Jeep WJ Grand Cherokee Electronic Control Modules

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1. BCM – Body Control Module
2. PDM – Passenger Door Module
3. AM – Airbag Control Module
4. MIC – Mechanical Instrument Cluster
5. EVIC – Electronic Vehicle Information Center
6. CAB – Controller Antilock Brakes
7. TCM – Transmission Control Module
8. SKIM – Sentry Key Immobilizer Module
9. HSM – Heated Seat Module
10. MHSM – Memory Heated Seat Module
11. DDN – Driver Door Module
12. PCM – Powertrain Control Module
13. SM – Sunroof Module
14. RSM – Rain Sense Module
15. APM – Adjustable Pedals Module

Module Name Location Function
1. Body Control Module BCM Attached to the Junction Block, under the driver’s side of the instrument panel. The BCM utilizes integrated circuitry and information carried on the Programmable Communications Interface (PCI) data bus network along with many hard wired inputs to monitor many sensor and switch inputs throughout the vehicle.The BCM supports many body electrical features such as Interior Lighting, Exterior Lighting, Intermittent Wipers, Remote Radio, Accessory Delay, and Heated Seats.
2. Passenger Door Module PDM Behind the right door trim panel, integrated within the door switch assembly. The Door Modules control various electronic features such as power door locks, power windows, power mirrors, courtesy lighting, and the liftgate lock motor.
3. Airbag Control Module ACM Underneath center console housing, behind the shifter assembly. The microprocessor in the Airbag Control Module contains the supplemental restraint system logic circuits and controls all of the supplemental restraint system components.
4. Mechanical Instrument Cluster MIC Left dashboard The Mechanical Instrument Cluster (MIC) provides gauge and indicator control. The MIC utilizes the PCI Bus to obtain most, but not all, of the information needed to control the gauges and indicators.
5. Electronic Vehicle Information Center EVIC Within overhead console Compass, temperature, trip computer, information center (EVIC).
6. Controller Antilock Brakes CAB Attached to the Hydraulic Control Unit (HCU) under the hood, in front of the Master Cylinder. Controls the Teves Mark 20e ABS. Also controls Electronic Brake Distribution (EBD), an electronically controlled proportioning valve.
7. Transmission Control Module (45RFE Only) TCM Right (passenger) side of the engine compartment near the firewall, mounted to the inner fender. The Transmission Control Module controls all electronic operations of the transmission. The TCM receives information regarding vehicle operation from both direct and indirect inputs, and selects the operational mode of the transmission. Based on the information received from these various inputs, the TCM determines the appropriate shift schedule and shift points, depending on the present operating conditions and driver demand. This is possible through the control of various direct and indirect outputs.
8. Sentry Key Immobilizer Module SKIM Under the steering column opening cover, attached to the bottom side of the steering column housing. The Sentry Key Immobilizer Module contains a Radio Frequency (RF) transceiver and a microprocessor. The SKIM transmits RF signals to, and receives RF signals from the Sentry Key transponder through a tuned antenna ring integral to the SKIM housing. When the ignition switch is turned to the On position, the SKIM transmits an RF signal to the transponder in the ignition key. The SKIM then waits for an RF signal response from the transponder. If the response received identifies the key as valid, the SKIM sends a valid key message to the PCM over the PCI data bus. If the response received identifies the key as invalid, or if no response is received from the key transponder, the SKIM sends an invalid key message to the PCM. The PCM will enable or disable engine operation based upon the status of the SKIM messages.
9. Memory Heated Seat Module MHSM Under the driver’s seat, mounted on a bracket that is located between the power seat track and the seat cushion frame. Performs memory seat functions and heated seat functions.
10. Heated Seat Module HSM Under the driver’s seat, mounted on a bracket that is located between the power seat track and the seat cushion frame. Performs heated seat functions.
11. Driver Door Module DDM Behind the left door trim panel, integrated within the door switch assembly. The Door Modules control various electronic features such as power door locks, power windows, power mirrors, courtesy lighting, and the liftgate lock motor.
12. Powertrain Control Module PCM
(JTEC)
On the cowl panel, right rear side of the engine compartment. The PCM is a pre-programmed, triple microprocessor digital computer. It regulates ignition timing, air-fuel ratio, emission control devices, charging system, certain transmission features, speed control, air conditioning compressor clutch engagement and idle speed. The PCM can adapt its programming to meet changing operating conditions.
13. Sunroof Module SM In the overhead console as part of the sunroof assembly Controls operation of the sunroof Open, Close and Vent functions.
14. Rain Sense Module RSM Inside of the windshield, between the rear view mirror mounting button and the windshield header, concealed behind a molded plastic trim cover that snaps over the module housing. The microprocessor-based Rain Sensor Module senses moisture in the wipe pattern on the outside of the windshield glass and sends wipe commands to the Body Control Module (BCM). Four InfraRed (IR) diodes within the RSM generate IR light beams that are aimed by four of the convex optical lenses near the base of the module through the windshield glass. Four additional convex optical lenses near the top of the RSM are focused on the IR light beams on the outside of the windshield glass and allow the two photocells within the module to sense changes in the intensity of these IR light beams. When sufficient moisture accumulates within the wipe pattern of the windshield glass, the RSM detects a change in the monitored IR light beam intensity.
15. Adjustable Pedals Module APM Under dash above brake pedal. Controls operation of the adjustable pedals.
All vehicle communications are carried out across the single wire Programmable Communications Interface (PCI) Bus.