Engine Controls - Basic Diagnostic Procedures - V6 & V8: Other Toyota Sienna I

ENGINE IMMOBILIZER SYSTEM AVAILABILITY

Note. An engine immobilizer system may be used. Engine immobilizer system is a theft deterrent system which disables the engine from starting by not allowing ignition system operation and fuel injector operation unless ignition key identification code matches identification code stored in Engine Control Module (ECM). Engine immobilizer system may be standard feature or optional feature on specified models. See ENGINE IMMOBILIZER SYSTEM AVAILABILITY table. For additional information on system operation and testing, see appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.

ENGINE IMMOBILIZER SYSTEM AVAILABILITY

Compression

Warm engine to normal operating temperature before checking the compression. Ensure battery is fully charged. Remove ignition coils and spark plugs. See IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. Check engine mechanical condition with a compression gauge, vacuum gauge, or engine analyzer with throttle fully open. See engine analyzer manual for specific instructions. See COMPRESSION SPECIFICATIONS table. Reinstall ignition coils. Install and tighten spark plugs to 13 ft. lbs. (18 N.m).

COMPRESSION SPECIFICATIONS

FUEL SYSTEMS

Basic diagnosis of fuel system should begin by checking fuel pump operation and fuel pressure.

Avalon, Camry & Camry Solara

1. Remove rear seat cushion, cover plate on floor panel and remaining necessary covers for access to electrical connector for fuel pump. Disconnect electrical connector for fuel pump. This is electrical connector for fuel pump and fuel gauge sending unit.
2. Start engine and allow engine to idle until engine stalls. Turn ignition off. Reinstall electrical connector for fuel pump, necessary covers, cover plate and rear seat cushion.
3. Disconnect negative battery cable. Place suitable container under fuel line connection. Cover fuel line connection with shop towel. Slowly loosen fuel line connection or disconnect fuel line connection, allowing any fuel pressure to be released. Once fuel pressure is released, fuel system components may be serviced.

Land Cruiser

1. Disconnect electrical connector for fuel pump. (Scheme 31) This is electrical connector for fuel pump and fuel gauge sending unit. Start engine and allow engine to idle until engine stalls. Turn ignition off. Reinstall electrical connector for fuel pump.
2. Disconnect negative battery cable. Place suitable container under fuel line connection. Cover fuel line connection with shop towel. Slowly loosen fuel line connection or disconnect fuel line connection, allowing any fuel pressure to be released. Once fuel pressure is released, fuel system components may be serviced.

Scheme 31

Sienna

1. Disconnect negative battery cable. Place container below fuel line connection at fuel filter. Cover fuel line connection with shop towel.
2. Slowly loosen fuel line connection to allow fuel pressure to be released. Once fuel pressure is released, fuel system components may be serviced. Reinstall negative battery cable after service procedures are performed.

Tacoma, Tundra & 4Runner

1. 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. Start engine and allow engine to idle until engine stalls. Turn ignition off. Reinstall electrical connector for fuel pump.
2. Disconnect negative battery cable. Place suitable container under fuel line connection. Cover fuel line connection with shop towel. Slowly loosen fuel line connection, allowing any fuel pressure to be released. Once fuel pressure is released, fuel system components may be serviced.

Scheme 32

1. Ensure battery is fully charged. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-2890-S25837158112000041400000). Disconnect negative battery cable.
2. On Avalon, purchase a No. 1 fuel pipe Part No. (23801-20070) from parts department. On Camry and Camry Solara, purchase a No. 1 fuel pipe Part No. (23801-20041) from parts department. On all models, No. 1 fuel pipe is fuel pipe that attaches to top of fuel filter. Remove fuel pipe connector from end of NEW No. 1 fuel pipe. (Scheme 32)
3. Remove fuel pipe clamp from No. 1 fuel pipe at fuel filter. Perform STEP 1. (Scheme 33) Ensure area around No. 1 fuel pipe and fuel filter is clean. CAUTION: Use care when disconnecting No. 1 fuel pipe from fuel filter, as some residual fuel pressure may still exist in the fuel system.
4. Depress both sides of retainer and pull No. 1 fuel pipe with disconnect fitting from fuel filter. Perform STEP 2. (Scheme 33)
5. Install adapter, hose and fuel pressure gauge from Fuel Pressure Gauge Set (SST 09268-45012) with fuel pipe connector between No. 1 fuel pipe and fuel filter. (Scheme 34) Ensure hose, No. 1 fuel pipe and fuel pipe connector are properly connected.
6. Install negative battery cable. Connect scan tool to data link connector No. 3. see scheme 1- see scheme 3. Turn ignition on. DO NOT start engine.
7. Turn scan tool on. Select ACTIVE TEST MODE on scan tool. Using scan tool manufacturer's instructions, activate fuel pump and note fuel pressure. Fuel pressure should be 44-50 psi (3.1-3.5 kg/cm 2 ). NOTE: Fuel pump may also be activated by connecting battery voltage to specified terminals on fuel pump. see scheme 11
8. If fuel pressure is within specification, go to next step. If fuel pressure exceeds specification, replace fuel pressure regulator mounted on fuel pump in the fuel tank. See FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. If fuel pressure is less than specified, check for leaking fuel hoses or connections, restricted fuel filter, defective fuel pump or defective fuel pressure regulator.
9. Remove scan tool from data link connector No. 3. Start engine and note fuel pressure with engine idling. Fuel pressure should be 44-50 psi (3.1-3.5 kg/cm 2 ). Shut engine off and note fuel pressure. Fuel pressure should remain at least 21 psi (1.5 kg/cm 2 ) for a minimum of 5 minutes. If fuel pressure is within specification and holds as specified, go to next step. If fuel pressure is not within specification or does not hold as specified, check for defective fuel pump, fuel injector or fuel pressure regulator.
10. Release fuel pressure. Disconnect negative battery cable. Remove adapter, hose, fuel pressure gauge and fuel pipe connector. CAUTION: DO NOT reuse old retainer when installing No. 1 fuel pipe on fuel filter. Always use a NEW retainer.
11. Apply light coat of engine oil on tip of pipe on fuel filter to allow for ease of disconnect fitting and No. 1 fuel pipe installation. Using NEW retainer, install No. 1 fuel pipe on fuel filter until "click" sound is heard. DO NOT reuse old retainer. Pull on No. 1 fuel pipe to ensure fuel pipe is properly locked on fuel filter.
12. Reinstall fuel pipe clamp until "click" sound is heard. Pull upward on fuel pipe clamp to ensure fuel pipe clamp is securely locked on fuel filter. Install negative battery cable. Check for fuel leaks by using scan tool to energize fuel pump.

Scheme 33

Scheme 34

1. Ensure battery is fully charged. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-2890-S25837158112000041400000). Disconnect negative battery cable.
2. Remove intake manifold cover located on top of engine, above intake manifold. Intake manifold cover must be removed for access front fuel pipe at front of driver's side fuel rail. (Scheme 35)
3. Cover union bolt at front fuel pipe at front of driver's side fuel rail with shop towel. Remove union bolt with gaskets, and disconnect front fuel pipe from front of driver's side fuel rail. It may be necessary to remove retaining bolt at center of front fuel pipe when disconnecting front fuel pipe from driver's side fuel rail.
4. Install Union (SST 90405-06167), Adapter (SST 09268-41190) and fuel pressure gauge from Fuel Pressure Gauge Set (SST 09268-45012) with front fuel pipe on driver's side fuel rail. (Scheme 36) Tighten adapter to 29 ft. lbs. (39 N.m).
5. Install negative battery cable. Connect scan tool to data link connector No. 3. see scheme 8 Turn ignition on. DO NOT start engine.
6. Turn scan tool on. Select ACTIVE TEST MODE on scan tool. Using scan tool manufacturer's instructions, activate fuel pump and note fuel pressure. Fuel pressure should be 38-44 psi (2.7-3.1 kg/cm 2 ). NOTE: Fuel pump may also be activated by connecting battery voltage to specified terminals on fuel pump. see scheme 12
7. If fuel pressure is within specification, go to next step. If fuel pressure exceeds specification, replace fuel pressure regulator mounted near center of passenger's side fuel rail. See FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. If fuel pressure is less than specified, check for leaking fuel hoses or connections, restricted fuel filter, defective fuel pump or defective fuel pressure regulator.
8. Remove scan tool from data link connector No. 3. Start engine. Disconnect and plug vacuum hose at fuel pressure regulator mounted near center of passenger's side fuel rail. Note fuel pressure with engine idling. Fuel pressure should be should be 38-44 psi (2.7-3.1 kg/cm 2 ).
9. Reinstall vacuum hose on fuel pressure regulator. Note fuel pressure with engine idling. Fuel pressure should be 28-34 psi (2.0-2.4 kg/cm 2 ). If fuel pressure is within specification, go to next step. If fuel pressure is not within specification, check for defective vacuum hose or fuel pressure regulator.
10. Shut engine off and note fuel pressure. Fuel pressure should remain at least 21 psi (1.5 kg/cm 2 ) for a minimum of 5 minutes. If fuel pressure holds as specified, go to next step. If fuel pressure does not hold as specified, check for defective fuel pump, fuel injector or fuel pressure regulator.
11. Release fuel pressure. Disconnect negative battery cable. Remove adapter, union and fuel pressure gauge from driver's side fuel rail. Using NEW gaskets, install front fuel pipe on driver's side fuel rail. Tighten union bolt to 29 ft. lbs. (39 N.m) and retaining bolt for front fuel pipe (if loosened) to 66 INCH lbs. (7.5 N.m).
12. Install negative battery cable. Check for fuel leaks by using scan tool to energize fuel pump. Install intake manifold cover.

Scheme 35

Scheme 36

1. Ensure battery is fully charged. Release fuel pressure by loosening union bolt at top of fuel filter. See «FUEL SYSTEM PRESSURE RELEASE»(ref-2890-S25837158112000041400000).
2. Note location of fuel pressure gauge installation on fuel filter. (Scheme 37) Remove union bolt and gaskets from fuel filter. Install fuel pressure gauge from Fuel Pressure Gauge Set (SST 09268-45012) with gaskets and union bolt on fuel filter. (Scheme 37) Tighten union bolt to 21 ft. lbs. (29 N.m).
3. Reconnect negative battery cable. Connect scan tool to data link connector No. 3. see scheme 4 Turn ignition on. DO NOT start engine.
4. Turn scan tool on. Select ACTIVE TEST MODE on scan tool. Using scan tool manufacturer's instructions, activate fuel pump and note fuel pressure. Fuel pressure should be 44-50 psi (3.1-3.5 kg/cm 2 ). NOTE: Fuel pump may also be activated by connecting battery voltage to specified terminals on fuel pump. see scheme 13
5. If fuel pressure is within specification, go to next step. If fuel pressure exceeds specification, replace fuel pressure regulator mounted on fuel pump in the fuel tank. See FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. If fuel pressure is less than specified, check for leaking fuel hoses or connections, restricted fuel filter, defective fuel pump or defective fuel pressure regulator.
6. Remove scan tool from data link connector No. 3. Start engine and note fuel pressure with engine idling. Fuel pressure should be 44-50 psi (3.1-3.5 kg/cm 2 ).
7. Shut engine off and note fuel pressure. Fuel pressure should remain at least 21 psi (1.5 kg/cm 2 ) for a minimum of 5 minutes. If fuel pressure is within specification and holds as specified, go to next step. If fuel pressure is not within specification or does not hold as specified, check for defective fuel pump, fuel injector or fuel pressure regulator.
8. Release fuel pressure. Disconnect negative battery cable. Remove fuel pressure gauge. Using NEW gaskets, reinstall fuel inlet hose on fuel filter. Tighten union bolt to 21 ft. lbs. (29 N.m).
9. Install negative battery cable. Check for fuel leaks by using scan tool to energize fuel pump.

Scheme 37

Tacoma, Tundra 3.4L V6 & 4Runner

1. Ensure battery is fully charged. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-2890-S25837158112000041400000).
2. Disconnect negative battery cable. Remove bolts, upper timing belt cover and gasket for access to fuel pipe at front of driver's side fuel rail for installation of fuel pressure gauge. (Scheme 38) Cover union bolt on fuel pipe at front of driver's side fuel rail with shop towel. Remove union bolt with gaskets, and disconnect fuel pipe from front of driver's side fuel rail.
3. Install union, union bolt and fuel pressure gauge from Fuel Pressure Gauge Set (SST 09268-45012) with fuel pipe on driver's side fuel rail. (Scheme 38) Tighten union bolt to 25 ft. lbs. (34 N.m).
4. Install negative battery cable. Connect scan tool to data link connector No. 3. see scheme 5- see scheme 7. Turn ignition on. DO NOT start engine.
5. Turn scan tool on. Select ACTIVE TEST MODE on scan tool. Using scan tool manufacturer's instructions, activate fuel pump and note fuel pressure. Fuel pressure should be 38-44 psi (2.7-3.1 kg/cm 2 ). NOTE: On Tacoma and 4Runner, fuel pump may also be activated by connecting battery voltage to specified terminals on fuel pump. see scheme 14and see scheme 15.
6. On all models, if fuel pressure is within specification, go to next step. If fuel pressure exceeds specification, replace fuel pressure regulator mounted at firewall end of driver's side fuel rail. See FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. If fuel pressure is less than specified, check for leaking fuel hoses or connections, restricted fuel filter, defective fuel pump or defective fuel pressure regulator.
7. Remove scan tool from data link connector No. 3. Reinstall No. 2 timing belt cover. Start engine. Disconnect and plug vacuum hose at fuel pressure regulator mounted at firewall end of driver's side fuel rail. Note fuel pressure with engine idling. Fuel pressure should be should be 38-44 psi (2.7-3.1 kg/cm 2 ).
8. Reinstall vacuum hose on fuel pressure regulator. Note fuel pressure with engine idling. Fuel pressure should be 33-38 psi (2.3-2.7 kg/cm 2 ). If fuel pressure is within specification, go to next step. If fuel pressure is not within specification, check for defective vacuum hose or fuel pressure regulator.
9. Shut engine off and note fuel pressure. Fuel pressure should remain at least 21 psi (1.5 kg/cm 2 ) for a minimum of 5 minutes. If fuel pressure holds as specified, go to next step. If fuel pressure does not hold as specified, check for defective fuel pump, fuel injector or fuel pressure regulator.
10. Release fuel pressure. Disconnect negative battery cable. Remove upper timing belt cover. Remove union bolt, union and fuel pressure gauge from driver's side fuel rail. Using NEW gaskets, install fuel pipe on driver's side fuel rail. Tighten union bolt to 25 ft. lbs. (34 N.m). Reinstall upper timing belt cover. Tighten bolts to 80 INCH lbs. (9.0 N.m).
11. Install negative battery cable. Check for fuel leaks by using scan tool to energize fuel pump.

Scheme 38

Tundra 4.7L V8

1. Ensure battery is fully charged. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-2890-S25837158112000041400000). Disconnect negative battery cable.
2. Remove throttle body cover and intake air connector for access to front fuel pipe at front of driver's side fuel rail (if necessary). (Scheme 35) Intake air connector fits between throttle body and air cleaner assembly.
3. Cover union bolt at front fuel pipe at front of driver's side fuel rail with shop towel. Remove union bolt with gaskets, and disconnect front fuel pipe from front of driver's side fuel rail. It may be necessary to remove retaining bolt at center of front fuel pipe when disconnecting front fuel pipe from driver's side fuel rail.
4. Install Union (SST 90405-06167), Adapter (SST 09268-41190) and fuel pressure gauge from Fuel Pressure Gauge Set (SST 09268-45012) with front fuel pipe on driver's side fuel rail. (Scheme 36) Tighten adapter to 29 ft. lbs. (39 N.m).
5. Install negative battery cable. Connect scan tool to data link connector No. 3. see scheme 6 Turn ignition on. DO NOT start engine.
6. Turn scan tool on. Select ACTIVE TEST MODE on scan tool. Using scan tool manufacturer's instructions, activate fuel pump and note fuel pressure. Fuel pressure should be 38-44 psi (2.7-3.1 kg/cm 2 ).
7. If fuel pressure is within specification, go to next step. If fuel pressure exceeds specification, replace fuel pressure regulator mounted near center of passenger's side fuel rail. See FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. If fuel pressure is less than specified, check for leaking fuel hoses or connections, restricted fuel filter, defective fuel pump or defective fuel pressure regulator.
8. Remove hand-held tester from data link connector No. 3. Start engine. Note fuel pressure with engine idling. Fuel pressure should be 38-44 psi (2.7-3.1 kg/cm 2 ).
9. Shut engine off and note fuel pressure. Fuel pressure should remain at least 21 psi (1.5 kg/cm 2 ) for a minimum of 5 minutes. If fuel pressure holds as specified, go to next step. If fuel pressure does not hold as specified, check for defective fuel pump, fuel injector or fuel pressure regulator.
10. Release fuel pressure. Disconnect negative battery cable. Remove adapter, union and fuel pressure gauge from driver's side fuel rail. Using NEW gaskets, install front fuel pipe on driver's side fuel rail. Tighten union bolt to 29 ft. lbs. (39 N.m) and retaining bolt for front fuel pipe (if loosened) to 66 INCH lbs. (7.5 N.m).
11. Install negative battery cable. Check for fuel leaks by activating the fuel pump by using hand-held tester or connecting battery voltage to fuel pump. Reinstall remaining components.
12. Install negative battery cable. Check for fuel leaks by using scan tool to energize fuel pump. Install throttle body cover and intake air connector (if removed).

FUEL PUMP CONTROL CIRCUIT

Note. For information on testing relays and fuel system components, see SYSTEM & COMPONENT TESTING - V6 & V8 article. Circuit opening relay is used on all models except Land Cruiser. Circuit opening relay may be identified by appropriate illustration in SYSTEM & COMPONENT TESTING - V6 & V8 article. For complete wiring circuit of electrical components on a specific model, see appropriate wiring diagram in WIRING DIAGRAMS article.

Circuit Opening Relay (Avalon)

Circuit opening relay controls fuel pump circuit. When EFI main relay is energized, EFI main relay provides battery voltage to one side of circuit opening relay. When ignition is turned on, voltage is supplied from ignition switch to other side of circuit opening relay. When proper input signals are delivered to Engine Control Module (ECM), circuit opening relay ground circuit is grounded at ECM terminal FC. Circuit opening relay then provides voltage to fuel pump for fuel pump operation. For circuit opening relay location, see CIRCUIT OPENING RELAY LOCATION table.

Circuit Opening Relay (Camry, Camry Solara & Sienna)

Circuit opening relay controls fuel pump circuit. When EFI main relay is energized, EFI main relay provides battery voltage to one side of circuit opening relay. When ignition is turned on, voltage is supplied through IGN fuse to other side of circuit opening relay. When proper input signals are delivered to Engine Control Module (ECM), circuit opening relay ground circuit is grounded at ECM terminal FC. Circuit opening relay then provides voltage to fuel pump for fuel pump operation. For circuit opening relay location, see CIRCUIT OPENING RELAY LOCATION table.

Circuit Opening Relay (Tacoma)

Circuit opening relay controls fuel pump circuit. When EFI main relay is energized, EFI main relay provides battery voltage to one side of circuit opening relay. When engine is cranking, circuit opening relay receives a start signal which energizes circuit opening relay. Circuit opening relay then provides voltage to fuel pump for fuel pump operation. When start signal is released from circuit opening relay, Engine Control Module (ECM) then controls the ground circuit for circuit opening relay at ECM terminal FC. Circuit opening relay then provides voltage to fuel pump for fuel pump operation. For circuit opening relay location, see CIRCUIT OPENING RELAY LOCATION table.

Circuit Opening Relay (Tundra 3.4L V6)

Circuit opening relay controls fuel pump circuit. When EFI main relay is energized, EFI main relay provides battery voltage to both sides of circuit opening relay. When proper input signals are delivered to Engine Control Module (ECM), circuit opening relay ground circuit is grounded at ECM terminal FC. Circuit opening relay then provides voltage to fuel pump for fuel pump operation. For circuit opening relay location, see CIRCUIT OPENING RELAY LOCATION table.

Circuit Opening Relay (Tundra 4.7L V8)

Circuit opening relay controls fuel pump circuit by supplying voltage to fuel pump relay. When EFI main relay is energized, EFI main relay provides battery voltage to one side of circuit opening relay. When ignition is turned on, voltage is supplied through IGN fuse to other side of circuit opening relay. When proper input signals are delivered to Engine Control Module (ECM), circuit opening relay ground circuit is grounded at ECM terminal FC. Circuit opening relay then provides voltage to fuel pump relay which supplies voltage to fuel pump for fuel pump operation. For circuit opening relay location, see CIRCUIT OPENING RELAY LOCATION table. For operation of fuel pump relay, see FUEL PUMP RELAY & FUEL PUMP RESISTOR (TUNDRA 4.7L V8) under FUEL PUMP CONTROL CIRCUIT.

Circuit Opening Relay (4Runner)

Circuit opening relay controls fuel pump circuit. When EFI main relay is energized, EFI main relay provides battery voltage to both sides of circuit opening relay. When proper input signals are delivered to Engine Control Module (ECM), circuit opening relay ground circuit is grounded at ECM terminal FC. Circuit opening relay then provides voltage to fuel pump for fuel pump operation. For circuit opening relay location, see CIRCUIT OPENING RELAY LOCATION table.

CIRCUIT OPENING RELAY LOCATION (1)

EFI Main Relay (Avalon)

EFI main relay may also be referred to as EFI relay. EFI No. 1 fuse supplies constant battery voltage to one side of EFI main relay. EFI main relay is energized by MREL terminal of Engine Control Module (ECM). When EFI main relay is energized, EFI main relay provides battery voltage to circuit opening relay, data link connector No. 1 and various other electrical components. EFI main relay also provides battery voltage to +B terminal of ECM. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment, near battery and air cleaner.

EFI Main Relay (Camry & Camry Solara)

EFI main relay may also be referred to as EFI relay. EFI fuse supplies constant battery voltage to one side of EFI main relay. EFI main relay is energized by MREL terminal of Engine Control Module (ECM). When EFI main relay is energized, EFI main relay provides battery voltage to circuit opening relay, data link connector No. 1 and various other electrical components. EFI main relay also provides battery voltage to +B terminal of ECM. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment, near battery and air cleaner.

EFI Main Relay (Land Cruiser)

EFI main relay may also be referred to as EFI relay or ECD relay. EFI fuse supplies constant battery voltage to one side of EFI main relay. EFI fuse may also be referred to as ECD fuse. EFI main relay is energized by MREL terminal of Engine Control Module (ECM). When EFI main relay is energized, EFI main relay provides battery voltage to +B terminal of fuel pump Electronic Control Unit (ECU) and various other electrical components. EFI main relay also provides battery voltage to +B and +B1 terminals of ECM. For operation of fuel pump ECU and fuel pump switch, see FUEL PUMP ELECTRONIC CONTROL UNIT (ECU) & FUEL PUMP SWITCH (LAND CRUISER) under FUEL PUMP CONTROL CIRCUIT. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment, near battery.

EFI Main Relay (Sienna)

EFI main relay may also be referred to as EFI relay. EFI fuse supplies constant battery voltage to one side of EFI main relay. EFI main relay is energized by MREL terminal of Engine Control Module (ECM). When EFI main relay is energized, EFI main relay provides battery voltage to circuit opening relay, data link connector No. 1 and various other electrical components. EFI main relay also provides battery voltage to +B terminal of ECM. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment, near battery and air cleaner.

EFI Main Relay (Tacoma)

EFI main relay may also be referred to as EFI relay. EFI fuse supplies constant battery voltage to one side of EFI main relay. On Calif. emission vehicles, EFI main relay is energized by MREL terminal of Engine Control Module (ECM). On except Calif. emission vehicles, when ignition is turned on, voltage is supplied through IGN fuse to other side of EFI main relay and EFI main relay is then energized. On all models, when EFI main relay is energized, EFI main relay provides battery voltage to circuit opening relay, data link connector No. 1 and various other electrical components. EFI main relay also provides battery voltage to +B terminal of Engine Control Module (ECM) when ignition is turned on. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment, next to battery.

EFI Main Relay (Tundra 3.4L V6)

EFI main relay may also be referred to as EFI relay. EFI fuse No. 1 supplies constant battery voltage to one side of EFI main relay. On Calif. emission vehicles, EFI main relay is energized by MREL terminal of Engine Control Module (ECM). On except Calif. emission vehicles, when ignition is turned on, voltage is supplied through IGN fuse to other side of EFI main relay and EFI main relay is then energized. On all models, when EFI main relay is energized, EFI main relay provides battery voltage to circuit opening relay, data link connector No. 1 and various other electrical components. EFI main relay also provides battery voltage to +B terminal of ECM. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment, next to battery.

EFI Main Relay (Tundra 4.7L V8)

EFI main relay may also be referred to as EFI relay. EFI fuse No. 1 supplies constant battery voltage to one side of EFI main relay. EFI main relay is energized by MREL terminal of Engine Control Module (ECM). When EFI main relay is energized, EFI main relay provides battery voltage to circuit opening relay, through EFI fuse No. 2 and to data link connector No. 1 and various other electrical components. EFI main relay also provides battery voltage to +B and +B1 terminals of ECM. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment, next to battery.

EFI Main Relay (4Runner)

EFI main relay may also be referred to as EFI relay. EFI fuse supplies constant battery voltage to one side of EFI main relay. EFI main relay is energized by MREL terminal of Engine Control Module (ECM). When EFI main relay is energized, EFI main relay provides battery voltage to circuit opening relay, data link connector No. 1 and various other electrical components. EFI main relay also provides battery voltage to +B terminal of ECM. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment, next to battery.

Fuel Pump Electronic Control Unit (ECU) & Fuel Pump Switch (Land Cruiser)

Fuel pump operating speed is controlled by engine operating conditions such as: starting, idling, light load or heavy load. Engine Control Module (ECM) delivers an input signal from FPC terminal on ECM to FPC terminal on fuel pump ECU in accordance with engine operating condition. Fuel pump ECU uses this input signal to determine how much voltage should be delivered to fuel pump for varying fuel pump operating speed.

When engine starts, or engine is under heavy load at high speeds, ECM delivers input signal of approximately 3.8 volts to fuel pump ECU. Fuel pump ECU then delivers approximately battery voltage to fuel pump and fuel pump operates at high speed. When engine is under heavy load at low speeds, ECM delivers an input signal of approximately 2.5 volts to fuel pump ECU. Fuel pump ECU then delivers approximately 10 volts to fuel pump and fuel pump operates at medium speed. When engine is idling or under light loads, ECM delivers an input signal of approximately 1.3 volts to fuel pump ECU. Fuel pump ECU then delivers approximately 8.5 volts to fuel pump and fuel pump operates at low speed. If a problem exists in fuel pump ECU or control circuit, Diagnostic Trouble Code (DTC) P1200 may be stored in ECM. See SELF-DIAGNOSTICS - INTRODUCTION article for retrieving and servicing of DTCs. Fuel pump ECU is located behind inner panel, just behind driver's rear wheelwell. (Scheme 39)

Note. Fuel pump switch may also be referred to as fuel pump inertia switch or fuel pump control switch.

Fuel pump switch is in the circuit between FPC terminal on ECU and FPC terminal on fuel pump ECU. Fuel pump switch may also be referred to as fuel pump inertia switch or fuel pump control switch. If vehicle is involved in a collision, fuel pump switch will shut off the fuel pump by opening this circuit, and not allowing any input signal to be delivered from ECM to fuel pump ECU. Fuel pump switch is located on driver's side of instrument panel. (Scheme 40) Fuel pump switch contains a reset switch which has an OFF and ON position. (Scheme 40) Continuity will exist between electrical terminals on fuel pump switch with reset switch in the ON position, and no continuity in the OFF position. Reset switch must be in ON position for fuel pump operation.

Scheme 39

Scheme 40

Fuel Pump Relay & Fuel Pump Resistor (Tundra 4.7L V8)

Fuel pump operating speed is controlled by operating condition of the engine such as: starting, idling, light load or heavy load. When engine is cranking and start signal is received at Engine Control Module (ECM), the ECM energizes circuit opening relay and voltage is applied to both sides of fuel pump relay. Fuel pump relay contacts are closed on one side and voltage is applied directly to fuel pump in which fuel pump operates at high speed. After engine starts during idling or light loads, fuel pump relay is energized by FPR terminal of ECM and contacts in fuel pump relay close to other side of relay. Voltage is then supplied to fuel pump by going from fuel pump relay through fuel pump resistor. Fuel pump now operates at low speed. Fuel pump relay is located in fuse/relay box at driver's side front corner of engine compartment, next to battery. Fuel pump resistor is located at driver's side front corner of engine compartment, near end of fuse/relay box. (Scheme 41)

Scheme 41

IGNITION SYSTEMS

Note. All models use a distributorless ignition system.

Avalon

1. Remove ignition coils. See IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
2. Remove spark plugs. Install spark plug on each ignition coil. Reinstall electrical connectors on ignition coils. Ground spark plugs against cylinder block. CAUTION: To prevent gasoline from being injected, DO NOT crank engine for longer than 5 seconds when checking for spark.
3. Crank engine and check for spark. If spark does not exist, check ignition coil electrical connections. If electrical connections are okay, go to next step. If electrical connections are defective, repair as necessary and recheck for spark.
4. Install different ignition coil on spark plug and recheck for spark. If spark still does not exist, go to next step. If spark now exists with different ignition coil, replace original ignition coil.
5. Turn ignition on. Using voltmeter, check for battery voltage at ignition coil positive terminal. See appropriate wiring diagram in WIRING DIAGRAMS article. If battery voltage exists, go to next step. If battery voltage does not exist, check wiring between ignition switch and ignition coil. NOTE: It may be necessary to check operation of IG2 relay by using wiring diagram. See appropriate wiring diagram in WIRING DIAGRAMS article. IG2 fuse supplies constant battery voltage to one side of IG2 relay. When ignition is turned on, voltage is supplied from ignition switch to other side of IG2 relay and IG2 relay is then energized. When IG2 relay is energized, IG2 relay provides battery voltage to ignition coils and fuel injectors. IG2 relay is located in fuse/relay box at driver's side front corner of engine compartment, near battery and air cleaner.
6. Check resistance of camshaft position sensor. See «CAMSHAFT POSITION SENSOR RESISTANCE»(ref-2890-S20093075992000041400000) . If camshaft position sensor resistance is within specification, go to next step. If camshaft position sensor resistance is not within specification, replace camshaft position sensor. See IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
7. Check resistance of crankshaft position sensor. See «CRANKSHAFT POSITION SENSOR RESISTANCE»(ref-2890-S00581711982000041400000) . If crankshaft position sensor resistance is within specification, go to next step. If crankshaft position sensor resistance is not within specification, replace crankshaft position sensor. See IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
8. Check ignition IGT signal from Engine Control Module (ECM) to ignition coil. If ignition IGT signal from ECM is defective, Diagnostic Trouble Code (DTC) P1300, P1305, P1310, P1315, P1320 or P1325 will be set in ECM memory to indicate an ignitor circuit malfunction. See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article for retrieving of DTCs.
9. If ignition IGT signal is okay, substitute another ignition coil and recheck system operation. If ignition IGT signal is defective, check wiring between ECM and ignition coil. See «ECM LOCATION»(ref-2890-S12295261332000041400000) table. If wiring is defective, repair wiring as necessary and recheck system operation. If wiring is okay, substitute another ECM and recheck system operation. Reinstall components.

Scheme 42

1. Remove ignition coils. See IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
2. Reinstall electrical connectors and spark plug wires on ignition coils. Remove spark plugs. Install spark plug on each ignition coil and each spark plug wire. Ground spark plugs against cylinder block. CAUTION: To prevent gasoline from being injected, DO NOT crank engine for longer than 5 seconds when checking for spark.
3. Crank engine and check for spark. If spark exists at spark plug on ignition coil, but not on spark plug on spark plug wire, go to next step. If spark does not exist on any spark plug, check ignition coil and ignitor electrical connections. See «IGNITOR LOCATIONS»(ref-2890-S03127794012000041400000) table. If electrical connections are okay, go to step 5. If electrical connections are defective, repair as necessary and recheck for spark. IGNITOR LOCATIONS Application Location Camry & Camry Solara In Engine Compartment, Near Driver's Side Strut Tower Sienna (1) (1) Ignitor is located below front cowl in engine compartment. (Scheme 42)
4. Using ohmmeter, check resistance of spark plug wire. Replace spark plug wire if resistance exceeds 25,000 ohms per wire.
5. Turn ignition on. Using voltmeter, check for battery voltage at ignitor and ignition coil positive terminal. See appropriate wiring diagram in WIRING DIAGRAMS article. If battery voltage exists, go to next step. If battery voltage does not exist, check wiring between ignition switch, ignition coil and ignitor.
6. Check ignition coil resistance. See «IGNITION COIL RESISTANCE»(ref-2890-S24070496262000041400000). If ignition coil resistance is within specification, go to next step. If ignition coil resistance is not within specification, replace ignition coil.
7. Check resistance of camshaft position sensor. See «CAMSHAFT POSITION SENSOR RESISTANCE»(ref-2890-S20093075992000041400000). If camshaft position sensor resistance is within specification, go to next step. If camshaft position sensor resistance is not within specification, replace camshaft position sensor. See IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
8. Check resistance of crankshaft position sensor. See «CRANKSHAFT POSITION SENSOR RESISTANCE»(ref-2890-S00581711982000041400000). If crankshaft position sensor resistance is within specification, go to next step. If crankshaft position sensor resistance is not within specification, replace crankshaft position sensor. See IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
9. Check ignition IGT signal from Engine Control Module (ECM) to ignitor. If ignition IGT signal from ECM is defective, Diagnostic Trouble Code (DTC) P1300 will be set in ECM memory to indicate an ignitor circuit malfunction. See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article for retrieving of DTCs.
10. If ignition IGT signal is okay, substitute another ignitor and recheck system operation. If ignition IGT signal is defective, check wiring between ECM and ignitor. See «ECM LOCATION»(ref-2890-S12295261332000041400000) table. If wiring is defective, repair wiring as necessary and recheck system operation. If wiring is okay, substitute another ECM and recheck system operation. Reinstall components. Install and tighten spark plugs to 13 ft. lbs. (18 N.m).

Land Cruiser & Tundra 4.7L V8

1. Remove ignition coils. See IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
2. Remove spark plugs. Install spark plug on each ignition coil. Reinstall electrical connectors on ignition coils. Ground spark plugs against cylinder block. CAUTION: To prevent gasoline from being injected, electrical connectors should be disconnected from fuel injectors. DO NOT crank engine for longer than 5 seconds when checking for spark.
3. Disconnect electrical connectors at fuel injectors. Crank engine and check for spark. If spark does not exist, check electrical connection at ignition coil. If electrical connection is okay, go to next step. If electrical connection is defective, repair as necessary and recheck for spark.
4. Install different ignition coil on spark plug and recheck for spark. If spark still does not exist, go to next step. If spark now exists with different ignition coil, replace original ignition coil.
5. Turn ignition on. Using voltmeter, check for battery voltage at ignition coil positive terminal. See appropriate wiring diagram in WIRING DIAGRAMS article. If battery voltage exists, go to next step. If battery voltage does not exist, check wiring between ignition switch and ignition coil.
6. Check resistance of camshaft position sensor. See «CAMSHAFT POSITION SENSOR RESISTANCE»(ref-2890-S20093075992000041400000) . If camshaft position sensor resistance is within specification, go to next step. If camshaft position sensor resistance is not within specification, replace camshaft position sensor. See IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
7. Check resistance of crankshaft position sensor. See «CRANKSHAFT POSITION SENSOR RESISTANCE»(ref-2890-S00581711982000041400000) . If crankshaft position sensor resistance is within specification, go to next step. If crankshaft position sensor resistance is not within specification, replace crankshaft position sensor. See IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
8. Check ignition IGT signal from Engine Control Module (ECM) to ignition coil. If ignition IGT signal from ECM is defective, Diagnostic Trouble Code (DTC) P1300, P1305, P1310, P1315, P1320, P1325, P1330 or P1340 will be set in ECM memory to indicate a specified ignitor circuit malfunction. See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article for retrieving of DTCs.
9. If ignition IGT signal is okay, substitute another ignition coil and recheck system operation. If ignition IGT signal is defective, check wiring between ECM and ignition coil. See «ECM LOCATION»(ref-2890-S12295261332000041400000) table. If wiring is defective, repair wiring as necessary and recheck system operation. If wiring is okay, substitute another ECM and recheck system operation. Reinstall components. Install and tighten spark plugs to 13 ft. lbs. (18 N.m).

1. Remove spark plugs and install spark plug on each spark plug wire. Ground spark plug against cylinder block. CAUTION: To prevent gasoline from being injected, DO NOT crank engine for longer than 5 seconds when checking for spark.
2. Crank engine and check for spark. If spark does not exist, check ignition coil and ignitor electrical connections. Ignitor is located at passenger's side front of engine compartment, near airflow meter and air cleaner assembly. If electrical connections are okay, go to next step. If electrical connections are defective, repair as necessary and recheck for spark.
3. Using ohmmeter, check resistance of spark plug wire. Replace spark plug wire if resistance exceeds 25,000 ohms per wire. If resistance is within specification, go to next step.
4. Turn ignition on. Check for battery voltage at ignitor and ignition coil positive terminal. See appropriate wiring diagram in WIRING DIAGRAMS article. If battery voltage exists, go to next step. If battery voltage does not exist, check wiring between ignition switch, ignition coil and ignitor.
5. Check ignition coil resistance. See «IGNITION COIL RESISTANCE»(ref-2890-S24070496262000041400000) . If ignition coil resistance is within specification, go to next step. If ignition coil resistance is not within specification, replace ignition coil. See IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
6. Check resistance of camshaft position sensor. See «CAMSHAFT POSITION SENSOR RESISTANCE»(ref-2890-S20093075992000041400000) . If camshaft position sensor resistance is within specification, go to next step. If camshaft position sensor resistance is not within specification, replace camshaft position sensor. See IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
7. Check resistance of crankshaft position sensor. See «CRANKSHAFT POSITION SENSOR RESISTANCE»(ref-2890-S00581711982000041400000) . If crankshaft position sensor resistance is within specification, go to next step. If crankshaft position sensor resistance is not within specification, replace crankshaft position sensor. See IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
8. Check ignition IGT signal from Engine Control Module (ECM) to ignitor. If ignition IGT signal from ECM is defective, Diagnostic Trouble Code (DTC) P1300 will be set in ECM memory to indicate an ignitor circuit malfunction. See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article for retrieving of DTCs.
9. If ignition IGT signal is okay, substitute another ignitor and recheck system operation. If ignition IGT signal is defective, check wiring between ECM and ignitor. See «ECM LOCATION»(ref-2890-S12295261332000041400000) table. If wiring is defective, repair wiring as necessary and recheck system operation. If wiring is okay, substitute another ECM and recheck system operation. Reinstall components. Install and tighten spark plugs to 13 ft. lbs. (18 N.m).

ECM LOCATION

Ignition coil test procedure and resistance are not available from manufacturer.

Camry, Camry Solara, Sienna, Tacoma, Tundra 3.4L V6 & 4Runner

1. To check ignition coil primary resistance, remove necessary components for access to ignition coil. Disconnect electrical connector at ignition coil.
2. To disconnect spark plug wire at ignition coil, use screwdriver to lift lock claw upward. (Scheme 43) Disconnect holder at ignition coil. Pull upward on grommet to disconnect spark plug wire from ignition coil. (Scheme 44) DO NOT pull on spark plug wire.
3. Using ohmmeter, check ignition coil primary resistance between positive (+) and negative (-) electrical terminals on ignition coil. (Scheme 45) These are electrical terminals on ignition coil that electrical connector was installed on. Replace ignition coil if ignition coil primary resistance is not within specification. See «IGNITION COIL RESISTANCE»(ref-2890-S36644785052000041400000) table.
4. To check ignition coil secondary resistance, remove ignition coil. See IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. Using ohmmeter, check ignition coil secondary resistance. (Scheme 46) Replace ignition coil if ignition coil secondary resistance is not within specification. See «IGNITION COIL RESISTANCE»(ref-2890-S36644785052000041400000) table.
5. Reinstall ignition coil. When installing spark plug wire on ignition coil, ensure spline on ignition coil aligns with spline on holder and install spark plug wire. Ensure holder is properly positioned on grommet and ignition coil. (Scheme 44) Lightly pull upward on holder to ensure lock claw is securely locked in place.

Ignition coil test procedure and resistance are not available from manufacturer.

IGNITION COIL RESISTANCE - Ohms

Scheme 43

Scheme 44

Scheme 45

Scheme 46

Scheme 47

1. Two camshaft position sensors are used. Camshaft position sensors are located at flywheel end of each cylinder head, just below valve cover. (Scheme 47) Camshaft position sensors may also be referred to Variable Valve Timing (VVT) sensors. Disconnect electrical connector at camshaft position sensor.
2. Using ohmmeter, check resistance between electrical terminals on camshaft position sensor. (Scheme 47) Ensure camshaft position sensor resistance is within specification. See «CAMSHAFT POSITION SENSOR RESISTANCE»(ref-2890-S13355666672000041400000) table. Replace camshaft position sensor if resistance is not within specification. See IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. Reinstall electrical connector on camshaft position sensor.

Scheme 48

1. Disconnect electrical connector at camshaft position sensor. Camshaft position sensor is located at flywheel end of front cylinder head, just below valve cover. (Scheme 48)
2. Using ohmmeter, check resistance between electrical terminals on camshaft position sensor. (Scheme 48) Ensure camshaft position sensor resistance is within specification. See «CAMSHAFT POSITION SENSOR RESISTANCE»(ref-2890-S13355666672000041400000) table. Replace camshaft position sensor if resistance is not within specification. See IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. Reinstall electrical connector on camshaft position sensor.

Scheme 49

1. Camshaft position sensor is located behind driver's side upper timing belt cover with electrical connector near front of upper timing belt cover. (Scheme 49) On Land Cruiser, remove intake manifold cover located on top of engine, above intake manifold for access to electrical connector for camshaft position sensor.
2. On all models, disconnect electrical connector at camshaft position sensor, Using ohmmeter, check resistance between electrical terminals on electrical connector for camshaft position sensor. (Scheme 49)
3. Ensure camshaft position sensor resistance is within specification. See «CAMSHAFT POSITION SENSOR RESISTANCE»(ref-2890-S13355666672000041400000) table. Replace camshaft position sensor if resistance is not within specification. See IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. Reinstall electrical connector for camshaft position sensor.

Scheme 50

1. Disconnect electrical connector for camshaft position sensor located near upper radiator hose. (Scheme 50) Camshaft position sensor is located behind upper timing belt cover, near passenger's side camshaft sprocket.
2. Using ohmmeter, check resistance between electrical terminals on electrical connector for camshaft position sensor. (Scheme 50) Ensure camshaft position sensor resistance is within specification. See «CAMSHAFT POSITION SENSOR RESISTANCE»(ref-2890-S13355666672000041400000) table. Replace camshaft position sensor if resistance is not within specification. See IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. Reinstall electrical connector for camshaft position sensor.

CAMSHAFT POSITION SENSOR RESISTANCE

Scheme 51

1. Disconnect electrical connector at crankshaft position sensor. Crankshaft position sensor is located at front of crankshaft, near crankshaft pulley. (Scheme 51)
2. Manufacturer lists inspection procedure with crankshaft position sensor removed before checking the resistance. Remove bolt and crankshaft position sensor.
3. Using ohmmeter, check resistance between electrical terminals on crankshaft position sensor. Replace crankshaft position sensor if resistance is not within specification. See «CRANKSHAFT POSITION SENSOR RESISTANCE»(ref-2890-S04116553802000041400000) table.
4. Reinstall crankshaft position sensor. Install and tighten crankshaft position sensor bolt to 71 INCH lbs. (8.0 N.m). Reinstall electrical connector on crankshaft position sensor.

Scheme 52

1. Crankshaft position sensor is located at front of crankshaft, near crankshaft pulley. (Scheme 52) Manufacturer recommends removing crankshaft position sensor before checking the resistance.
2. Remove lower engine cover for access to crankshaft position sensor. Disconnect electrical connector at crankshaft position sensor. Remove bolt and crankshaft position sensor.
3. Using ohmmeter, check resistance between electrical terminals on crankshaft position sensor. Replace crankshaft position sensor if resistance is not within specification. See «CRANKSHAFT POSITION SENSOR RESISTANCE»(ref-2890-S04116553802000041400000) table.
4. Reinstall crankshaft position sensor. Install and tighten crankshaft position sensor bolt to 58 INCH lbs. (6.6 N.m). Reinstall electrical connector and lower engine cover.

Scheme 53

1. Crankshaft position sensor is located at front of engine, just above crankshaft pulley. (Scheme 53) Manufacturer lists inspection procedure with crankshaft position sensor removed before checking the resistance.
2. Remove lower engine cover for access to crankshaft position sensor. Disconnect electrical connector at crankshaft position sensor. Remove bolt and crankshaft position sensor.
3. Using ohmmeter, check resistance between electrical terminals on crankshaft position sensor. Replace crankshaft position sensor if resistance is not within specification. See «CRANKSHAFT POSITION SENSOR RESISTANCE»(ref-2890-S04116553802000041400000) table.
4. Reinstall crankshaft position sensor. Install and tighten crankshaft position sensor bolt to 69 INCH lbs. (7.8 N.m). Reinstall electrical connector and lower engine cover. CRANKSHAFT POSITION SENSOR RESISTANCE Application Ohms All Models Cold (1) 1630-2740 Hot (2) 2065-3225 (1) Cold is with temperature of 14-122°F (-10-50°C). (2) Hot is with temperature of 122-212°F (50-100°C).

IDLE SPEED & IGNITION TIMING

Ensure idle speed and ignition timing are set to specification. For adjustment procedures, see ON-VEHICLE ADJUSTMENTS - V6 & V8 article.

SUMMARY

If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, proceed to appropriate SELF-DIAGNOSTICS article. If no hard diagnostic trouble codes are found in self-diagnostics, proceed to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.