Gauges & Instrument Panels - Except Evolution: Overview Mitsubishi Lancer IX

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.

Circuit Operation

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 reinforced 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.

Technical Description (Comment)

The cause may be due to malfunction of the output shaft speed sensor circuitry, PCM or speedometer. Vehicle speed sensor is also used by the Powertrain Control Module (PCM), auto-cruise control-ECU.

1. The ignition switch (IG1) circuit is the power source for the speedometer and vehicle speed sensor.
2. The vehicle speed sensor are installed on the transaxle. Four pulses are generated with one turn of the vehicle speed sensor shaft. These pulse signals are sent into the speedometer. The speedometer calculates the pulse signals to operate the needle of the meter. At the same time, the travel distance is calculated.

The cause may be a faulty vehicle speed sensor circuit system or a faulty speedometer. Vehicle speed sensor is also used by the engine control module (ECM) auto-cruise control-ECU.

The tachometer power is supplied from the ignition switch (IG1) circuit. The tachometer calculates the engine revolution (r/min) according to the ECM (M/T) or PCM (A/T) signals to operate the needle.

The cause is thought to be because ECM (M/T) or PCM (A/T) signals are not transmitted or due to combination meter error.

1. The ignition switch (IG1) circuit is the power source for the fuel gauge.
2. The resistance value fluctuates causing the circuit current to fluctuate when the fuel gauge unit float moves up and down.
3. The fuel gauge moves the needle by the circuit current.

The cause is thought to be due to malfunction of the fuel gauge unit or combination meter.

1. The ignition switch (IG1) circuit is the power source for the engine coolant temperature gauge.
2. 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.
3. The engine coolant temperature gauge moves the needle according to the circuit current.

The cause is thought to be due to the 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.