P0277

COMPONENT LOCATION





GENERAL DESCRIPTION

Based on information from various sensors, the ECM calculates 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 the control circuit, the fuel injector is closed and circuit voltage should momentarily peak.

DTC DESCRIPTION

Checking output signals from injectors under detecting condition, if an output signal is high, ECM sets P0277. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.

DTC DETECTING CONDITION





SIGNAL WAVEFORM AND DATA




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 momentarily peak.

SPECIFICATION





SCHEMATIC DIAGRAM





MONITOR DTC STATUS

1. Check DTC Status
(1) Connect scantool to Data Link Connector(DLC).
(2) IG "ON".
(3) Select "Diagnostic Trouble Codes(DTCs)" mode, and then Press F5(INFO) to check DTC's information from the DTCs menu.
(4) Read "DTC Status" parameter.




(5) Is "Present" Fault displayed?
YES
> Go to "Terminal and connector inspection" procedure.
NO
> Fault is intermittent caused by poor contact in the sensor's and/or ECM's connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.

TERMINAL AND CONNECTOR INSPECTION

1. Many malfunctions in the electrical system are caused by poor harness and terminal condition. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
YES
> Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO
> Go to "Control Circuit Inspection" procedure.

CONTROL CIRCUIT INSPECTION

1. Check voltage
(1) IG "OFF" and disconnect injector connector.
(2) IG "ON" and ENG "OFF"
(3) Measure voltage between terminal 1 of injector harness connector and chassis ground.

Specification : Approx. 0V





(4) Is the measured voltage within specification?
YES
> Go to "Component Inspection" procedure.
NO
> Go to "Check short to battery in harness" as follows.
2. Check short to battery in harness
(1) IG "OFF" and disconnect injector connector and ECM connector.
(2) Measure resistance between terminals 1 and 2 of injector harness connector.

Specification : Below 1Ohms





(3) Is the measured resistance within specification?
YES
> Go to "Component Inspection" procedure.
NO
> Repair short to battery in harness, and go to "Verification of Vehicle Repair" procedure.

COMPONENT INSPECTION

1. Check injector
(1) IG "OFF" and disconnect injector connector.
(2) Measure resistance between terminals 1 and 2 of injector connector.(Component side)
Specification :









(3) Is the measured resistance within specification?
YES
> Substitute with a known - good ECM and check for proper operation. If the problem is corrected, replace ECM and go to "Verification of Vehicle Repair" procedure.
NO
> Substitute with a known - good injector and check for proper operation. If the problem is corrected, replace injector and go to "Verification of Vehicle Repair" procedure.

NOTE:
There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by ECM. After testing ECM on the vehicle, use this function before reusing the ECM

VERIFICATION OF VEHICLE REPAIR

After a repair, it is essential to verify that the fault has been corrected.
1. Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode
2. Press F5(INFO) and confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions
3. Read "DTC Status" parameter
4. Is "History (Not Present)" fault displayed?
YES
> System performing to specification at this time. Clear the DTC
NO
> Go to the applicable troubleshooting procedure.