Chassis Electrical: Overview Mitsubishi Eclipse IV

GENERAL DESCRIPTION

The engine immobilizer system prevents the engine from starting and immobilizes the vehicle if a key other than the key registered for that vehicle is used in an attempt to start the engine after forced entry. The engine immobilizer system consists of the ignition key, the key ring antenna, the ETACS-ECU (immobilizer-ECU), and the engine control module (ECM) < M/T > or powertrain control module (PCM) < A/T >. It has these functions

The system is designed to be maintenance-free because the power source for the transponder is supplied by the ETACS-ECU (immobilizer-ECU) via the key ring antenna. Two ignition keys are provided, and up to eight keys can be registered to one vehicle (one receiver) as needed. There are 4 billion combinations for the encrypted code. In addition, one part of the code is changed each time the key is switched on, which improves security by preventing theft using a copied encrypted code.

Scheme 1

OPERATION

With the ignition switch "ON" position, the immobilizer system operates as shown in illustration.

Scheme 2

INTRODUCTION TO IMMOBILIZER SYSTEM DIAGNOSIS

The immobilizer system consists of the ETACS-ECU (immobilizer-ECU), ECM < M/T > or PCM < A/T >, ignition key and ignition key ring antenna. If the engine cannot be started by using a registered ignition key, one of these components may be defective. If the immobilizer system has immobilized the engine, MFI system DTC P0513 will be set. In this case, follow the immobilizer system troubleshooting.

CIRCUIT OPERATION

The ignition key is powered by the ignition key ring antenna. The ignition key then sends an encrypted code. The key reminder switch (ignition key ring antenna) receives the encrypted code, and determines if the ignition key is registered.

TECHNICAL DESCRIPTION (COMMENT)

If a data error is detected in the ECM < M/T > or the PCM < A/T >, diagnosis code No. B1731 will be set.

If the VIN data are not written when the ETACS-ECU is replaced, the ETACS-ECU sets diagnosis code No.B1761.

The ignition key transponder or the ETACS-ECU is suspected to be defective.

TECHNICAL DESCRIPTION

If the engine cranks, but does not start, an MFI system problem may exist in addition to a malfunctioning immobilizer system. The engine will not start if the ignition key has not been properly registered.

The immobilizer indicator starts flashing in approximately 10 seconds after the additional key registration mode is entered. It illuminates for 3 seconds after the additional key registration of the unregistered key is completed or after the registration completion judgment of the registered key. In addition, when a read error is detected, the immobilizer indicator stops flashing after read error judgment.

The immobilizer indicator light or a malfunction of the combination meter or ETACS-ECU.

Some of the combination meter indications are based on information from ECUs via CAN bus communication. If there is any failure in the meters connected via the CAN bus communication, diagnose the CAN bus communication system. The following instruments, indicator lights and warning lights in the combination meter are controlled by ECUs via CAN bus communication.

COMBINATION METER DESCRIPTION

The combination meter receives a signal from the ECM < M/T > or PCM < A/T > and displays the driven distance.

The wiring harness or connectors may have loose, corroded, or damage terminals, or terminals pushed back in the connector, or the combination meter may be defective.

The fuel gauge displays the amount of the remaining fuel on the combination meter.

The wiring harness or connectors may have loose, corroded, or damage terminals, or terminals pushed back in the connector, or the combination meter may be defective.

Some instruments of the combination meter are linked to the CAN bus line. Both the combination meter and the ECM < M/T > or PCM < A/T > have a terminator resistor.

The wiring harness or connectors may have loose, corroded, or damage terminals, or terminals pushed back in the connector, or the combination meter may be defective.

Refer to CIRCUIT OPERATION .

Current trouble

1. Connector(s) or wiring harness in the CAN bus lines between the ECM < M/T > or PCM < A/T > and the combination meter, the power supply system to the ECM < M/T > or PCM < A/T >, the ECM < M/T > or PCM < A/T > itself, or the combination meter may be defective.

Past trouble

1. Carry out diagnosis with particular emphasis on connector(s) or wiring harness in the CAN bus lines between the ECM < M/T > or PCM < A/T > and the combination meter, and the power supply system to the ECM < M/T > or PCM < A/T >. For diagnosis procedures, refer to "How to cope with past trouble" (Refer to How to Use Troubleshooting/Inspection Service Points «HOW TO TREAT PAST TROUBLE»(ref-241284-S30265215842006081100000) ). NOTE: For a past trouble, you may not find it by the MUT-III CAN bus diagnostics even if there is a failure in CAN bus lines. In this case, refer to How to Use Troubleshooting/Inspection Service Points - «HOW TO COPE WITH INTERMITTENT MALFUNCTION»(ref-241284-S30929246612006081100000) .) and check the CAN bus lines. You can narrow down the possible cause of the trouble by referring to the DTC, which is set regarding the CAN communication-linked ECUs (Refer to «EXPLANATION ABOUT THE SCAN TOOL (MUT-III) CAN BUS DIAGNOSTICS»(ref-241285-S15273355012006081100000) ).

Refer to CIRCUIT OPERATION .

Current trouble

1. Connector(s) or wiring harness in the CAN bus lines between the PCM and the combination meter, the power supply system to the PCM, the PCM itself, or the combination meter may be defective.

Past trouble

1. Carry out diagnosis with particular emphasis on connector(s) or wiring harness in the CAN bus lines between the PCM and the combination meter, and the power supply system to the PCM. For diagnosis procedures, refer to "How to cope with past trouble" (Refer to How to Use Troubleshooting/Inspection Service Points «HOW TO TREAT PAST TROUBLE»(ref-241284-S30265215842006081100000) ). NOTE: For a past trouble, you may not find it by the MUT-III CAN bus diagnostics even if there is a failure in CAN bus lines. In this case, refer to How to Use Troubleshooting/Inspection Service Points - «HOW TO COPE WITH INTERMITTENT MALFUNCTION»(ref-241284-S30929246612006081100000) .) and check the CAN bus lines. You can narrow down the possible cause of the trouble by referring to the DTC, which is set regarding the CAN communication-linked ECUs (Refer to «EXPLANATION ABOUT THE SCAN TOOL (MUT-III) CAN BUS DIAGNOSTICS»(ref-241285-S15273355012006081100000) ).

Refer to CIRCUIT OPERATION .

Current trouble

1. Connector(s) or wiring harness in the CAN bus lines between the ABS-ECU and the combination meter, the power supply system to the ABS-ECU, the ABS-ECU itself, or the combination meter may be defective.

Past trouble

1. Carry out diagnosis with particular emphasis on connector(s) or wiring harness in the CAN bus lines between the ABS-ECU and the combination meter, and the power supply system to the ABS-ECU. For diagnosis procedures, refer to "How to cope with past trouble" (Refer to «HOW TO TREAT PAST TROUBLE»(ref-241284-S30265215842006081100000) ). NOTE: For a past trouble, you may not find it by the MUT-III CAN bus diagnostics even if there is a failure in CAN bus lines. In this case, refer to How to Use Troubleshooting/Inspection Service Points - «HOW TO COPE WITH INTERMITTENT MALFUNCTION»(ref-241284-S30929246612006081100000) .) and check the CAN bus lines. You can narrow down the possible cause of the trouble by referring to the DTC, which is set regarding the CAN communication-linked ECUs (Refer to «EXPLANATION ABOUT THE SCAN TOOL (MUT-III) CAN BUS DIAGNOSTICS»(ref-241285-S15273355012006081100000) ).

The ETACS-ECU communicates with the combination meter and the powertrain control module via CAN bus line to obtain necessary information. Both the combination meter and the powertrain control module have terminator resistors.

Current trouble

1. Connector(s) or wiring harness in the CAN bus lines between the ETACS-ECU and the combination meter, the power supply system to the ETACS-ECU, the ETACS-ECU itself, or the combination meter may be defective.

Past trouble

1. Carry out diagnosis with particular emphasis on connector(s) or wiring harness in the CAN bus lines between the ETACS-ECU and the combination meter, and the power supply system to the ETACS-ECU. For diagnosis procedures, refer to "How to cope with past trouble" (Refer to «HOW TO TREAT PAST TROUBLE»(ref-241284-S30265215842006081100000) ). NOTE: For a past trouble, you may not find it by the MUT-III CAN bus diagnostics even if there is a failure in CAN bus lines. In this case, refer to How to Use Troubleshooting/Inspection Service Points - «HOW TO COPE WITH INTERMITTENT MALFUNCTION»(ref-241284-S30929246612006081100000) .) and check the CAN bus lines. You can narrow down the possible cause of the trouble by referring to the DTC, which is set regarding the CAN communication-linked ECUs (Refer to «EXPLANATION ABOUT THE SCAN TOOL (MUT-III) CAN BUS DIAGNOSTICS»(ref-241285-S15273355012006081100000) ).

Refer to CIRCUIT OPERATION .

Current trouble

1. Connector(s) or wiring harness in the CAN bus lines between the SRS-ECU and the combination meter, the power supply system to the SRS-ECU, the SRS-ECU itself, or the combination meter may be defective.

Past trouble

1. Carry out diagnosis with particular emphasis on connector(s) or wiring harness in the CAN bus lines between the SRS-ECU and the combination meter, and the power supply system to the SRS-ECU. For diagnosis procedures, refer to "How to cope with past trouble" (Refer to «HOW TO TREAT PAST TROUBLE»(ref-241284-S30265215842006081100000) ). NOTE: For a past trouble, you may not find it by the MUT-III CAN bus diagnostics even if there is a failure in CAN bus lines. In this case, refer to How to Use Troubleshooting/Inspection Service Points - «HOW TO COPE WITH INTERMITTENT MALFUNCTION»(ref-241284-S30929246612006081100000) .) and check the CAN bus lines. You can narrow down the possible cause of the trouble by referring to the DTC, which is set regarding the CAN communication-linked ECUs (Refer to «EXPLANATION ABOUT THE SCAN TOOL (MUT-III) CAN BUS DIAGNOSTICS»(ref-241285-S15273355012006081100000) ).

Refer to CIRCUIT OPERATION .

Current trouble

1. The ECM < M/T > or PCM < A/T > or the combination meter may be defective.

Past trouble

1. Carry out diagnosis with particular emphasis on connector(s) or wiring harness between the ECM < M/T > or PCM < A/T > and the combination meter. For diagnosis procedures, refer to "How to cope with past trouble" (Refer to «HOW TO TREAT PAST TROUBLE»(ref-241284-S30265215842006081100000) ).

Refer to CIRCUIT OPERATION .

The combination meter is linked to the data link connector via CAN bus line to communicate with the scan tool.

If the system does not communicate with scan tool, power supply to data link connector or CAN bus lines may be defective.

The combination meter is energized by the battery through ignition switch (IG1).

If the odometer and trip meter are not displayed or all meter needles don't move, power supply and ground system to the combination meter, or the combination meter itself may be defective.

The output shaft speed sensor sends vehicle signal to the combination meter via the ECM < M/T > or PCM < A/T > and the CAN bus line.

If only the speedometer does not operate, the ECM < M/T > or PCM < A/T > system, the combination meter, the wiring harness or its connector may be defective. Furthermore, incorrect level of fuel is shown on the gauge, because the display unit can not learn the fuel gauge.

The ECM < M/T > or PCM < A/T > sends ignition signal to the combination meter via CAN bus line.

If only the tachometer does not operate, the ECM < M/T > or PCM < A/T > system may not be sending ignition signal, or the combination meter, the wiring harness or its connector may be defective.

1. The ignition switch (IG1) circuit is the power supply for the fuel gauge.
2. When the float in the fuel level sensor moves, the circuit resistance will change.
3. The fuel gauge needle is moved by a change in the circuit current.

If only the fuel gauge does not operate, the fuel pump module, the fuel level sensor (sub), the combination meter, wiring harness or connector(s) may be defective.

The engine coolant temperature sensor sends signal to the combination meter via the ECM < M/T > or PCM < A/T > and the CAN bus line.

If only the engine coolant temperature gauge does not operate, the ECM < M/T > or PCM < A/T > system, the combination meter, the wiring harness or its connector may be defective.

The fuel warning light illuminates when the fuel gauge of the combination meter indicates a predetermined value or lower.

If only the fuel warning light does not operate, the fuel pump module, the fuel level sensor (sub), the combination meter, wiring harness or connector(s) may be defective.

INTRODUCTION TO AUDIO SYSTEM DIAGNOSIS

The diagnosis for symptoms such as noise being emitted, no sound being played, or sound coming only out of one speaker (or set of speakers) is provided.

Power is supplied to the radio and CD player or radio and CD player with CD changer when the ignition switch is in the "ACC" position or "ON" position.

When the ignition is switched on, the radio and CD player or radio and CD player with CD changer will return to the previous state when the ignition was switched off at the last time.

The cause is probably a faulty radio and CD player or radio and CD player with CD changer power supply circuit.

If the remote controlled radio switch is operated, the output voltage will change. The radio and CD player with CD changer operates according to the change on the voltage. You can control the mode and volume by the remote controlled radio switch (RH). You can select a CD track and pre-set radio station, and tune it by the remote controlled radio switch (LH).

If the system does not recognize the remote controlled radio switches (RH), the clock spring or the radio and CD player with CD changer may be defective.

Refer to INSPECTION PROCEDURE 2 .

Refer to INSPECTION PROCEDURE 2 .

Refer to INSPECTION PROCEDURE 2 .

Refer to INSPECTION PROCEDURE 2 .

Power is supplied from the battery directly to the audio amplifier.

The cause is probably a faulty audio amplifier power supply circuit system.

The speakers sound according to audio signal output from the radio and CD player.

The cause is probably a faulty speaker circuit system.

The sound signals are sent from the audio amplifier. After the signals are amplified and filtered, the sound signals are sent to the speaker.

The cause is probably a faulty speaker circuit system.

The sound signals are sent from the radio and CD player with CD changer. After the signals are amplified and filtered, the sound signals are sent to the speaker.

The cause is probably a faulty speaker circuit system.

Power is continuously supplied to the radio and CD player or radio and CD player with CD changer.

The cause is probably a faulty radio and CD player or radio and CD player with CD changer memory backup power supply system circuit.

DEFOGGER OPERATION

The defogger relay turns ON if the defogger switch built-in the A/C-ECU is turned ON when the ignition switch is in the "ON" position. When the defogger relay turns ON, power is supplied to the defogger and the defogger is activated. The defogger comes with a timer function that causes the defogger switch to automatically turn OFF about 17 minutes after the defogger switch is turned ON.

The multi-center display comes in two types.

1. Clock display (incorporating clock) < TYPE1, TYPE2 >
2. Compass display (incorporating compass sensor) < TYPE1 >
3. Ambient air temperature display (communicating with the ambient temperature sensor) < TYPE1 >
4. Audio system operation display (communicating with radio and CD player via M bus) < TYPE1, TYPE2 >

The multi-center display unit is energized by the battery through the ignition switch (ACC) and (IG1).

The ground circuit, the battery circuit, the ignition switch (ACC) circuit or the ignition switch (IG1) circuit is suspected to be open or defective.

The ambient air temperature sensor signal sent to multi-center display unit.

The ambient air temperature sensor circuit is suspected to be open or short.

The ambient air temperature display in the multi-center display unit is controlled by input signals from the ambient air temperature sensor and vehicle speed signals from the ECM < M/T > or PCM < A/T >.

1. If the vehicle speed does not exceed 20 km/h (12.4 mph) for 30 seconds or more, the rise in the ambient air temperature is not displayed.
2. The ambient temperature sensor circuit is suspected to be open or short.

The multi-center display unit receives information from the radio and CD player with CD changer < Vehicles with audio amplifier > or radio and CD player < Vehicles without audio amplifier > via M-bus communication to display the audio system operation condition.

The audio system operation screen will be frozen if the multi-center display have received abnormal data from the radio and CD player with CD changer < Vehicles with audio amplifier > or radio and CD player < Vehicles without audio amplifier > via M-bus communication within 30 seconds. If the abnormal data is received further 30 seconds from that point, a message "E" will be displayed.

The compass sensor, which measures the direction of the vehicle, is incorporated in the multi-center display unit. If the direction of the vehicle is not displayed normally by repeating the manual calibration, the compass sensor may be defective, the vehicle body may have been magnetized, or the manual calibration is performed in strongly magnetized environment.