Fault Code Guide

Electrical Pre-Test
Procedure Result Action
Turn off the ignition switch. Check the
ignition ground circuit.
07/21/2004 f544483d
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
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.
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1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
X1
Check for DC voltage from pins 11 and 14
(J1587 datalink) of the X1 connector to the
battery ground terminal.
NOTE: If the meter cannot display the
rapidly shifting DC voltage, measure AC
voltage instead.
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.
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.
07/16/2004 f544483a
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
X1
Freightliner AMT
3
and Mercedes-Benz Automated-Manual
Transmissions
26.03
Troubleshooting Without Fault Codes
Business Class M2 Workshop Manual, Supplement 20, September 2011 301/3