Mitsubishi Montero (1998+). Manual - part 39

this information to control solenoids on transmission valve body. TCM

controls transmission shifting and torque converter lock-up.

         TCM contains a self-diagnostic system, which will store

Diagnostic Trouble Codes (DTC) if failure or problem exists in

electronic control system. DTC can be retrieved to determine problem

area. See SELF-DIAGNOSTIC SYSTEM. TCM is located under left side of

instrument panel, left of steering column. See  Fig. 1.

         TCM INPUT DEVICES

         Brakelight Switch Signal

         Brakelight switch delivers input signal to TCM, indicating

vehicle braking. Brakelight switch is located on brake pedal support.

         Cruise Control Electronic Control Unit (ECU)

         Cruise control ECU delivers an input signal to control

overdrive operation in accordance with vehicle speed when cruise

control is operating. When in overdrive with cruise control on, if

vehicle speed drops 2 MPH less than the set speed, overdrive is

released to prevent reduction in vehicle speed. Once vehicle speed is

more than the set speed, overdrive function is resumed. If coolant

temperature is low, transmission will not shift into overdrive. Cruise

control ECU is located below center A/C vent, behind temperature

control panel on Montero. On Montero Sport, cruise control ECU is

located behind driver’s kick panel.

         Engine Coolant Temperature Sensor (ECT) Signal

         Engine coolant temperature sensor delivers input signal to

TCM, indicating engine coolant temperature. Coolant temperature sensor

is located on engine.

         Input & Output Shaft Speed Sensors

         Sensors are magnetic pick-ups that monitor input and output

shaft speeds. AC waveforms are input to TCM by sensors. Sensors are

located on front and rear side of transmission case.

         OD Switch Signal

         The OD switch provides an input signal to TCM to indicate

when overdrive is selected by operator. When OD switch is depressed to

ON position, transmission will shift into 4th gear when shift lever is

in "D" position, and OD OFF light on instrument panel will go off.

When OD switch is released to OFF position, transmission will shift

into 3rd gear, and OD OFF light on instrument panel will come on. The

OD switch is mounted on shift lever.

         Oil Temperature Sensor Signal

         Oil temperature sensor provides TCM with ATF temperature

values. TCM uses this information to control shift points for maximum

performance. If transmission oil temperature exceeds standard values,

instrument panel ATF - TEMP light will come on. Sensor is mounted to

cooler line at transmission.

         Park/Neutral Position (PNP) Switch Signal

         PNP switch delivers an input signal to TCM indicating shift

lever position. Switch is located on side of transmission.

         Throttle Position (TP) Sensor Signal

         TP sensor delivers closed throttle and variable throttle

position input signals to TCM. TP sensor is located on side of

throttle body.

         4WD Low Range Detection Switch

         4WD low range detection switch provides information to TCM

when transfer case is in 4WD low-lock range.

Fig. 1:  Locating Transmission Control Module (Montero)

Courtesy of Mitsubishi Motor Sales of America.

Fig. 2:  Locating Transmission Control Module (Montero Sport)

Courtesy of Mitsubishi Motor Sales of America.

         TCM OUTPUT DEVICES

         Shift Solenoids No. 1 & No. 2

         TCM controls transmission shifting by delivering an output

signal to operate proper solenoid. Solenoids are located on

transmission valve body. See Fig. 3. Solenoids are operated in

accordance with shift lever range. If a solenoid malfunctions, TCM may

select a preselected gear. See Fig. 4.

NOTE:    TCM provides a fail-safe system which will place transmission

         in preselected gear depending on solenoid failure. In other

         gears, fail-safe system will not be activated and

         transmission will be placed in a specified gear. See

         Fig. 4.

         Lock-Up Solenoid

         TCM controls torque converter lock-up by delivering an output

signal to lock-up solenoid. Lock-up solenoid is activated when shift

lever is in "D" position and vehicle is at specified speed. Solenoid

is located on transmission valve body. See  Fig. 3.

Fig. 3:  Locating Lock-Up & Shift Solenoids

Courtesy of Mitsubishi Motor Sales of America.

Fig. 4:  Checking Operation Of Shift Solenoids No. 1 & No. 2

Courtesy of Mitsubishi Motor Sales of America.

         SELF-DIAGNOSTIC SYSTEM

         SYSTEM DIAGNOSIS

NOTE:    Before testing transmission, ensure fluid level is correct

         and throttle and shift cables are properly adjusted. Ensure

         engine starts with shift lever in Park and Neutral to ensure

         proper adjustment of park/neutral position switch.

         Transmission must first be tested by checking for stored

         codes. See RETRIEVING DIAGNOSTIC TROUBLE CODES (DTC).

         TCM monitors transmission operation and contains a self-

diagnostic system which stores a DTC if an electronic control system

failure or problem exists. If a problem exists in any of the solenoids

or speed sensors and a DTC is set, TCM delivers a signal to blink the

ATF TEMP light on instrument panel to warn the driver. DTC may be set

if a failure exists and can be retrieved for transmission diagnosis.

         RETRIEVING DIAGNOSTIC TROUBLE CODES (DTC)

NOTE:    Before retrieving DTC, ensure proper battery voltage exists

         for proper self-diagnosis system operation. DO NOT disconnect

         battery or ECM connectors before retrieving DTC.

         Retrieving Codes Using Scan Tool

         Ensure ignition switch is in OFF position. Connect scan tool

to Data Link Connector (DLC). See Fig. 5. Turn ignition switch to ON

position. Check for stored DTC and record code(s). See DIAGNOSTIC

TROUBLE CODE IDENTIFICATION table.