Based on information from various sensors, the ECM controls the amount of fuel sent to the cylinder via the fuel injection system. The fuel injector is a solenoid-operated valve that meters the fuel. The ECM controls by length of time the fuel injector is held open. The ECM grounds the injector control circuit to open the injector. When the ECM energizes the injector by grounding the control circuit, the circuit voltage should be pulled low (theoretically 0V) and the fuel is injected. When the ECM de-energizes the injector by opening the control circuit, the fuel injector is closed and circuit voltage should momentarily peak before settling back to system voltage.
Checking output signals from injectors. Under detecting condition, if an output signal is high, ECM sets P0277.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Signal High |
•
Poor connection
•
Short to battery in harness
•
Injector
•
ECM |
Enable Conditions |
•
Engine running state
•
11V ≤ Battery voltage ≤ 16V
•
Above conditions are met > 0.5sec. | |
Threshold value |
•
Short to battery | |
Diagnosis Time |
•
Continuous (more than 5 sec. failure for every 10 sec.test) | |
MIL On Condition |
•
3 Driving Cycles |
Item | Coil resistance(Ω) |
Injector | 13.8 ~ 15.2 [20℃(68℉)] |
Fig.1) Normal waveforms of Injector under idle condition.
When the ECM energizes the injector by grounding 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 at a moment.
