INTRODUCTION TO IMMOBILIZER SYSTEM DIAGNOSIS
| CAUTION | The encrypted code should always be re-registered when replacing the immobilizer-ECU. If the immobilizer-ECU has been replaced with a new part, the password (vehicle secret code) which has been stored in the immobilizer-ECU for each vehicle will be replaced by a new password (secret code) specified by the customer. |
The immobilizer system consists of the 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. In addition, if the immobilizer system has immobilized the engine, MFI system DTC P0513 will be output. In this case, observe the immobilizer system troubleshooting. Then, if a malfunction is resolved, the MFI system DTC P0513 should not reset.
CIRCUIT OPERATION
The ignition key is powered by the ignition key ring antenna, and sends an encrypted code. The ignition key ring antenna receives the encrypted code, and determines whether the ignition key is a registered key or not.
The Immobilizer-ECU is energized by the MFI relay when the ignition switch is turned "ON". The ECM < M/T > or PCM < A/T > transmits a signal from scan tool MB991958 to the immobilizer-ECU as it is. In the same way, a signal from the immobilizer-ECU is also transmitted to scan tool MB991958 as it is.
TECHNICAL DESCRIPTION (COMMENT)
- This malfunction may be caused by a defective immobilizer-ECU, ECM < M/T > or PCM < A/T >, or a defect in the communication line between the immobilizer-ECU and ECM < M/T > or PCM < A/T >. If this malfunction appears when the MFI system and scan tool MB991958 can communicate each other, MFI system DTC P0513 will reset.
- If the MFI system is normal, the MFI relay can be determined as normal. In addition, if the MFI system and scan tool MB991958 can communicate each other, the circuits between the data link connector and the ECM < M/T > or PCM < A/T > can determined as normal.
Note. If this malfunction appears, MFI system DTC P0513 will be output.
The ignition key transponder or the immobilizer-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.
If the requirements for starting the engine are not satisfied, the immobilizer-ECU flashes the immobilizer indicator for 30 seconds.
The immobilizer indicator light or a malfunction of the combination meter or immobilizer-ECU.
POINTS TO NOTE DURING OPERATION
If none of the functions can be used, check the diagnostic trouble codes, and after carrying out any necessary repairs, repeat the operation.
If an incorrect password is input five times in a row, the immobilizer-ECU judges that an unauthorized operation is being attempted. Start-prevention mode will be set, and engine operation will stop and all special functions will be disabled. If the ignition switch is turned to "ON" position and left in that position for approximately 20 minutes, "Unauthorized operation, start-prevention mode" will be cancelled.
INTRODUCTION TO COMBINATION METER DIAGNOSIS
All vehicles are equipped with an electrical speedometer and tachometer. If the speedometer or tachometer does not function, there may be trouble in the electrical system.
- The ignition switch (IG1) circuit is the power source for the speedometer and output shaft speed sensor.
- The output shaft speed sensor is incorporated in the transaxle. The signals from the output shaft speed sensor are referenced for PCM to send a vehicle speed signal to the speedometer. The speedometer calculates the vehicle speed signal to operate the needle of the meter. At the same time, the travel distance is calculated.
The cause may be due to malfunction of the output shaft speed sensor circuitry, PCM or speedometer. The output shaft speed sensor is also used by the powertrain control module (PCM), auto-cruise control-ECU.
- The ignition switch (IG1) circuit is the power source for the speedometer and vehicle speed sensor.
- The vehicle speed sensor is incorporated in the transaxle. The signals from the vehicle speed sensor are referenced for ECM to send a vehicle speed signal to the speedometer. The speedometer calculates the vehicle speed signal to operate the needle of the meter. At the same time, the travel distance is calculated.
The cause may be due to malfunction of the vehicle speed sensor circuitry, ECM or speedometer. The vehicle speed sensor is also used by the engine control module (ECM).
- The tachometer power is supplied from the ignition switch (IG) circuit.
- The tachometer calculates the engine revolution (r/min) according to the PCM < A/T > or the ECM < M/T > signals to operate the needle.
The cause is thought to be because PCM < A/T > or ECM < M/T > signals are not transmitted or due to combination meter error.
- The ignition switch (IG1) circuit is the power source for the fuel gauge.
- The resistance value fluctuates causing the circuit current to fluctuate when the fuel level sensor the float moves up and down.
- The fuel gauge moves the needle by the circuit current.
The cause is thought to be due to malfunction of the fuel level sensor, fuel pump and gauge unit or combination meter.
- The ignition switch (IG1) circuit is the power source for the engine coolant temperature gauge.
- Resistance value, which the engine coolant temperature gauge unit sends to the combination meter, is dependent on temperature of the engine coolant. This causes circuit current to fluctuate.
- The engine coolant temperature gauge moves the needle according to the circuit current.
The cause is thought to be due to malfunction of engine coolant temperature gauge unit or the combination meter.
The combination meter is powered by the ignition switch (IG1) and battery.
The cause is thought to be malfunction of the power, ground circuitry or combination meter.
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 side while listening to the audio system or tape is provided.
Power is supplied to the radio and CD player when the ignition switch is in the "ACC" position or "ON" position. When the previous ignition switch is in the "OFF" position by battery power, the "ON" or "OFF" state of the radio and CD player is saved.
The cause is probably a faulty radio and CD player power supply circuit system.
Power is supplied to the amplifier when the battery.
The cause is probably a faulty amplifier power supply circuit system.
The sound is heard from the door speaker and tweeter according to audio signal output from the radio and CD player.
The cause is probably a faulty door speaker and tweeter circuit system.
- The sound signals are sent from the radio and CD player into the amplifier. After the signals are amplified and filtered, the sound signals are sent to the door speaker.
The cause is probably a faulty door speaker circuit system.
The power is constantly supplied to the radio and CD player.
The cause is probably a faulty radio and CD player memory backup power supply circuit system.
GENERAL DESCRIPTION
OPERATION
Rear 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 in about 11 minutes after the defogger switch is turned ON.