Alternator and Regulator Circuit Troubleshooting

K24A1, K20A4 (KE, KG, KS models) engines

1.Be sure the battery connections are good, and that the battery is sufficiently charged.

2.Raise the hoist to full height.

3.Hook up the ammeter, 0-400 A, to the starter subharness.


4.Lower the hoist.

5.Hook up the voltmeter, 0-20 V (accurate within 0.1 V), to T101.


6.Start the engine. Hold the engine at 3,000 rpm (min-1), with no load until the radiator fan comes on, then let it idle.

7.Raise the engine speed to 2,000 rpm (min-1) and hold it there.

8.Turn the headlights (high beam) on, and measure voltage at the under-hood fuse/relay box terminal.

Is the voltage between 13.9 and 15.1 V?

YES - Go to 9.

NO - Replace the alternator or repair the alternator.n

9.Read the amperage at 13.5 V.

NOTE: Adjust the voltage by turning the blower motor, rear window defogger, brake lights, etc. ON.

Is the amperage 60A or more?

YES - Alternator/regulator operation is OK. Go to Alternator Control Circuit Troubleshooting.n

NO - Replace the alternator or repair the alternator.n