Code 1-3-1 (Ignition System Rpm Signal)

Turn ignition off. Disconnect fuel system ECU connector and remove protective sleeve. Connect a voltmeter between harness side of terminal No. 1 (Brown wire on 240 Series and Yellow/Green wire on 740 GL) and ground. Run starter motor. If reading is battery voltage, permanent/magnet generator (engine speed sensor) is okay. If the reading is not battery voltage, check wiring to sensor. If wiring is okay, test permanent/magnetic generator. For permanent/magnetic generator testing, see SYSTEM/COMPONENT TESTS article.