Based on information from various sensors, the ECM decides the fuel injection amount. The fuel injector is a solenoid-operated valve and the fuel injection amount is controlled by length of time the fuel injector is held open. The ECM controls each injector by grounding the control circuit. When the ECM energizes the injector by grounding the control circuit, the circuit voltage should be low (theoretically 0V) and the fuel is injected. When the ECM de-energizes the injector by opening control circuit, the fuel injector is closed and circuit voltage should be peak for a moment..
ECM sets DTC P0262,P0265,P0268 or P0271 if the ECM detects each injector control line is open or short short to battery.
Item
Detecting Condition
Possible cause
Monitoring Strategy
? Signal check, High
? Short to battery in control circuit
? Faulty injector’s
? Faulty ECM
Threshold value
? Shorted or disconnected
Enable Conditions
Diagnostic Time
? Continuous
Fail Safe
? None
Check item
Data display
Check conditions
Engine state
Test specification
Injectors
Injector duration
? ECTS : 80 to 95?(176 to 205°F)
? Lamps,electric cooling fan,accessory units : ALL OFF
? Steering wheel : Neutral
Idle rpm
1.5 ~ 4.5 ms
2000 rpm
3000 rpm
Racing
Increasing
Normal Parameter At 20?(68°F)
Resistance
15.9 ± 0.35 ?
This figure shows the voltage waveform on channel1 in idling.
At point ?,the measured voltage should be nearly battery voltage.
The measured voltage at point ? is the surge voltage and is approximately 56V.
The measured voltage at point ? is below 1V and the periode is between 1.8ms and 4ms in idling when warmed up condition.