Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSTOYOTA2006SEQUOIA 4WD V8-4.7L (2UZ-FE)REPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTIGNITION SYSTEMTESTING AND INSPECTION
2006 Toyota Sequoia 4WD V8-4.7L (2UZ-FE)
Ignition System: Testing and Inspection
2006 Toyota Sequoia 4WD V8-4.7L (2UZ-FE)SECTION Testing and Inspection
ON-VEHICLE INSPECTION
NOTE: "Cold" and "Hot" in these sentences express the temperature of the coils themselves. "Cold" is from -10 degree C (14 degree F) to 50 degree C (122 degree F) and "Hot" is from 50 degree C (122 degree F) to 100 degree C (212 degree F).
1. INSPECT IGNITION COIL (WITH IGNITER) AND SPARK TEST
a. Check that the spark occurs.
1. Remove the ignition coils (with igniter).
2. Remove the spark plugs.
3. Install the spark plugs to each ignition coil (with igniter), and connect the ignition coil (with igniter) connector.
4. Disconnect the 8 injector connectors.
5. Ground the spark plug.
6. Check that spark occurs while engine is being cranked.
NOTE: To prevent gasoline from being injected out of injectors during this test, crank the engine for no more than 5 to 10 seconds at a time.
b. Perform the spark test according to the flowchart.
1. Check that the wire harness side connector of the ignition coil with igniter is securely connected.
2. Perform a spark test on each ignition coil with igniter.
1. Replace the ignition coil with igniter with a normal one.
2. Perform the spark test again.
3. Check the power supply to the ignition coil with igniter.
1. Turn the ignition switch ON.
2. Check that there is battery voltage at the ignition coil positive (+) terminal.
4. Check the resistance of the crankshaft position sensor.
5. Check IGT signal from the ECM.
c. Using a 16 mm plug wrench, install the 8 spark plugs.
Torque: 17.5 N.m (178 kgf.cm, 13 ft.lbf)
d. Reinstall the ignition coils (with igniter).
2. INSPECT SPARK PLUGS
a. Remove the ignition coils (with igniter).
b. Using a 16 mm plug wrench, remove the spark plugs.
c. Clean the spark plugs.
If the electrode has traces of wet carbon, allow it to dry and then clean with a spark plug cleaner.
Air pressure:
Below 588 kPa (6 kgf/sq.cm, 85 psi)
Duration:
20 seconds or less
HINT: If there are traces of oil, remove it with gasoline before using the spark plug cleaner.
d. Check the spark plug for thread damage and insulator damage.
If abnormal, replace the spark plug.
e. Adjust the spark plug electrode gap.
Electrode gap for new spark plug:
1.0 to 1.1 mm (0.039 to 0.043 in.)
f. Using a 16 mm plug wrench, install the spark plugs.
Torque: 17.5 N.m (180 kgf.cm, 13 ft.lbf)
g. Reinstall the ignition coils (with igniter).
NOTE: "Cold" and "Hot" in these sentences express the temperature of the coils themselves. "Cold" is from -10 degree C (14 degree F) to 50 degree C (122 degree F) and "Hot" is from 50 degree C (122 degree F) to 100 degree C (212 degree F).
1. INSPECT IGNITION COIL (WITH IGNITER) AND SPARK TEST
a. Check that the spark occurs.
1. Remove the ignition coils (with igniter).
2. Remove the spark plugs.
3. Install the spark plugs to each ignition coil (with igniter), and connect the ignition coil (with igniter) connector.
4. Disconnect the 8 injector connectors.
5. Ground the spark plug.
6. Check that spark occurs while engine is being cranked.
NOTE: To prevent gasoline from being injected out of injectors during this test, crank the engine for no more than 5 to 10 seconds at a time.
b. Perform the spark test according to the flowchart.
1. Check that the wire harness side connector of the ignition coil with igniter is securely connected.
2. Perform a spark test on each ignition coil with igniter.
1. Replace the ignition coil with igniter with a normal one.
2. Perform the spark test again.
3. Check the power supply to the ignition coil with igniter.
1. Turn the ignition switch ON.
2. Check that there is battery voltage at the ignition coil positive (+) terminal.
4. Check the resistance of the crankshaft position sensor.
5. Check IGT signal from the ECM.
c. Using a 16 mm plug wrench, install the 8 spark plugs.
Torque: 17.5 N.m (178 kgf.cm, 13 ft.lbf)
d. Reinstall the ignition coils (with igniter).
2. INSPECT SPARK PLUGS
a. Remove the ignition coils (with igniter).
b. Using a 16 mm plug wrench, remove the spark plugs.
c. Clean the spark plugs.
If the electrode has traces of wet carbon, allow it to dry and then clean with a spark plug cleaner.
Air pressure:
Below 588 kPa (6 kgf/sq.cm, 85 psi)
Duration:
20 seconds or less
HINT: If there are traces of oil, remove it with gasoline before using the spark plug cleaner.
d. Check the spark plug for thread damage and insulator damage.
If abnormal, replace the spark plug.
e. Adjust the spark plug electrode gap.
Electrode gap for new spark plug:
1.0 to 1.1 mm (0.039 to 0.043 in.)
f. Using a 16 mm plug wrench, install the spark plugs.
Torque: 17.5 N.m (180 kgf.cm, 13 ft.lbf)
g. Reinstall the ignition coils (with igniter).
RENDER: 1.0x
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.