Mazda 323 C DOHC Engine Workshop Manual

Online Pdf Mazda 323 C DOHC Engine Workshop Manual

air temperature sensor
Function
The air temperature sensor is a temperature-sensitive resistor. Low temperature causes high resistance while high temperature causes low resistance. The control unit determines the temperature by monitoring the voltage across the sensor.

Specifications
supply voltage: 5 V (connector disconnected) resistance: 2,000 - 3,000 ohms / 20°C resistance: 200 - 300 ohms / 90°C

he evaporative canister is equipped with a purge solenoid valve. The control unit switches the solenoid on or off. This controls the amount of vapour purged into the inlet manifold.

Specifications
supply voltage: 12 V resistance: 25 - 35 ohms

Diagnosis
Check connector(s): Inspect the connector(s) and if necessary clean or fix them to make sure the connection is good. Check resistance: 
Turn ignition off. Remove connector from solenoid. 
Measure resistance between the two pins of the solenoid. Compare with specified resistance. Alternatively, check solenoid function by applying battery voltage to its pins. The solenoid should "click". 

Check supply voltage: 
Turn ignition off. Remove connector from solenoid. 
Start the engine and measure voltage between one connector terminal and the negative terminal of the battery. Check the second terminal. One of the two should equal battery voltage. If not check wiring and, if present, fuse(s) and relay.

Check connection to ECU: 
Turn ignition off. Remove connector from solenoid and ECU. 
Measure the resistance between one of the two connector terminals and the corresponding terminal in the ECU connector. Check the other terminal. One of the two should be < 1 ohm. If not check wiring.

The evaporative gases produced in the fuel tank are absorbed by the activated charcoal in the carbon canister. As The purge control solenoid valve opens these gases are delivered to the intake manifold for combustion purposes. The purge control solenoid valve is controlled by the control unit. The control unit operates this valve during the time the lambda control loop is active.

Electrical control
Most solenoids are normally closed. This means that the connection between the canister and the intake manifold is closed. The solenoid has a connector with two terminals. On one of those terminals is connected to the battery voltage. This supply-voltage is often switched with a relay. The other terminal leads directly to the control unit. The current through the solenoid is switched on during the time the control unit connects this terminal to ground. The voltage on this terminal is during this time 0 Volts. During the time the solenoid is switched off, the voltage on this terminal is 12 Volts. Some motormanagement systems control the amount gases delivered to the intake manifold switching the solenoid on and of with a certain duty cycle. In this case the duty-cycle depends on engine RPM and engine load.

Online Pdf Mazda 323 C DOHC Engine Workshop Manual