Disconnect generator 4-pin connector. Start engine. Turn on headlights (high beam). Use DVOM to measure voltage between generator 4-pin connector terminal No. 2 (White/Green wire) and battery positive terminal. See Figure. If reading is one volt or less, go to step 3). If reading is greater than one volt, go to next step.
Turn headlights and ignition off. Disconnect 31-pin connector from Powertrain Control Module (PCM), located behind right kick panel. Use DVOM and check continuity of White/Green wire between ground and ECM connector terminal No. 2. See Fig 1. If continuity exists, repair short to ground in White/Green wire. If continuity does not exist, install known good PCM and recheck system. Replace PCM if necessary.
Turn headlights and ignition switch to OFF position. Disconnect 31-pin connector from PCM, located behind right kick panel. Use DVOM and check continuity of White/Green wire between PCM connector terminal No. 2 and 4-pin generator connector terminal No. 2. See Figure and Fig 1. If continuity does not exist, repair open in White/Green wire. If continuity exists, test alternator and regulator. See GENERATOR/REGULATOR OUTPUT TEST .

Fig 1: Identifying ECM/PCM Connector Terminals

Courtesy of AMERICAN HONDA MOTOR CO., INC.

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.

Safety Warning

Generator Control System Test: 3.0CL