Wrangler 4WD L4-150 2.5L VIN P MFI (1998)
Fig. 7 Intake Air Temp. Sensor Location-Typical
IDLE AIR CONTROL (IAC) MOTOR-PCM OUTPUT
The Idle Air Control (IAC) motor is mounted on the throttle body (Fig. 7) and is controlled by the Powertrain Control Module (PCM).
The throttle body has an air control passage that provides air for the engine at idle (the throttle plate is closed). The IAC motor pintle protrudes
into the air control passage and regulates air flow through it. Based on various sensor inputs, the PCM adjusts engine idle speed by moving the
IAC motor pintle in and out of the air control passage. The IAC motor is positioned when the ignition key is turned to the On position.
A (factory adjusted) set screw is used to mechanically limit the position of the throttle body throttle plate. Never attempt to adjust the engine idle
speed using this screw. All idle speed functions are controlled by the PCM.
CIRCUIT OPERATION
The Powertrain Control Module (PCM) operates the idle air control motor through 4 circuits; K39, K40, K59, and K60. Each circuit connects to
separate cavities in the PCM connector.
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Circuit K39 connects to cavity A19 of the PCM
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Circuit K40 connects to cavity A11 of the PCM
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Circuit K59 connects to cavity A20 of the PCM
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Circuit K6O connects to cavity A10 of the PCM
Ignition Circuit Sense-PCM Input
IGNITION CIRCUIT SENSE-PCM INPUT
The ignition circuit sense input tells the Powertrain Control Module (PCM) the ignition switch has energized the ignition circuit. Refer to the
wiring diagrams for circuit information.
Ignition Coil-PCM Output
IGNITION COIL-PCM OUTPUT
System voltage from the Automatic Shutdown (ASD) relay is supplied to the ignition coil positive terminal. The Powertrain Control Module
(PCM) operates the ignition coil. Ignition timing is not adjustable. The PCM adjusts ignition timing to meet changing engine operating conditions.
NOTE: Refer Ignition System for additional information.
Intake Manifold Air Temperature Sensor- PCM Input
