Diagnostic trouble code P1235 4GR-FSE Engine

Description

Wiring diagram

Inspection procedure

INSPECT FUEL PUMP FOR HIGH PRESSURE

CHECK HARNESS AND CONNECTOR (INJECTOR DRIVER - HIGH PRESSURE SIDE FUEL PUMP)

INSPECT ECM (FPD AND FPF1 VOLTAGE)

CHECK HARNESS AND CONNECTOR (INJECTOR DRIVER - ECM)

DTC P1235 High Pressure Fuel Pump Circuit

Description

The high pressure side fuel pump is attached to the insulator, which is attached to the cylinder head cover. The pump activates according to the position of the cam on the exhaust side camshaft (right bank). The high pressure side fuel pump increase the pressure of the fuel supplied from the fuel pump in the fuel tank to 4 to 13 MPa (40.8 to 132.6 kgf/cm, 580 to 1,885 psi) according to the operating condition, and it feeds the fuel to the fuel delivery pipe.  

DTC No.	DTC Detection Condition	Trouble Area
P1235	Open or short in high pressure side fuel pump circuit for 1 second or more (1 trip detection logic)	Open or short in high pressure side fuel pump High pressure side fuel pump Injector driver (EDU) ECM

Wiring diagram

Inspection procedure

HINT:

Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred .

 

1.INSPECT FUEL PUMP FOR HIGH PRESSURE

1. Disconnect the E41 fuel pump for high pressure connector.

2. Measure the resistance of the fuel pump for high pressure.

   Standard resistance:

   Tester Connection	Condition	Specified Condition
   1 - 2	20°C (68°F)	1.19 to 1.39 ?

3. Reconnect the fuel pump for high pressure connector.

NG	REPLACE FUEL PUMP FOR HIGH PRESSURE

OK

2.CHECK HARNESS AND CONNECTOR (INJECTOR DRIVER - HIGH PRESSURE SIDE FUEL PUMP)

1. Disconnect the E58 injector driver (EDU) connector.

2. Disconnect the E41 high pressure side fuel pump connector.

3. Measure the resistance of the wire harness side connectors.

   Standard resistance (Check for open):

   Tester Connection	Specified Condition
   FP+ (E58-3) - E41-1	Below 1 ?
   FP- (E58-4) - E41-2	Below 1 ?

   Standard resistance (Check for short):

   Tester Connection	Specified Condition
   FP+ (E58-3) or E41-1 - Body ground	10 k? or higher
   FP- (E58-4) or E41-2 - Body ground	10 k? or higher

4. Reconnect the injector driver (EDU) connector.

5. Reconnect the high pressure side fuel pump connector.

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.INSPECT ECM (FPD AND FPF1 VOLTAGE)

1. Start the engine, and check the waveforms between terminals FPF1 and E1, and FPD and E1 of the E6 and E4 ECM connectors.

HINT:

The correct waveform is as shown in the illustration.

ECM Terminal Name	CH1: FPD (E6-33) - E1 (E4-7) CH2: FPF1 (E6-32) - E1 (E4-7)
Tester Range	2 V/DIV. 5 ms./DIV.
Conditions	Idling with warm engine

OK	REPLACE ECM

NG

4.CHECK HARNESS AND CONNECTOR (INJECTOR DRIVER - ECM)

1. Disconnect the E6 ECM connector.

2. Disconnect the E26 injector driver (EDU) connector.

3. Measure the resistance of the wire harness side connectors.

   Standard resistance (Check for open):

   Tester Connection	Specified Condition
   FPF1 (E6-32) - FPF1 (E26-7)	Below 1 ?
   FPD (E6-33) - FPD (E26-8)	Below 1 ?

   Standard resistance (Check for short):

   Tester Connection	Specified Condition
   FPF1 (E6-32) or FPF1 (E26-7) - Body ground	10 k? or higher
   FPD (E6-33) or FPD (E26-8) - Body ground	10 k? or higher

4. Reconnect the ECM connector.

5. Reconnect the injector driver (EDU) connector.

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
REPLACE INJECTOR DRIVER