1999-2002 TRX400EX Fourtrax Service Manual, Page 231Get this manual
IGNITION SYSTEM
EXCITER COIL PEAK VOLTAGE
NOlE: Check that the cylinder compression is normal and the spark plug is installed correctly in the cylinder headDisconnectthe ignition control module (leM) connectorsConnect the peak voltage tester or adaptor probes to the connector terminals of the wire harness sideCONNECTION:
Turn the ignition switch ONCrank the engine with the starter motor and read the peak voltagePEAK VOLTAGE: 100 minimum
Avoid touching the spark plug and tester probes to prevent electric shock
If the voltage measured at leM connector is abnormal, measure the peak voltage at the exciter coil connectorRemovethe seatrear fender (page 2-2)Disconnectthe exciter coil connector and connect the peak voltage tester or adaptor probes to the alternator side connector terminal and groundIn the same manner as at the ICM connectors, measure the peak voltage and compare it to the voltage measured at the ICM connectorsIf the peak voltage measured at the ICM connectors is abnormal and the one measured at the exciter coil connector is normal, the blackred wire has an open or short circuit, or loose connections If both peak voltages are abnormal, follow the checks described in the troubleshooting on page