Ignition System - On-Vehicle Inspection

Lexus IS250 IS220d GSE20 ALE20 4GR-FSE IGNITION

IGNITION SYSTEM - ON-VEHICLE INSPECTION

  • NOTICE:
  • In this section, the terms "cold" and "hot" refer to the temperature of the coils. "Cold" means approximately -10 to 50°C (50 to 122°F). "Hot" means approximately 50 to 100°C (122 to 212°F).
1. SPARK PLUG

Check for DTCs.

  • NOTICE:
  • If any DTC is present, perform troubleshooting procedures for that DTC.

Check if sparks occur.

Remove the ignition coils.

Remove the spark plugs.

Install the spark plug to the ignition coil and connect the ignition coil connector.

Disconnect the 6 injector connectors.

Ground the spark plug.

Visually check that sparks occur while the engine is being cranked.

  • NOTICE:
Be sure to ground the spark plug when checking.
If the ignition coil has been struck or dropped, replace it.
Do not crank the engine for more than 2 seconds.

Perform the spark test according to the procedures below:

Check that the wire harness side connector of ignition coil with igniter is securely connected.

  • Result:
  • ResultProceed to
    NGConnect securely
    OKGo to next step

Perform a spark test on each ignition coil with igniter.

1. Exchange the ignition coil with igniter with a normal one.
2. Perform spark test again.
  • Result:
  • ResultProceed to
    OKReplace ignition coil with igniter
    NGGo to next step

Check the power supply to the ignition coil with igniter.

1. Turn the engine switch on (IG).
2. Check that there is battery voltage at the ignition coil positive (+) terminal.
  • Result:
  • ResultProceed to
    NGCheck wiring between engine switch and ignition coil with igniter
    OKGo to next step

Check the VVT sensor output voltage.

  • Result:
  • ResultProceed to
    NGCheck that there is resistance between ECM and VVT sensor. If there is no resistance, replace VVT sensor. If there is resistance, repair wiring between VVT sensor and ECM.
    OKGo to next step

Check the resistance of the crankshaft position sensor.

  • Standard resistance:
  • TemperatureSpecified Condition
    Cold1,630 to 2,740 Ω
    Hot2,065 to 3,225 Ω
  • Result:
  • ResultProceed to
    NGReplace crankshaft position sensor
    OKGo to next step

Check the IGT signal from the ECM.

  • Result:
  • ResultProceed to
    NGCheck ECM
    OKRepair wiring between ignition coil and ECM

Using a 16 mm (0.63 in.) plug wrench, install the spark plug.

  • Torque:
  • 25 N*m{ 254 kgf*cm, 18 ft.*lbf}

Install the ignition coils.

2. INSPECT SPARK PLUG
  • NOTICE:
Do not use a wire brush for cleaning.
Do not attempt to adjust the electrode gap of a used spark plug.
Ignition System - On-Vehicle Inspection. 4GR-FSE IGNITION. Lexus IS250 IS220d GSE20 ALE20

Check the electrode.

Using a megohmmeter, measure the insulation resistance.

  • Insulation resistance:
  • 10 MΩ or more
  • HINT:
  • If a megohmmeter is not available, perform the following simple inspection instead.
Ignition System - On-Vehicle Inspection. 4GR-FSE IGNITION. Lexus IS250 IS220d GSE20 ALE20

Alternative inspection method:

Quickly accelerate the engine to 4,000 rpm 5 times.

Remove the spark plug.

Visually check the spark plug.


If the electrode is dry, the spark plug is functioning properly. If the electrode is damp, proceed to the next step.

Check the spark plug for any damage to its threads and insulator.

  • HINT:
  • If there is any damage, replace the spark plug. If not, reinstall the spark plug.
  • Recommended spark plug:
  • ManufacturerProduct
    DENSO madeFK20HBR11
Ignition System - On-Vehicle Inspection. 4GR-FSE IGNITION. Lexus IS250 IS220d GSE20 ALE20

Check the spark plug electrode gap.

  • Maximum electrode gap for a used spark plug:
  • 1.3 mm (0.051 in.)
    If the gap is greater than the maximum, replace the spark plug.
  • Electrode gap for a new spark plug:
  • 1.0 to 1.1 mm (0.039 to 0.043 in.)
  • NOTICE:
  • If adjusting the gap of a new spark plug, bend only the base of the ground electrode. Do not touch the tip. Never attempt to adjust the gap of a used plug.