Wrangler 4WD L4-150 2.5L VIN P MFI (1998)
The battery voltage input provides power to the Powertrain Control Module (PCM). It also informs the PCM what voltage level is supplied to the
ignition coil and fuel injectors.
If battery voltage is low, the PCM will increase injector pulse width (period of time that the injector is energized). This is done to compensate for
the reduced flow through injector caused by the lowered voltage.
FIVE VOLT SENSOR SUPPLY-PRIMARY
Supplies the required 5 volt power source to the crankshaft position sensor, cam shaft position sensor, MAP sensor and throttle position sensor
FIVE VOLT SENSOR SUPPLY-SECONDARY
Supplies the required 5 volt source to the vehicle speed sensor.
Brake Switch-PCM Input
BRAKE SWITCH-PCM INPUT
When the brake light switch is activated, the Powertrain Control Module (PCM) receives an input indicating that the brakes are being applied.
After receiving this input, the PCM maintains idle speed to a scheduled rpm through control of the Idle Air Control (IAC) motor. The brake switch
input is also used to operate the speed control system.
Camshaft Position Sensor-PCM Input
CAMSHAFT POSITION SENSOR-PCM INPUT
Fig. 3 Camshaft Position Sensor-Typical
A sync signal is provide by the camshaft position sensor located in the distributor (Fig. 3). The sync signal from this sensor works in conjunction
with the crankshaft position sensor to provide the Powertrain Control Module (PCM) with inputs. This is done to establish and maintain correct
injector firing order Refer to Camshaft Position Sensor in Ignition System for more information.
CCD Bus (+/-) Circuits-PCM Outputs
CCD (Information) BUS
Also called Chrysler Collision Detection (CCD (Information)) Bus. Several systems communicate with each other using the CCD (Information)
Bus.
AIRBAG SYSTEM
The airbag system is designed to provide increased driver and passenger protection if the vehicle is involved in a front-end collision. The system is
most effective when used in conjunction with the seat belt system. The ACM is an electronically-triggered system that uses only its own internal
electronic sensor to trigger the airbags.
Whenever the ignition key is turned to the "run" or "start" position, the airbag control module (ACM) performs a lamp check by turning the
AIRBAG warning lamp on. The lamp stays lit for 6 to 8 seconds, then goes off. If the lamp remains oft, it means that the ACM has checked the
system and found it to be free of discernible malfunctions. The airbag system is monitored by the ACM.
The ACM monitors critical input and output circuits within the airbag system, making sure they are operating correctly. Some circuits are tested
continuously; others are checked only under certain circumstances. The ACM provides diagnostic information about the airbag system to the
technician through the DRB via the CCD bus.
