Engine Controls - Basic Diagnostic Procedures - V6 & V8: Overview Toyota Tundra I

FUEL PUMP OPERATION

Note. Electric fuel pump is located in the fuel tank. On all models except Sequoia and Tundra, electric fuel pump operation may be checked by using Toyota hand-held tester or by applying battery voltage to electric fuel pump with electric fuel pump installed in the fuel tank. On Sequoia and Tundra, electric fuel pump operation may be checked by using Toyota hand-held tester. Manufacturer also lists procedure to check fuel pump operation with fuel pump removed from fuel tank and fuel pump mounting bracket.

Scheme 1

Scheme 2

Scheme 3

Scheme 4

Scheme 5

Scheme 6

Scheme 7

Scheme 8

Scheme 9

Scheme 10

1. Connect hand-held tester data link connector No. 3. (Scheme 1)- (Scheme 10). Turn ignition on. DO NOT start engine.
2. Turn hand-held tester on. Select ACTIVE TEST MODE on hand-held tester. Using hand-held tester manufacturer's instructions, activate fuel pump. Listen for fuel pump operating sound and feel for fuel pressure in fuel inlet line near fuel filter or fuel pipe. Turn ignition off. Remove hand-held tester. If fuel pump operates, check fuel pressure. See «FUEL PRESSURE»(ref-11450-S42112471792000111300000).
3. If fuel pump does not operate, EFI main relay or circuit opening relay may be defective. For relay application and explanation of relay operation, see «FUEL PUMP CONTROL CIRCUIT»(ref-11450-S27999258892000111300000). For testing of EFI main relay or circuit opening relay, see appropriate relay under MODULES, MOTORS, RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING - V6 & V8 article.
4. If relays are okay, check for defective fuses, fusible links or wiring. See WIRING DIAGRAMS article. If fuses, fusible links and wiring are okay, check for defective fuel pump. See appropriate «CHECKING FUEL PUMP OPERATION BY APPLYING BATTERY VOLTAGE TO FUEL PUMP»(ref-11450-S18959551612000111300000). If fuel pump operates properly, Engine Control Module (ECM) may be defective. NOTE: For additional testing information for fuel pump control circuit, see FUEL PUMP CONTROL CIRCUIT under COMPUTERIZED ENGINE CONTROLS in SYSTEM & COMPONENT TESTING - V6 & V8 article.

Checking Fuel Pump Operation Using Toyota Hand-Held Tester (Land Cruiser)

1. Connect hand-held tester to data link connector No. 3. (Scheme 5) Turn ignition on. DO NOT start engine.
2. Turn hand-held tester on. Select ACTIVE TEST MODE on hand-held tester. Using hand-held tester manufacturer's instructions, activate fuel pump. Remove intake manifold cover located on top of engine, above intake manifold. Intake manifold cover must be removed for access to fuel pressure pulsation damper located at firewall end of driver's side fuel rail. (Scheme 11) Fuel pressure pulsation damper may also be referred to as pulsation damper.
3. Listen for operating sound at in-tank fuel pump and check that screw at center of fuel pressure pulsation damper moves upward due to the fuel pressure. (Scheme 11) If fuel pump operates, check fuel pressure. See «FUEL PRESSURE»(ref-11450-S42112471792000111300000).
4. If fuel pump does not operate, EFI main relay, fuel pump Electronic Control Unit (ECU) or fuel pump switch may be defective, or fuel pump switch may need to be reset. For explanation of EFI main relay, fuel pump ECU and fuel pump switch operation, or resetting of fuel pump switch, see «FUEL PUMP CONTROL CIRCUIT»(ref-11450-S27999258892000111300000). For testing of EFI main relay, see EFI MAIN RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING - V6 & V8 article. For testing of fuel pump switch, see FUEL PUMP SWITCH under FUEL DELIVERY under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article.
5. If EFI main relay and fuel pump switch are okay, check for defective fuses or wiring. See WIRING DIAGRAMS article. If fuses and wiring are okay, check for defective fuel pump. See appropriate «CHECKING FUEL PUMP OPERATION BY APPLYING BATTERY VOLTAGE TO FUEL PUMP»(ref-11450-S18959551612000111300000). If problem exists in fuel pump ECU or control circuit, Diagnostic Trouble Code (DTC) P1200 may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Scheme 11

Scheme 12

1. Connect hand-held tester to data link connector No. 3. (Scheme 6)and (Scheme 9). Turn ignition on. DO NOT start engine.
2. Turn hand-held tester on. Select ACTIVE TEST MODE on hand-held tester. Using hand-held tester manufacturer's instructions, activate fuel pump. Note location of fuel pressure pulsation damper located at firewall end of driver's side fuel rail. (Scheme 12) Fuel pressure pulsation damper may also be referred to as pulsation damper.
3. Listen for operating sound at in-tank fuel pump and check that screw at center of fuel pressure pulsation damper moves upward due to the fuel pressure. (Scheme 12) If fuel pump operates, check fuel pressure. See «FUEL PRESSURE»(ref-11450-S42112471792000111300000).
4. If fuel pump does not operate, EFI main relay, fuel pump relay or circuit opening relay may be defective. For relay application and explanation of relay operation, see «FUEL PUMP CONTROL CIRCUIT»(ref-11450-S27999258892000111300000). For testing of EFI main relay, fuel pump relay or circuit opening relay, see appropriate relay under MODULES, MOTORS, RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists in fuel pump relay or control circuit, Diagnostic Trouble Code (DTC) P1200 may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.
5. If relays are okay, check for defective fuses, fusible links or wiring. See WIRING DIAGRAMS article. If fuses, fusible links and wiring are okay, check for defective fuel pump. See appropriate «CHECKING FUEL PUMP OPERATION BY APPLYING BATTERY VOLTAGE TO FUEL PUMP»(ref-11450-S30733944862000111300000). If fuel pump operates properly, Engine Control Module (ECM) may be defective. It maybe necessary to check fuel pump resistor. See FUEL PUMP RESISTOR under FUEL DELIVERY under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. NOTE: For additional testing information for fuel pump control circuit, see FUEL PUMP CONTROL CIRCUIT under COMPUTERIZED ENGINE CONTROLS in SYSTEM & COMPONENT TESTING - V6 & V8 article.

Checking Fuel Pump Operation By Applying Battery Voltage To Fuel Pump (Avalon, Camry, Camry Solara, Highlander, Land Cruiser, Sienna, Tacoma & 4Runner)

1. On Avalon, Camry and Camry Solara, remove rear seat cushion, cover plate on floor panel and remaining necessary covers for access to electrical connector for fuel pump.
2. On Highlander, remove driver's side and passenger's side rear seats and cover plate on floor panel for access to electrical connector for fuel pump.
3. On Land Cruiser, remove second seats, rear door scuff plates, step plates, second seat lock covers, rear carpet and cover plate on floor panel for access to electrical connector for fuel pump.
4. On Sienna, manufacturer recommends removing fuel tank for access to fuel pump.
5. On Tacoma, it may be necessary to lower fuel tank for access to electrical connector for fuel pump.
6. On 4Runner, remove driver's side rear seat cushion and cover plate on floor panel for access to electrical connector for fuel pump.
7. On all models, disconnect electrical connector for fuel pump. This is electrical connector for fuel pump and fuel gauge sending unit and is located on top of fuel tank, near fuel pump.
8. Connect battery voltage to specified terminals on fuel pump to activate fuel pump. (Scheme 13)- (Scheme 18). DO NOT apply battery voltage to fuel pump for more than 10 seconds.
9. Listen for fuel pump operating sound. Disconnect battery voltage from fuel pump. If fuel pump operates, check fuel pressure after reinstalling components. See «FUEL PRESSURE»(ref-11450-S42112471792000111300000).
10. If fuel pump fails to operate, replace fuel pump and/or lead wire to fuel pump (if equipped). See FUEL PUMP under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. If fuel pump will not operate while trying to start engine, see appropriate CHECKING FUEL PUMP OPERATION USING TOYOTA HAND-HELD TESTER under «FUEL PUMP OPERATION»(ref-11450-S04663275962000111300000) for additional testing information.

Scheme 13

Scheme 14

Scheme 15

Scheme 16

Scheme 17

Scheme 18

Scheme 19

1. Manufacturer lists checking fuel pump operation with fuel pump removed from fuel tank and fuel pump mounting bracket. For removal of fuel pump from fuel tank and fuel pump mounting bracket, see FUEL PUMP under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
2. Reinstall lead wire on fuel pump. Connect battery voltage to specified terminals on lead wire to activate fuel pump. (Scheme 19) DO NOT apply battery voltage to fuel pump for more than 10 seconds.
3. Listen for fuel pump operating sound. Disconnect battery voltage from lead wire. If fuel pump operates, check fuel pressure after reinstalling fuel pump. See «FUEL PRESSURE»(ref-11450-S42112471792000111300000).
4. If fuel pump fails to operate, replace fuel pump and/or lead wire. If fuel pump will not operate while trying to start engine, see appropriate CHECKING FUEL PUMP OPERATION USING SCAN TOOL under «FUEL PUMP OPERATION»(ref-11450-S04663275962000111300000) for additional testing information.