on the instrument panel as the CHECK ENGINE lamp (Fig. 12).
The signals needed to activate the lamp are sent from the Powertrain Control Module (PCM) to the instrument panel through the CCD
(Information) bus circuits.
If the PCM receives an incorrect signal, or no signal from certain sensors or emission related systems, the lamp is turned on. This is a warning that
