Freightliner AMT 3 and Mercedes-Benz Automated-Manual Transmissions 26.03 Troubleshooting Without Fault Codes Electrical Pre-Test Procedure Result Action Turn off the ignition switch. Check the ignition ground circuit. 21 18 15 12 9 6 3 20 17 14 11 8 5 2 19 16 13 10 7 4 1 07/21/2004 f544483d X1 With the ignition switch off, check for resistance between pins 18 and 21 (ground) of the X1 connector and the battery ground terminal. Resistance is greater than 0.3 ohms. Repair or replace the wiring as needed. See Section 54.06 , Subject 100. Resistance is 0.3 ohms or less. Go to the next row in the table. Turn off the ignition switch. Check the J1587 wiring.
21 18 15 12 9 6 3 20 17 14 11 8 5 2 19 16 13 10 7 4 1 X1 07/21/2004 f544483e Check for DC voltage from pins 11 and 14 (J1587 datalink) of the X1 connector to the battery ground terminal. Voltage is less than 1 or more than 4 volt(s) for DC (less than 1 or more than 3 for AC). Troubleshoot the J1587 datalink. NOTE: If the meter cannot display the rapidly shifting DC voltage, measure AC voltage instead. Voltage is between 1 and 4 volts for DC (1–3 volts AC). Go to the next row in the table. Turn off the ignition switch. Check the J1939 wiring. 21 17 18 14 15 12 11 8 9 6 5 2 3 20 19 16 13 10 7 4 1 07/16/2004 f544483a X1 Business Class M2 Workshop Manual, Supplement 20, September 2011 301/3