DTC P12D5-01: Fuel Pump Control General Electrical Failure [10/2022 - ]: Procedure

Pre-procedure1

• Remove the fuel pump control ECU.

  HINT: 

  Refer to REMOVAL [10/2022 - ]

• Measure the resistance according to the value(s) in the table below.

  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

  *a

  Component without harness connected (Fuel Pump Control ECU)

  -

  -

  Standard Resistance

  Tester Connection	Condition	Specified Condition	Result
  H121-2 (FPU) - H122-3 (GND)	Always	2 kΩ or higher	kΩ
  H121-3 (FPV) - H122-3 (GND)	Always	2 kΩ or higher	kΩ
  H121-4 (FPW) - H122-3 (GND)	Always	2 kΩ or higher	kΩ

  HINT: 

  This procedure checks for an internal short of the fuel pump control ECU when its transistor is stuck on.

  Result

  Proceed to
  OK
  NG

Post-procedure1

• None.

Result: 

NG 

REPLACE FUEL PUMP CONTROL ECU. Refer to  REMOVAL [10/2022 - ] 

Result: 

OK 

See step  2

Pre-procedure1

• Disconnect the H121 fuel pump control ECU connector.

• Operate the fuel pump control ECU using the Active Test function and measure the voltage according to the value(s) in the table below.

  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

  *a	Component without harness connected (Fuel Pump Control ECU)

  Powertrain > Engine > Active Test 

  Tester Display
  Fuel Pump Single Phase Energization

  Standard Voltage

  Tester Connection	GTS Operation	Specified Condition
  H121-2 (FPU) - Body ground	U Phase	4.4 to 8.4 V*
  H121-3 (FPV) - Body ground		8 to 15.5 V
  H121-4 (FPW) - Body ground		8 to 15.5 V
  H121-3 (FPV) - Body ground	V Phase	4.4 to 8.4 V*
  H121-2 (FPU) - Body ground		8 to 15.5 V
  H121-4 (FPW) - Body ground		8 to 15.5 V
  H121-4 (FPW) - Body ground	W Phase	4.4 to 8.4 V*
  H121-2 (FPU) - Body ground		8 to 15.5 V
  H121-3 (FPV) - Body ground		8 to 15.5 V

  HINT: 

  • *: This Active Test limits the fuel pump control ECU output duty cycle to 50%. Therefore, the output voltage of the fuel pump control ECU will be approximately 50% of the power source voltage (+B terminal).
  • Before performing this inspection, check that the battery voltage is between 11 and 14 V (not depleted).

  Result

  Proceed to
  OK
  NG

Post-procedure1

• None.

Result: 

NG 

REPLACE FUEL PUMP CONTROL ECU. Refer to  REMOVAL [10/2022 - ] 

Result: 

OK 

See step  3

Pre-procedure1

• Disconnect the fuel pump control ECU connector.
• Disconnect the fuel pump (for low pressure side) connector.

• Measure the resistance according to the value(s) in the table below.

  Standard Resistance

  Tester Connection	Condition	Specified Condition	Result
  H121-2 (FPU) or H187-3 (BLPU) - Body ground and other terminals	Always	10 kΩ or higher	kΩ
  H121-3 (FPV) or H187-4 (BLPV) - Body ground and other terminals	Always	10 kΩ or higher	kΩ
  H121-4 (FPW) or H187-2 (BLPW) - Body ground and other terminals	Always	10 kΩ or higher	kΩ

  Result

  Proceed to
  OK
  NG

Post-procedure1

• None.

Result: 

OK 

REPLACE FUEL PUMP (FOR LOW PRESSURE SIDE). Refer to  REMOVAL [10/2022 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR