Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSLEXUS2009GS 350 RWD V6-3.5L (2GR-FSE)REPAIR AND DIAGNOSISA L L DIAGNOSTIC TROUBLE CODES ( DTC )TESTING AND INSPECTIONP CODE CHARTSP1277
2009 Lexus GS 350 RWD V6-3.5L (2GR-FSE)
P1277
2009 Lexus GS 350 RWD V6-3.5L (2GR-FSE)SECTION P1277
2GR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P1276: Port Injector Circuit No. 1
DTC P1276 - Port Injector Circuit No. 1
DTC P1277 - Port Injector Circuit No. 2
DTC P1278 - Port Injector Circuit No. 3
DTC P1279 - Port Injector Circuit No. 4
DTC P127A - Port Injector Circuit No. 5
DTC P127B - Port Injector Circuit No. 6
DESCRIPTION
The D-4S system has two injection systems. One is the in-cylinder direct injection system that directly injects pressurized fuel into the combustion chamber. The other is the intake port injection system. The ECM determines the percentage of in-cylinder direct injection to the intake port injection systems in accordance with the engine speed and load.
MONITOR DESCRIPTION
The ECM monitors the injection control of the port injector. If a malfunction is detected in the port injector circuit, the ECM cancels the injection control for the corresponding cylinder and turns on the MIL.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
WIRING DIAGRAM
INSPECTION PROCEDURE
PROCEDURE
1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P1276, P1277,P1278,P1279, P127A OR P127B)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Select the following menu items: Powertrain / Engine and ECT / Trouble Codes.
(e) Read DTCs.
Result:
B -- GO TO DTC CHART
A -- Continue to next step.
2. CHECK HARNESS AND CONNECTOR (TERMINAL VOLTAGE)
(a) Disconnect the fuel injector for port injection connector.
(b) Turn the engine switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:
NG -- CHECK AND REPAIR HARNESS OR CONNECTOR (IG2 RELAY - INJECTOR FOR PORT INJECTION)
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (ECM - FUEL INJECTOR FOR PORT INJECTION)
(a) Disconnect the E6 and E8 ECM connectors.
(b) Disconnect the injector for port injection connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for short):
Standard resistance (Check for short):
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
4. CHECK FUEL INJECTOR FOR PORT INJECTION (RESISTANCE)
(a) Check the fuel injector for port injection resistance Fuel Injector (for Port Injection).
NG -- REPLACE FUEL INJECTOR FOR PORT INJECTION
OK -- REPLACE ECM
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.