Lexus IS250 · Service Manual ENGINE

P1235

Diagnostic trouble codes

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)
  1. Open or short in high pressure side fuel pump
  2. High pressure side fuel pump
  3. Injector driver (EDU)
  4. ECM

WIRING DIAGRAM

A122747E02

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 (Click here).


1. INSPECT FUEL PUMP FOR HIGH PRESSURE

  1. A081503E10
    Disconnect the E41 fuel pump for high pressure connector.

  1. 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 Ω

  1. 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. A107729E05
    Disconnect the E58 injector driver (EDU) connector.

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

  1. 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 Ω
    FP- (E58-4) - E41-2
    		 Below 1 Ω

    Standard resistance (Check for short):
    Tester Connection
    		 Specified Condition
    FP+ (E58-3) or E41-1 - Body ground
    		 10 kΩ or higher
    FP- (E58-4) or E41-2 - Body ground
    		 10 kΩ or higher

  1. Reconnect the injector driver (EDU) connector.

  1. Reconnect the high pressure side fuel pump connector.



 NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3. INSPECT ECM (FPD AND FPF1 VOLTAGE)

  1. A107730E04
    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. A107731E06
    Disconnect the E6 ECM connector.

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

  1. 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 Ω
    FPD (E6-33) - FPD (E26-8)
    		Below 1 Ω

    Standard resistance (Check for short):
    Tester Connection
    		 Specified Condition
    FPF1 (E6-32) or FPF1 (E26-7) - Body ground
    		 10 kΩ or higher
    FPD (E6-33) or FPD (E26-8) - Body ground
    		 10 kΩ or higher

  1. Reconnect the ECM connector.

  1. Reconnect the injector driver (EDU) connector.



 NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE INJECTOR DRIVER


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