Starter Switch Signal Circuit Troubleshooting

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2005 Honda S2000, 2004 Honda S2000, 2003 Honda S2000, 2002 Honda S2000, and 2001 Honda S2000. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: The clutch pedal must be pressed.

Measure voltage between ECM connector terminals A24 and B20 with the ignition switch in the ON (II) position and the engine start button pressed.

Fig 1: Measuring Voltage Between ECM Connector Terminals A24 And B20 With Ignition Switch
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES - The starter switch signal is OK.
2. NO - Go to step 2.
Inspect the No. 21 STARTER SIGNAL (7.5 A) fuse in the under-dash fuse/relay box.
Is the fuse OK ?
1. YES - Repair open in the wire between the ECM (A24) and the No. 21 STARTER SIGNAL (7.5 A) fuse.
2. NO - Repair short in the wire between the ECM (A24) and the No. 21 STARTER SIGNAL (7.5 A) fuse or the PGM-FI main relay. Replace the No. 21 STARTER SIGNAL (7.5 A) fuse.