P0270
DTC P0270 CYLINDER 4-INJECTOR CIRCUIT LOWComponent Location:
GENERAL DESCRIPTION
Based on information from various sensors, the PCM 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 PCM controls each injector by grounding the control circuit. When the PCM energizes the injector by grounding the control circuit, the circuit voltage should be low (theoretically 0 V) 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 for a moment.
DTC DESCRIPTION
PCM sets DTC P0261 ,P0264, P0267 or P0270 if the PCM detects each injector control line is short to ground.
Specification:
DTC Detecting Condition:
Schematic Diagram:
SCHEMATIC DIAGRAM
SIGNAL WAVEFORM & DATA
This figure shows the voltage wave form on channel 1 in idling.
1. At point (1),the measured voltage should be nearly battery voltage.
2. The measured voltage at point (2) is the surge voltage and is approximately 56 V.
3. The measured voltage at point (3) is below 1 V and the period is between 1.8 ms and 4 ms in idling when warmed up condition.
When the PCM energizes the injector by grounding the control circuit, the circuit voltage should below (theoretically 0 V) 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 for a moment.
MONITOR DTC STATUS
This is the inspection procedure to determine whether it is present DTC or memoried one by monitoring the current signal or by using the function of oscilloscope with Hi-scan pro.
1. Connect scantool to Data Link Connector(DLC).
2. Warm up the engine to normal operating temperature.
3. Monitor the "INJ duration" parameter on the scantool.
NOTE: The Injector operating time should be checked in P or N range, warmed-up and idling condition.
The data shown above is only for reference and there may be a little difference actually.
4. Service standard
In idling: 2.2 - 5.0 ms
2500 rpm: 2.0 - 5.0 ms
5. Is parameter displayed within specifications?
YES: 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, bending, corrosion,contamination,deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
NO: Go to "W/Harness Inspection" procedure.
TERMINAL & 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. Ignition "OFF"
2. Disconnect INJ connector.
3. Ignition "ON" & Engine "OFF"
4. Measure voltage between terminal 1 of sensor harness connector and chassis ground.
Specification : approximately B+
5. Is measure voltage within Specification?
YES: Go to "Control circuit inspection" procedure.
NO:
- Open circuit or short circuit to chassis ground between INJ harness connector and control relay.
- Repair as necessary and go to "Verification Vehicle Repair" procedure.
NOTE: In case the voltage between terminal 1 of injector and terminal 27, 6, 7 and 47 of PCM is 1 V respectively.
- Suspect area: Open or short circuit of power line from injector to PCM.
CONTROL CIRCUIT INSPECTION
1. Check for open in harness
1. Ignition "OFF"
2. Connect INJ connector and PCM connector.
3. Ignition "ON" & Engine "OFF"
4. Measure voltage between terminal 27 of ECM harness connector and chassis ground.
Specification: approximately B+
5. Is measure voltage within Specification?
YES: Go to "Check for short to ground in harness" as below.
NO:
- Open or Short circuit to chassis ground between INJ harness connector and PCM harness connector.
- Repair as necessary and go to "Verification Vehicle Repair" procedure.
2. Check for short to ground in harness
1. Ignition "OFF"
2. Disconnect INJ connector and PCM connector.
3. Ignition "ON" & Engine "OFF"
4. Measure resistance between terminal 2 of sensor harness connector and chassis ground.
Specification: infinite
5. Is measure resistance within Specification?
YES: Go to "Component Inspection" procedure.
NO:
- Short circuit between injector control circuit and chassis ground.
- Repair as necessary and go to "Verification Vehicle Repair" procedure.
COMPONENT INSPECTION
The purpose of measuring INJ resistance is to find if the open circuit is in the component.
1. Check INJ
1. Measure resistance between terminal 1 and 2 of sensor connector(To sensor side)
Specification: 20 °C(68 °F) :13.8 - 15.2 Ohms
2. Is measure resistance within Specification?
YES: Substitute with a known-good PCM and check for proper operation. If the problem is corrected, replace PCM and then go to "Verification of Vehicle Repair" procedure.
NO: Substitute with a known-good INJ and check for proper operation. If the problem is corrected, replace INJ and then go to "Verification of Vehicle Repair" procedure.
NOTE: The purpose of measuring injector resistance is to find if the open circuit is in the component. So,check the continuity between signal line and ground line.
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 troubleshooting procedure.
NO: System is performing to specification at this time.