P0261
COMPONENT LOCATION
GENERAL DESCRIPTION
Based on information from various sensors, the ECM measures 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 low, PCM sets P0261. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.
DTC DETECTING CONDITION
SIGNAL WAVEFORM AND DATE
When the PCM energizes the injector by grounding control circuit, the circuit voltage should be low (theoretically 0V) and the fuel is injected. When the PCM de-energizes the injector by opening control circuit, the fuel injector is closed and circuit voltage should be peak at a moment.
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 F4(DTAL) to check DTC's information from the DTCs menu
(4) Read "DTC Status" parameter.
(5) Is parameter displayed "Present fault"?
YES
> Go to "Terminal and connector inspection" procedure.
NO
> Fault is intermittent caused by poor contact in the sensor's and/or PCM's connector or was repaired and PCM 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 terminals. 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 "Power Circuit Inspection" procedure.
POWER CIRCUIT INSPECTION
1. IG "ON" and disconnect injector connector.
2. IG "ON" and ENG "OFF"
3. Measure voltage between terminal 1 of injector harness connector and chassis ground.
Specification : B+
4. Is the measured voltage within specification?
YES
> Go to "Control Circuit Inspection" procedure.
NO
> Check open or connection of the fuse connected to injector power supply.
> Repair open or short to ground in harness, and go to "Verification of Vehicle Repair' procedure.
CONTROL CIRCUIT INSPECTION
1. Check short to ground in harness
(1) IG "OFF" and disconnect injector connector and PCM connector.
(2) Measure resistance between terminal 2 of injector harness connector and chassis ground.
Specification : Infinite
(3) Is the measured resistance within specification?
YES
> Go to "Check open in harness" as follows.
NO
> Repair short to ground in harness, and go to "Verification of Vehicle Repair" procedure.
2. Check open in harness
(1) IG "OFF" and disconnect injector connector and PCM connector.
(2) Measure resistance between terminal 2 of injector harness connector and C201-2 (72) of PCM harness connector.
Specification : Below 1Ohms
(3) Is the measured resistance within specification?
YES
> Go to "Component Inspection" procedure.
NO
> Repair open 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 PCM and check for proper operation. If the problem is corrected, replace PCM 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 PCM. After testing PCM on the vehicle, use this function to reuse the PCM on the others
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code(DTC) which has been diagnosed.
2. Using a Scantool, Clear the DTCs
3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions
4. Monitor that all rediness test have been verified as " Complete "
5. Are any DTCs present ?
YES
> Go to the applicable troubleshoooting procedure.
NO
> System is performing to specification at this time.