GS300 & Is300

WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2003 Lexus SC 430, 2003 Lexus RX 300, 2003 Lexus LX 470, 2003 Lexus LS 430, and 2003 Lexus IS 300. However, it is still accessible from the selected car via links, so may be relevant.

Remove ignition coil. See IGNITION SYSTEM in REMOVAL & INSTALLATION - EXCEPT GX470 article.
Using ohmmeter, check ignition coil primary resistance between positive (+) and negative (-) electrical terminals on ignition coil. See Fig 1. Replace ignition coil if ignition coil primary resistance is not within specification. See IGNITION COIL RESISTANCE (OHMS) table.

Using ohmmeter, check ignition coil secondary resistance between electrical terminal and spark plug terminal on ignition coil. See Fig 2. Replace ignition coil if ignition coil secondary resistance is not within specification. See IGNITION COIL RESISTANCE (OHMS) table. Reinstall ignition coil.

IGNITION COIL RESISTANCE (OHMS)

Application

Primary

Secondary

GS300 & IS300

Cold ⁽¹⁾

.33-.52

8500-14,700

Hot ⁽²⁾

.42-.61

10,800-17,200

⁽¹⁾	Cold is with coolant temperature of 14-122°F (-10-50°C).

⁽²⁾	Hot is with coolant temperature of 123-212°F (51-100°C).

Fig 1: Checking Ignition Coil Primary Resistance (GS300 & IS300)

Fig 2: Checking Ignition Coil Secondary Resistance (GS300 & IS300)