Multiplex Control Systems: Overview Mitsubishi Montero III

Central Door Locking System Operation

1. When the driver's inside lock knob is locked or unlocked, the lock relay inside the ETACS-ECU turns on to lock or unlock all doors.
2. With all the doors locked, turning the key in the driver's door unlocks the door. Turning it again makes the door unlock relay close to send a signal for unlocking all doors.
3. When the door lock switch (built into the power window switch) is operated, the lock or unlock relay inside the ETACS-ECU is turned on to lock or unlock all doors.

Power Window Relay Operation

If the ignition switch is turned to "ON" position, the power window relay is energized to activate the power windows.

Sunroof Operation

1. All of the slide open/close, tilt up/down, and stop operations can be performed by a single switch.
2. When the roof lid glass is tilted up, the sunshade opens approximately 98 mm (3.9 inches) in combined operation with the roof lid glass for better ventilation.
3. A jam preventing mechanism has been adopted. When a slide-close or tilt-down operation is blocked by an external force, the roof lid glass moves back and stops.
4. The electronic sunroof system cannot be operated manually. The sunroof wrench that was used in previous models is not provided. If the anti-jam mechanism reverses the sunroof five or more times consecutively due to deformation or other problem with the sunroof components, it deactivates and allows the sunroof to make small movements [30 mm (1.2 inches)] until it closes completely.

Windshield Low-speed (and High-speed) Wiper Operation

1. If the windshield low-speed wiper switch is turned to the ON position with the ignition switch at the "ACC" or "ON" position, the column switch sends a low-speed wiper ON and high-speed wiper OFF signals to the front-ECU. This turns the wiper signal on and the wiper speed switching relay off (low-speed), causing the wipers to operate at low-speed.
2. If the windshield high-speed wiper switch is turned to the ON position, the column switch sends a low-speed wiper OFF and high-speed wiper ON signals to the front-ECU. This turns both the wiper signal and the wiper speed switching relay on (high-speed), causing the wipers to operate at high-speed.

Windshield Intermittent Wiper Operation

The ETACS-ECU calculates the wiper operation interval according to the voltage signal sent from the column switch. Then the ETACS-ECU sends a signal to the front-ECU. The front-ECU determines the wiper operation interval and turns on the wiper relay signal relay. This causes the wiper auto stop relay to turn on. Then the wiper auto stop relay will turn off after the wipers reach the park position. This causes the wiper signal relay and then the wipers to turn off. If the wiper signal relay remains off for the wiper operation interval, the relay turns on again, causing the wipers to operate in intermittent mode.

Windshield Mist Wiper Operation

1. If the windshield mist wiper switch is turned to the ON position with the ignition switch at the "ACC" or "ON" position, the mist wiper high-speed operation signal is sent to the front-ECU. This signal turns on the wiper speed switching relay, causing the wipers to work at high-speed while the mist switch is on.
2. While the windshield mist wiper switch remains turned on when the intermittent mode is still working, the wipers work as the mist wiper. However, the wipers return to the intermittent mode again when the switch is changed back to "INT" position.
3. To prevent the windshield mist wiper from operating when the windshield wiper switch is turned OFF, the windshield mist wiper does not work for 0.5 second after the windshield intermittent wiper switch, the windshield low-speed wiper switch and the windshield high speed wiper switch are turned OFF.

Windshield Washer Operation

1. If the windshield washer switch is turned to ON position with the ignition switch at "ACC" or "ON" position, the windshield washer ON signal is sent to the front-ECU, causing the windshield wiper signal to turn on after 0.3 seconds. After the windshield washer switch signal turns off, the windshield wiper signal turns off in three seconds.
2. If the windshield washer switch is turned on while the windshield wiper is at intermittent mode, when the windshield washer switch is turned OFF within 0.2 second, the wiper works only once to perform mist operation by the windshield washer switch. When the ON condition of the windshield washer switch continues more than 0.2 second, the wiper performs the same movement as normal condition from the time when 0.2 second has elapsed and then returns to the intermittent motion.

Rear Wiper Operation

If the rear wiper and washer switch is turned to "INT" position with the ignition switch at "ACC" or "ON" position, the ETACS-ECU turns ON the rear wiper drive signal for three seconds (approx. two cycles), then 7.4 seconds later the intermittent motion operates every eight seconds. If the selector lever is moved to the "R" position when the rear wiper and washer switch is turned to the "INT" position and the ignition switch is at the "ACC" or "ON" position, the park/neutral position switch "R" turns ON. One second later, the ETACS-ECU turns ON the rear wiper drive signal for three seconds (approx. two cycles). Then, 7.4 seconds later, the intermittent motion of eight seconds' cycle is restored.

Rear Washer Operation

If the rear wiper and washer switch is turned to the ON (washer) position with the ignition switch at the "ACC" or "ON" position, the rear washer ON signal is sent to the ETACS-ECU, causing the rear wiper signal to turn on after 0.3 seconds. After the rear washer switch signal turns off, the rear wiper signal turns off in three seconds. If the rear washer switch is turned to the ON position while the rear wiper is in intermittent mode, the rear washer works for that period when the washer switch remains on. Then the rear wipers return to the intermittent mode.

Theft-alarm System Operation

If a door, back door or hood is opened, when the theft-alarm system has been armed the horn (theft-alarm horn and horn) will sound and headlights flash (high-beam) intermittently for a period of 180 seconds.

TECHNICAL DESCRIPTION (COMMENT)

The SWS monitor kit may be connected improperly.

CIRCUIT DIAGRAM & CONNECTOR IDENTIFICATION

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 1

Scheme 2

CIRCUIT OPERATION

1. The power supply to the column switch is provided by the battery and the ignition switch (IG1).
2. If the power supply system from the battery is defective, the system operates by the power supply from the ignition switch (IG1).

The power supply circuit to the column switch (column-ECU) may be defective. If the battery power supply circuit (terminal No.1 of the column switch) to the ECU is damaged, also check the power supply circuit from the ignition switch (IG1) (terminal No.9 of the column switch), and repair if necessary.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 3

Scheme 4

1. The power supply to the ETACS-ECU is provided by the battery and the ignition switch (IG1).
2. If the power supply system from the battery is defective, the system operates by the power supply from the ignition switch (IG1).

It is suspected that the power supply circuit to the ETACS-ECU is defective, or the wiring harness between the SWS monitor kit and the ETACS-ECU or their connector(s) is damaged. If the battery power supply circuit to the ECU (terminal No.6 of the ETACS-ECU) is damaged, also check the power supply circuit from the ignition switch (IG1) (terminal No. 16 of the ETACS-ECU), and repair if necessary. If the ground circuit to the ECU (terminal No.20 of the ETACS-ECU) is damaged, also check the ground circuit to the sensor (terminal No.23 of the ETACS-ECU), and repair if necessary.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 5

Scheme 6

1. The power supply to the front-ECU is provided by the battery and the ignition switch (IG2).
2. If the power supply system from the battery is defective, the system operates by the power supply from the ignition switch (IG2).

It is suspected that the power supply circuit to the front-ECU is defective, or the wiring harness between the SWS monitor kit and the front-ECU or their connector(s) is damaged. If the battery power supply circuit to the ECU (terminal No.7 of the front-ECU) is damaged, also check the power supply circuit from the ignition switch (IG2) (terminal No.30 of the front-ECU), and repair if necessary.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 7

Scheme 8

1. Power to the sunroof motor assembly is supplied through fusible links (2) and (4).
2. When the ignition switch (IG2) signal is on, the sunroof motor assembly is ready to operate.

The power supply circuit or the communication circuit to the sunroof motor assembly or the sunroof motor assembly may be defective.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 9

The RV meter or its power supply circuit or communication circuit may be defective.

The ETACS-ECU operates the ignition key reminder tone alarm function, based on input signals from the following switches

1. Ignition switch (IG1)
2. Key reminder switch
3. Driver's door switch

If the function does not work normally, the input circuit system from the switches or the ETACS-ECU may be defective, see CIRCUIT OPERATION .

The ETACS-ECU operates the light reminder tone alarm function (sounds continuously) according to the following signals

1. Ignition switch (IG1)
2. Driver's door switch
3. Taillight switch
4. Headlight switch

The ETACS-ECU operates the light reminder tone alarm function (sounds continuously) under the following conditions

1. Ignition switch: LOCK position (key inserted)
2. Driver's door: OPEN

If the function does not work normally, the input circuit system from the switches or the ETACS-ECU may be defective, see CIRCUIT OPERATION .

The ETACS-ECU operates the seat belt tone alarm function according to signals from the following switches

1. Ignition switch (IG1)
2. Driver's seat belt switch

If the function does not work normally, the input circuit system from the switches or the ETACS-ECU may be defective, see CIRCUIT OPERATION .

The ETACS-ECU sound a tone alarm when the RV meter sends a sound request signal to the ECU.

If this function does not work normally, the RV meter, the ETACS-ECU or their communication circuit may be defective.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 10

Scheme 11

1. The ETACS-ECU operates the central door lock system according to the following signals: Driver's or passenger's door lock actuator switch Driver's or passenger's door lock key cylinder switch Door lock switch, which is incorporated in the power window main switch or power window sub switch (front RH) The ETACS-ECU locks or unlocks all the doors by operating the central door lock relay (incorporated in the ECU) in response to input signals.

1. The ETACS-ECU operates the central door lock system according to the following signals: Driver's or passenger's door lock actuator switch Driver's or passenger's door lock key cylinder switch Door lock switch, which is incorporated in the power window main switch or power window sub switch (front RH)
2. The ETACS-ECU locks or unlocks all the doors by operating the central door lock relay (incorporated in the ECU) in response to input signals.

The wiring harness between the door lock actuator or the ETACS-ECU and the door lock actuator may defective.

The door lock switch (built into the power window switch) or the ETACS-ECU may be defective.

The door lock switch (built into the power window switch) or the ETACS-ECU may be defective.

TECHNICAL DESCRIPTION

The driver's or front passenger's door lock actuator switch or the ETACS-ECU may be defective.

The ETACS-ECU operates the forgotten key prevention function according to the following switches

1. Key reminder switch
2. Driver's or passenger's door switch
3. Driver's or passenger's door lock actuator switch

If the function does not work normally, the input circuit system from the switches or the ETACS-ECU may be defective, see CIRCUIT OPERATION .

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 12

Scheme 13

The ETACS-ECU turns on the power window relay (installed on the junction block) to activate the power windows when the ignition switch (IG1) is turned to the "ON" position.

The ETACS-ECU operates the power window timer function according to the following signals

1. Ignition switch (IG1)
2. front door switch

If the power window timer function does not work normally, its input circuit, the ETACS-ECU or the front-ECU may be defective.

The front power window motor (LH) opens or closes the door window (LH) when the power window main switch is moved to "UP" or "DOWN" position.

The power window main switch or the front power window motor (LH) may be defective.

Power window motors open or close the door windows when the front passenger's or rear passenger's sub switch is moved to "UP" or "DOWN" position.

A power window sub-switch or power window motor may be defective. Alternatively, the power window lock switch (incorporated in the power window main switch) may remain pressed to "LOCK" position.

When you operate each power window switch for front or rear passengers (incorporated in the power window main switch), the corresponding power window motor operates, thus causing each power window to close or open.

If the corresponding power window opens and closes normally when each power window sub-switch is operated, the power window main switch may be defective.

A receiver is incorporated in the ETACS-ECU. This receiver receives a lock or unlock signal from the transmitter.

The ETACS-ECU operates the following functions when it receives lock or unlock signal from the transmitter

1. Dome light answerback function
2. Turn-signal light answerback function
3. Horn answerback function

The turn-signal lights and horn answerback functions can be disabled or enabled. However, the dome light answerback function can not be disabled.

The ETACS-ECU operates the encrypted code register mode according to the following signals

1. Key reminder switch
2. Hazard warning light switch

Is the encrypted code register mode can not be set, the input circuits from the switches described in "CIRCUIT OPERATION" or the ETACS-ECU may be defective.

If the encrypted code register mode can be set but the transmitter can not be registered, the transmitter or the ETACS-ECU may be defective.

1. The sunroof motor assembly is energized through fusible links 2 and 4 by the battery.
2. When the ignition switch (IG2) signal is on, the sunroof motor assembly is ready to operate.

The sunroof switch or the sunroof motor assembly may be defective.

1. The sunroof timer function works according to the signals from the following switches: Ignition switch (IG1): OFF Front door switch: OFF
2. Vehicle condition Ignition switch: LOCK position Driver's and front passenger's door: Closed
3. When a front door is opened and closed while the sunroof timer function is on, the sunroof operative duration will be changed.

Is the sunroof timer function does not work normally, the input circuits from the switches described in "CIRCUIT OPERATION", the sunroof motor assembly, the ETACS-ECU or the SWS communication line may be defective.

The sunroof motor assembly monitors load condition according to the current, which runs in the motor. If a predetermined current is exceeded, the sunroof motor reverses due to safety mechanism. If the sunroof motor does not reverse when an excessive load is applied, the sunroof motor assembly may be defective.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 14

Scheme 15

1. The windshield wiper and washer switch sends a signal through the column-ECU (incorporated in the column switch) to the front-ECU. If the column-ECU sends a windshield wiper and washer switch "ON" signal to the front-ECU, the front-ECU turns on the relay (incorporated in the front-ECU), thus causing the windshield wiper and washer motor to be turned on.
2. If the SWS communication line is defective, the front-ECU operates windshield wiper motor by using the other communication lines (wiper backup circuit) instead of that line. In this case, the windshield wiper works at low speed regardless of the windshield wiper and washer switch positions ("LO" or "HIGH").

If the windshield wiper does not work at all, the windshield wiper motor, column switch (windshield wiper and washer switch) or the front-ECU may be defective.

The system may be at fail-safe mode as the SWS communication line is defective.

If the system can not receive any signal from the column switch (windshield wiper and washer switch) due to a open circuit in the SWS communication line or other reasons, the system will enter the fail-safe mode when the ignition switch is at the "ACC" position.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 16

If either of the windshield wiper switch positions is defective, the windshield wiper motor, column switch (windshield wiper and washer switch) or the front-ECU may be defective.

If the windshield wiper does not stop at predetermined park position, the windshield wiper motor or the front-ECU may be defective.

If the windshield intermittent wiper interval is not changed by operating the windshield intermittent wiper interval adjusting knob or according to the vehicle speed, the column switch, the ETACS-ECU or the front-ECU may be defective.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 17

Scheme 18

The windshield washer switch sends a signal through the column-ECU (incorporated in the column switch) to the front-ECU. If the column-ECU sends a windshield washer switch "ON" signal to the front-ECU, the front-ECU turns on the relay (incorporated in the front-ECU), thus causing the windshield washer motor to be turned on.

If the windshield washer does not work normally, the windshield washer motor, the column switch (windshield wiper and washer switch) or the front-ECU may be defective.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 19

Scheme 20

1. The rear wiper switch sends a signal through the column-ECU (incorporated in the column switch) to the ETACS-ECU. If the column-ECU sends a rear wiper switch "ON" signal to the ETACS-ECU, the ETACS-ECU turns on the relay (incorporated in the ETACS-ECU), thus causing the rear wiper motor to be turned on.
2. The ETACS-ECU operates the rear wiper according to the following switches: Ignition switch (ACC) Rear wiper switch

If the rear wiper does not work normally, the input circuit system from the switches, the rear wiper motor, the column switch (windshield wiper and windshield washer switch) or the ETACS-ECU may be defective, see CIRCUIT OPERATION .

If the rear wiper does not stop at predetermined park position, the rear wiper motor or the ETACS-ECU may be defective.

The ETACS-ECU operates the rear wiper consecutively approximately twice when the selector lever is moved to "R" position while the rear wiper is turned on.

If the rear wiper does not work consecutively approximately twice, the park/neutral position switch ("R" position) or the ETACS-ECU may be defective.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 21

Scheme 22

The rear washer switch sends a signal through the column-ECU (incorporated in the column switch) to the ETACS-ECU. If the column-ECU sends a rear washer switch "ON" signal to the ETACS-ECU, the ETACS-ECU turns on the relay (incorporated in the ETACS-ECU), thus causing the rear washer motor to be turned on.

If the rear washer does not work normally, the rear washer motor, the column switch (windshield wiper and washer switch) or the front-ECU may be defective.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 23

Scheme 24

1. The headlight washer switch sends a signal through the column-ECU (incorporated in the column switch) to the front-ECU.
2. The front-ECU switches on its relay for 0.5 seconds if it receives a signal through the column-ECU from the headlight washer switch while the ignition switch is at the "ACC" or "ON" position. Then the headlight washer system works.

If the headlight washer system does not work normally, the headlight washer motor, the front-ECU, the column switch or the ETACS-ECU may be defective.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 25

Scheme 26

1. The ETACS-ECU operates the seat belt warning light according to the following switch signals: Ignition switch (IG1) Driver's seat belt switch
2. If the driver turn the ignition switch to the "ON" position without fastening the seat belt, the seat belt warning light illuminates.

If the seat belt warning light does not illuminate, the input circuit, the combination meter (seat belt warning light bulb or printed-circuit board) or the ETACS-ECU may be defective.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 27

1. When the driver's door is opened with the ignition switch at "ACC" position, the ETACS-ECU illuminates the ignition key hole illumination light.
2. The ignition key hole illumination light goes out in 30 seconds after the driver's door is closed. The ignition key hole illumination light remains illuminated for 30 seconds after the ignition key is pulled out.
3. The ETACS-ECU operates the ignition key hole illumination light according to the input signals from the following switches: Ignition switch (IG1): OFF Key reminder switch: OFF
4. Vehicle condition Ignition switch: ACC position
5. Ignition key is inserted in the ignition key cylinder

Is the ignition key hole illumination light does not illuminate, the input circuits from the switches described in "CIRCUIT OPERATION", the key reminder switch (ignition key hole illumination light bulb) or the ETACS-ECU may be defective.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 28

When the lighting switch is set to "TAIL" position, the "TAIL" signal is sent through the column-ECU (incorporated in the column switch) to the front-ECU. IF the front-ECU receives the "TAIL" signal through the column-ECU, the front-ECU turns on the tail light relay (incorporated in the front-ECU), thus causing the tail lights to illuminate.

If the tail lights do not illuminate normally, the column switch or the front-ECU may be defective.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 29

1. When the lighting switch is set to "HEAD" position, the "HEAD" signal is sent through the column-ECU (incorporated in the column switch) to the front-ECU. If the front-ECU receives the "HEAD" signal through the column-ECU, the front-ECU turns on the headlight relay (incorporated in the front-ECU), thus causing the headlights to illuminate. The headlights always illuminate at low-beam by the headlight dimmer switch automatic resetting function.
2. If the SWS communication line is defective, the front-ECU operates the headlights by using the other communication lines (headlight backup circuit) instead of that line.

If the headlights (low-beam) do not illuminate normally, the column switch or the front-ECU may be defective.

When the dimmer switch is turned on, the column switch sends a signal to the front-ECU. Then the front-ECU switches the headlights from low-beam to high beam or vice versa.

If the headlights (high beam) do not illuminate normally, the column switch or the front-ECU may be defective.

If both of the headlights (low-beam and high-beam) do not illuminate, the input circuit from the passing switch or the front-ECU may be defective.

If the headlights illuminate at low-beam regardless of the lighting switch positions, the headlight operation is in fail-safe mode.

If the position lights, the tail lights, the side marker lights or the license plate lights do not illuminate, their bulb may be defective.

If one of the headlights does not illuminate, a headlight bulb may be defective.

If the high-beam indicator light does not illuminate, the high-beam indicator light bulb or the ETACS-ECU may be defective.

The ETACS-ECU operates the headlight automatic shutdown function according to the following signals

1. Ignition switch (IG1)
2. Driver's door switch
3. Tail light switch
4. Headlight switch

If the function does not work normally, the input circuit system from the switches, the ETACS-ECU or the front-ECU may be defective, see CIRCUIT OPERATION .

The headlight dimmer switch automatic resetting function is controlled by the front-ECU.

If the headlight dimmer switch automatic resetting function does not work normally, the front-ECU may be defective.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 30

Scheme 31

1. The turn-signal light switch sends a signal through the column-ECU (incorporated in the column switch) to the ETACS-ECU. If the column-ECU sends a turn-signal light switch "ON" signal to the ETACS-ECU, the ETACS-ECU turns on the flasher timer (incorporated in the ETACS-ECU), thus causing the turn-signal lights to flash.
2. The ETACS-ECU operates the turn-signal lights according to the following signals
3. Ignition switch (IG1)
4. Turn-signal light switch

Is the turn-signal lights do not flash normally, the input circuits from the switches described in "CIRCUIT OPERATION" or the ETACS-ECU may be defective. If the hazard warning lights do not flash, the power supply line to the ETACS-ECU (dedicated to the turn-signal lights) may be defective.

If the ETACS-ECU receives "ON" signal from the hazard warning light switch, the ETACS-ECU turns on the flasher timer (incorporated in the ETACS-ECU), thus causing the turn-signal lights to flash.

If the hazard warning lights do not flash, the power supply line to the ETACS-ECU (dedicated to the turn signal lights) or the ETACS-ECU may be defective.

If the right or left turn-signal light does not illuminate, their bulb may be defective.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 32

Scheme 33

1. The ETACS-ECU sends a fog light illumination request signal ("LIGHT ON" signal) to the front-ECU when the fog light switch is turned on while the headlights are on.
2. Then the front-ECU switches on its relay to illuminate the fog lights.

If the headlights illuminate normally, the fog light relay, the fog light switch, the front-ECU or the ETACS-ECU may be defective.

If the trouble above occurs, the front-ECU may be defective.

If one of the fog lights does not illuminate, the fog light relay or the fog light bulb may be defective. If the fog light indicator light does not illuminate, the combination meter may be defective.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 34

The ETACS-ECU operates the dome light according to the following signals

1. Ignition switch (IG1)
2. Key reminder switch
3. Front door switch
4. All door switches
5. Driver's door lock actuator switch

Is the dome light does not flash normally, a burned-out dome light bulb, the input circuits from the switches described in "CIRCUIT OPERATION", the power supply line to the switches or the ETACS-ECU may be defective. Alternatively, the delay-off function may be set to "0 second" by using the adjustment function.

The ETACS-ECU operates the dome light dimming function according to the input signals from the following switches

1. Ignition switch (IG1)
2. Key reminder switch
3. Door switches
4. Driver's door lock actuator switch

Is the dome lights do not dim normally, the input circuits from the switches described in "CIRCUIT OPERATION" or the ETACS-ECU may be defective.

1. When the ETACS-ECU receives a "LOCK" signal from the door lock actuator switch, it illuminates the security indicator light for approximately 18 seconds, and then set the theft-alarm system.
2. The ETACS-ECU sets the theft-alarm system according to the input signals from the following signals: Key reminder switch: ON Driver's and front passenger's door switch: OFF Door switches: OFF Driver's, front passenger's and back door lock key cylinder switch: LOCK Driver's, front passenger's, rear and back door lock actuator switch: LOCK Hood switch: OFF Transmitter switch: LOCK
3. Vehicle condition Ignition key has been removed from the ignition key cylinder. All doors: Closed Driver's, front passenger's and back door lock key cylinder: Not operated Hood: Closed Transmitter: LOCK switch is operated

If the theft-alarm system is set normally, the input signal circuit, the "SECURITY" indicator light or the ETACS-ECU may be defective.

When the theft-alarm system is triggered, the ETACS-ECU sounds the theft-alarm horn and all the vehicle horns.

If the theft-alarm horn and the vehicle horns do not sound when the theft-alarm system is triggered, the ETACS-ECU may be defective.

If the headlights (high beam) illuminate normally, the front-ECU or the ETACS-ECU may be defective.

If the keyless entry system is normal, the ETACS-ECU may be defective.

The ETACS-ECU operates the following equipment according to signal from the ignition switch (ACC)

1. Windshield wiper and washer
2. Rear wiper and washer

If the signal is not normal, the equipment, which is described in "CIRCUIT OPERATION", does not work normally.

1. The ETACS-ECU operates the following equipment or functions according to signal from the ignition switch (IG1): Ignition key reminder tone alarm function Light reminder tone alarm function Seat belt tone alarm function Power window timer function Seat belt warning light Headlight automatic shutdown function Turn-signal light Dome light dimming function
2. If the power supply circuit from the battery to the ETACS-ECU is open, this circuit is used as backup circuit.

If the signal is not normal, the equipment or functions, which are described in "CIRCUIT OPERATION", do not work normally.

The ETACS-ECU operates the fog lights according to signal from the fog light switch.

If the signal is not normal, the fog lights do not work normally. If the signal is not normal, the fog light switch or the ETACS-ECU may be defective.

The ETACS-ECU operates the rear wiper according to signal from the park/neutral position switch.

Note. The park/neutral position switch is shared with the automatic transmission control system. If this problem is not solved, carry out the troubleshooting regarding the automatic transmission control system. See DIAGNOSIS - R4A51, V4A51 & V5A51 article.

If the signal is not normal, the rear wiper does not operate consecutively twice when the selector lever is moved to the "R" position with the rear wiper on. If the signal is not normal, the park/neutral position switch or the ETACS-ECU may be defective.

The ETACS-ECU operates the following functions or systems according to signal from the driver's or front passenger's door switches

1. Ignition key reminder tone alarm function
2. Light reminder tone alarm function
3. Power window timer function
4. Headlight automatic shutdown function
5. Dome light

If the signal is not normal, the functions or systems, which are described in "CIRCUIT OPERATION", do not work normally. If the signal is not normal, the driver's or front passenger's door switch or the ETACS-ECU may be defective.

The ETACS-ECU operates the following equipment or functions according to signal from the column switch (turn-signal light and lighting switch)

1. Light reminder tone alarm function
2. Headlight
3. Turn-signal light

If the signal is not normal, the equipment or functions, which are described in "CIRCUIT OPERATION", do not work normally. If the signal is not normal, the column switch (turn-signal light and lighting switch) or the ETACS-ECU may be defective.

The ETACS-ECU operates the following equipment or functions according to signal from the column switch (windshield wiper and washer switch)

1. Windshield wiper and washer
2. Rear wiper and washer

If the signal is not normal, the equipment, which is described in "CIRCUIT OPERATION", does not work normally.

The ETACS-ECU calculates the windshield intermittent wiper interval according to the position of the windshield intermittent wiper interval adjusting knob, which is incorporated in column switch (windshield wiper and washer switch).

If the windshield intermittent wiper interval can not be adjusted, the column switch or the ETACS-ECU may be defective.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 35

Scheme 36

The ETACS-ECU receives a signal through the sunroof motor assembly via the SWS communication line from the sunroof switch, and sends a signal to the data link connector.

If the SWS communication line between the sunroof motor assembly and the ETACS-ECU is defective, the ETACS-ECU cannot identify the input signal from the sunroof switch even if the sunroof is normal.

Note. This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, see HOW TO USE SWS MONITOR .

Scheme 37

The RV meter sends a tone alarm request signal to the SWS communication line. If the ETACS-ECU receives the request signal, it sound its tone alarm.

If the SWS communication line between the RV meter and the ETACS-ECU is defective, the ETACS-ECU can not identify any input signals from the RV meter even if the RV meter is normal.

The ETACS-ECU operates the following functions or systems according to signal from the key reminder switch

1. Ignition key reminder tone alarm function
2. Keyless entry system
3. Dome light dimming function

If the signal is not normal, the functions or systems, which are described in "CIRCUIT OPERATION", do not work normally.

The ETACS-ECU operates the following functions or systems according to signal from the hazard warning light switch

1. Hazard warning light
2. Keyless entry system (registering the encrypted code)

If the signal is not normal, the equipment or systems, which are described in "CIRCUIT OPERATION", do not work normally.

The ETACS-ECU operates the following functions and equipment according to signal from the driver's seat belt switch

1. Seat belt tone alarm function
2. Seat belt warning light

If the signal is not normal, the equipment and functions, which are described in "CIRCUIT OPERATION", do not work normally.

The ETACS-ECU operates the following functions or systems according to signal from the driver's or front passenger's, rear or back door switches

1. Light reminder tone alarm function < Driver's door switch >
2. Power window timer function < Driver's, front passenger's door switch >
3. Headlight automatic shutdown function < Driver's door switch >
4. Keyless entry system < All door switches >
5. Dome light < All door switches >

If the signal is not normal, the functions or systems, which are described in "CIRCUIT OPERATION", do not work normally. If the signal is not normal, the driver's, front passenger's, rear or back door switch or the ETACS-ECU may be defective.

The ETACS-ECU operates the central door locking system according to signal from the driver's door lock key cylinder switch.

If the signal is not normal, the systems, which are described in "CIRCUIT OPERATION", do not work normally.

The ETACS-ECU operates the following functions or systems according to signal from the driver's or front passenger's, rear or back door lock actuator switch

1. Central door locking system
2. Keyless entry system
3. Dome light dimming function

If the signal is not normal, the functions or systems, which are described in "CIRCUIT OPERATION", do not work normally.

The ETACS-ECU operates the central door locking system according to signal from the door lock switch.

If the signal is not normal, the doors is not locked or unlocked. If the signal is not normal, the power window main switch, power window sub switch or the ETACS-ECU may be defective.

The ETACS-ECU makes the rear wiper stop at the predetermined park position according to the auto-stop signal from the rear wiper motor.

If this signal is not normal, the rear wiper does not stop at the predetermined park position.

The ETACS-ECU operates the theft-alarm system according to signal from the hood switch.

If the signal is not normal, the theft-alarm system does not work normally.

The ETACS-ECU receives signal through its receiver from the transmitter, and operates the keyless entry system according to the signal.

If the signal is not normal, the systems, which are described in "CIRCUIT OPERATION", do not work normally.