Jeep Liberty KJ. Manual - part 1485

6. Press ENTER to transfer the secret key (the SKIM will send the secret key to the PCM).

7. Press Page Back to get to the Select System menu and select ENGINE, JTEC (diesel only), MISCELLANEOUS,

and SRI MEMORY CHECK.

8. The scan tool will ask, Is odometer reading between XX and XX? Select the YES or NO button on the scan tool.

If NO is selected, the scan tool will read, Enter Odometer Reading<From I.P. odometer>. Enter the odometer
reading from the Instrument Panel and press ENTER.

PROGRAMMING THE SKIM

1. Turn the ignition switch on (transmission in park/neutral).

2. Use the scan tool and select THEFT ALARM, SKIM then MISCELLANEOUS.

3. Select PCM REPLACED (GAS ENGINE).

4. Program the vehicle four-digit PIN into SKIM.

5. Select COUNTRY CODE and enter the correct country.

NOTE: Be sure to enter the correct country code. If the incorrect country code is programmed into SKIM,
the SKIM must be replaced.

6. Select YES to update VIN (the SKIM will learn the VIN from the PCM).

7. Press ENTER to transfer the secret key (the PCM will send the secret key to the SKIM).

8. Program ignition keys to SKIM.

NOTE: If the PCM and the SKIM are replaced at the same time, all vehicle keys will need to be replaced and
programmed to the new SKIM.

PROGRAMMING IGNITION KEYS TO THE SKIM

1. Turn the ignition switch on (transmission in park/neutral).

2. Use the scan tool and select THEFT ALARM, SKIM then MISCELLANEOUS.

3. Select PROGRAM IGNITION KEY’S.

4. Enter secured access mode by entering the vehicle four-digit PIN.

NOTE: A maximum of eight keys can be learned to each SKIM. Once a key is learned to a SKIM it (the key)
cannot be transferred to another vehicle.

If ignition key programming is unsuccessful, the scan tool will display one of the following messages:

Programming Not Attempted - The scan tool attempts to read the programmed key status and there are no keys
programmed into SKIM memory.

Programming Key Failed (Possible Used Key From Wrong Vehicle) - SKIM is unable to program key due to one of
the following:

•

faulty ignition key transponder

•

ignition key is programmed to another vehicle.

•

8 Keys Already Learned, Programming Not Done - SKIM transponder ID memory is full.

5. Obtain ignition keys to be programmed from customer (8 keys maximum).

6. Using the scan tool, erase all ignition keys by selecting MISCELLANEOUS and ERASE ALL CURRENT IGN.

KEYS.

7. Program all ignition keys.

Learned Key In Ignition - Ignition key transponder ID is currently programmed in SKIM memory.

8E - 152

ELECTRONIC CONTROL MODULES

REMOVAL

1. Disconnect negative battery cable.

2. Disconnect ECM electrical connectors (1).

3. Remove ECM bracket (3) to inner fender retaining

nuts (5).

4. Remove ECM (2) and bracket assembly from vehi-

cle.

5. Separate ECM from bracket.

INSTALLATION

1. Install ECM (2) on bracket (3).

2. Position ECM and bracket assembly in vehicle.

3. Install ECM bracket to inner fender retaining nuts

(5).

4. Connect ECM electrical connectors (1).

5. Connect negative battery cable.

ELECTRONIC CONTROL MODULES

8E - 153

MODULE-POWERTRAIN CONTROL

DESCRIPTION

PCM

The Powertrain Control Module (PCM) is located in
the engine compartment.

MODES OF OPERATION

As input signals to the Powertrain Control Module (PCM) change, the PCM adjusts its response to the output
devices. For example, the PCM must calculate different injector pulse width and ignition timing for idle than it does
for Wide Open Throttle (WOT).

The PCM will operate in two different modes: Open Loop and Closed Loop.

During Open Loop modes, the PCM receives input signals and responds only according to preset PCM program-
ming. Input from the oxygen (O2S) sensors is not monitored during Open Loop modes.

During Closed Loop modes, the PCM will monitor the oxygen (O2S) sensors input. This input indicates to the PCM
whether or not the calculated injector pulse width results in the ideal air-fuel ratio. This ratio is 14.7 parts air-to-1
part fuel. By monitoring the exhaust oxygen content through the O2S sensor, the PCM can fine tune the injector
pulse width. This is done to achieve optimum fuel economy combined with low emission engine performance.

The fuel injection system has the following modes of operation:

•

Ignition switch ON

•

Engine start-up (crank)

•

Engine warm-up

•

Idle

•

Cruise

•

Acceleration

•

Deceleration

•

Wide Open Throttle (WOT)

•

Ignition switch OFF

The ignition switch On, engine start-up (crank), engine warm-up, acceleration, deceleration and wide open throttle
modes are Open Loop modes. The idle and cruise modes, (with the engine at operating temperature) are Closed
Loop modes.

8E - 154

ELECTRONIC CONTROL MODULES

IGNITION SWITCH (KEY-ON) MODE

This is an Open Loop mode. When the fuel system is activated by the ignition switch, the following actions occur:

•

The PCM pre-positions the Idle Air Control (IAC) motor.

•

The PCM determines atmospheric air pressure from the MAP sensor input to determine basic fuel strategy.

•

The PCM monitors the engine coolant temperature sensor input. The PCM modifies fuel strategy based on this
input.

•

Intake manifold air temperature sensor input is monitored.

•

Throttle Position Sensor (TPS) is monitored.

•

The Auto ShutDown (ASD) relay is energized by the PCM for approximately three seconds.

•

The fuel pump is energized through the fuel pump relay by the PCM. The fuel pump will operate for approx-
imately three seconds unless the engine is operating or the starter motor is engaged.

•

The O2S sensor heater element is energized via the ASD or O2S heater relay. The O2S sensor input is not
used by the PCM to calibrate air-fuel ratio during this mode of operation.

ENGINE START-UP MODE

This is an Open Loop mode. The following actions occur when the starter motor is engaged.

The PCM receives inputs from:

•

Battery voltage

•

Engine Coolant Temperature (ECT) sensor

•

CranKshaft Position (CKP) sensor

•

Intake manifold Air Temperature (IAT) sensor

•

Manifold Absolute Pressure (MAP) sensor

•

Throttle Position Sensor (TPS)

•

Camshaft position sensor signal

The PCM monitors the crankshaft position sensor. If the PCM does not receive a crankshaft position sensor signal
within three seconds of cranking the engine, it will shut down the fuel injection system.

The fuel pump is activated by the PCM through the fuel pump relay.

Voltage is applied to the fuel injectors with the ASD relay via the PCM. The PCM will then control the injection
sequence and injector pulse width by turning the ground circuit to each individual injector on and off.

The PCM determines the proper ignition timing according to input received from the crankshaft position sensor.

ENGINE WARM-UP MODE

This is an Open Loop mode. During engine warm-up, the PCM receives inputs from:

•

Battery voltage

•

Engine Coolant Temperature (ECT) sensor

•

CranKshaft Position (CKP) sensor

•

Intake manifold Air Temperature (IAT) sensor

•

Manifold Absolute Pressure (MAP) sensor

•

Throttle Position Sensor (TPS)

•

Camshaft position sensor signal

•

Park/neutral switch (gear indicator signal—auto. trans. only)

•

Air conditioning select signal (if equipped)

•

Air conditioning request signal (if equipped)

Based on these inputs the following occurs:

•

The PCM adjusts engine idle speed through the IAC motor and adjusts ignition timing.

•

The PCM operates the A/C compressor clutch through the A/C compressor clutch relay. This is done if A/C has
been selected by the vehicle operator and specified pressures are met at the high and low–pressure A/C
switches. Refer to Heating and Air Conditioning for additional information.

ELECTRONIC CONTROL MODULES

8E - 155

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