Dtc P1526 Fuel Route Switching Valve Relay Stuck On

Engine. Lexus Is250, Is220D. Gse20 Ale20
2Ad-Fhv Engine Control System. Lexus Is250, Is220D. Gse20 Ale20

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

PERFORM ACTIVE TEST BY INTELLIGENT TESTER (OPERATE FUEL PCV RELAY)

INSPECT TERMINAL VOLTAGE (FUEL PCV RELAY TERMINAL)

INSPECT FUEL PCV RELAY

INSPECT FUEL ROUTE SWITCHING VALVE

CHECK HARNESS AND CONNECTOR (ECM - FUEL PCV RELAY)

DTC P1526 Fuel Route Switching Valve Relay Stuck ON

DTC P1527 Fuel Route Switching Valve Relay Stuck OFF


DESCRIPTION

The fuel route switching valve changes the route of fuel discharged from the fuel pump to switch between the fuel transfer operation and priming operation.

DTC No.
DTC Detection Condition
Trouble Area
P1526
When the FUEL PCV relay is ON, the monitor signal is HIGH for 3 seconds.
  1. Short in fuel route switching valve circuit
  2. FUEL PCV relay
  3. ECM
P1527
When the FUEL PCV relay is OFF, the monitor signal is LOW for 3 seconds.
  1. Open or short in fuel route switching valve circuit
  2. FUEL PCV relay
  3. ECM

WIRING DIAGRAM


Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System. Dtc P1526 Fuel Route Switching Valve Relay Stuck On


INSPECTION PROCEDURE

1.PERFORM ACTIVE TEST BY INTELLIGENT TESTER (OPERATE FUEL PCV RELAY)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch ON (IG) and turn the intelligent tester ON.

  1. Enter the following menus: Powertrain / Engine / Active Test / Activate the Fuel Route Switching Valve Relay.

  1. Read the value of Fuel Route Switching Valve while operating it using the intelligent tester.

    Result:

    Fuel Route Switching Valve Relay
    		Fuel Route Switching Valve
    		Proceed to
    ON
    		ON
    		A
    OFF
    		OFF
    		A
    ON
    		OFF
    		B
    OFF
    		ON
    		C


A
CHECK FOR INTERMITTENT PROBLEMS

C
Go to step 4
B


2.INSPECT TERMINAL VOLTAGE (FUEL PCV RELAY TERMINAL)


    Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System. Dtc P1526 Fuel Route Switching Valve Relay Stuck On

  1. Remove the FUEL PCV relay from the engine room J/B and R/B No. 2.

  1. Turn the engine switch ON (IG).

  1. Measure the voltage.

    Standard voltage:
    Tester Connection
    		Specified Condition
    FUEL PCV relay (1) - Body ground
    		9 to 14 V
    FUEL PCV relay (5) - Body ground
    		9 to 14 V


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI MAIN RELAY - FUEL PCV RELAY)
OK


3.INSPECT FUEL PCV RELAY


    Lexus Is250, Is220D. Gse20 Ale20

  1. Remove the FUEL PCV relay from the engine room J/B and R/B No. 2.

  1. Measure the resistance of the relay.

    Standard resistance:
    Tester Connection
    		Specified Condition
    3 - 5
    		10 kΩ or higher
    3 - 5
    		Below 1 Ω
    (when battery voltage applied to terminals 1 and 2)


NG
REPLACE FUEL PCV RELAY
OK


4.INSPECT FUEL ROUTE SWITCHING VALVE


    Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System. Dtc P1526 Fuel Route Switching Valve Relay Stuck On

  1. Inspect fuel route switching valve resistance.

    1. Measure the resistance between terminals 1 and 2.

      Standard resistance:
      0.2 to 3.0 Ω at 20°C (68°F)


NG
REPLACE FUEL ROUTE SWITCHING VALVE
OK


5.CHECK HARNESS AND CONNECTOR (ECM - FUEL PCV RELAY)


    Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System. Dtc P1526 Fuel Route Switching Valve Relay Stuck On

  1. Check the harness and the connectors between the ECM and the FUEL PCV relay.

    1. Disconnect E59 ECM connector.

    2. Remove the FUEL PCV relay from the engine room J/B and R/N No. 2.

    3. Disconnect the fuel route switching valve connector.

    4. Measure the resistance or voltage of the wire harness side connectors.

      Standard resistance (Check for open):
      Tester Connection
      		Specified Condition
      FUEL PCV relay (3) - MPRM (A49-18)
      		Below 1 Ω
      FUEL PCV relay (2) - PPRM (E59-107)
      		Below 1 Ω
      FUEL PCV relay (3) - Fuel route switching valve (1)
      		Below 1 Ω
      Standard resistance (Check for short to ground):
      Tester Connection
      		Specified Condition
      FUEL PCV relay (3), MPRM (A49-18) or Fuel route switching valve (1) - Body ground
      		10 kΩ or higher
      FUEL PCV relay (2) or PPRM (E59-107) - Body ground
      		10 kΩ or higher
      Standard voltage (Check for short to +B):
      Tester Connection
      		Specified Condition
      FUEL PCV relay (3), MPRM (A49-18) or Fuel route switching valve (1) - Body ground
      		Below 1 V
      FUEL PCV relay (2) or PPRM (E59-107) - Body ground
      		Below 1 V


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM