Brake Pedal Position Switch Signal Circuit Troubleshooting

Check the brake lights.
Are the brake lights on without pressing the brake pedal?
1. YES - Inspect the brake pedal position switch (see Brake Pedal & Brake Pedal Position Switch Adjustment ).
2. NO - Go to step 2.
Press the brake pedal.
Do the brake lights come on?
1. YES - Go to step 3.
2. NO - Go to step 4.
Measure voltage between ECM/PCM connector terminals A32 and B20 with the brake pedal pressed.

Fig 1: Measuring Voltage Between ECM/PCM Connector Terminals A32 & B20
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES - The brake pedal position switch signal is OK.
2. NO - Repair open in the wire between the ECM/PCM (A32) and the brake pedal position switch.
Inspect the STOP (20A) fuse in the under-hood fuse/relay box.
Is the fuse OK?
1. YES - Repair open in the wire between the brake pedal position switch and the STOP (20 A) fuse. Inspect the brake pedal position switch (see Brake Pedal & Brake Pedal Position Switch Adjustment ).
2. NO - Repair short in the wire between the ECM/PCM (A32) and the STOP (20A) fuse. Replace the STOP (20A) fuse.