Possible Cause: 1. Alternator W terminal not connected to machine wire harness. 2. Faulty Alternator. 3. Faulty wire harness.
Diagnosis: 1. Check the connection between wire harness & alternator W Terminal. Wire harness shall be connected on the alternator connector as shown in below Photog
2.Check the alternator frequency on the W terminal by help of multimeter. Alternator frequency can be measure on the W terminal of alternator as shown in below photograph.
3. Check the Alternator frequency on the circuit no 4221 connected on pin no 34 Of MECU wire harness connector with help of multimeter after disconnecting MECU wire harness connector. Refer below photograph. Corrective Action: 1. Connect the wire harness with the alternator properly. 2. Replace faulty alternator. 3. Replace Faulty Wire harness.