TM 5-3805-298-23-1
0109
Table 1. 1251 Alternator R - Terminal Diagnostic Codes - Continued.
0109
CID FMI CODE
TEST OR INSPECTION
CORRECTIVE ACTION
NOTE
1251-8 Alternator R
Abnormal Frequency, Pulse
Always inspect wiring harness connectors that are involved in the circuit.
Width, or Period
Poor connections can often be the cause of a problem in an electrical
circuit. Verify that all connections in the circuit are clean and secure and
that all connections are in good condition. If a problem with the
connection is found, correct the problem and verify that this malfunction
or diagnostic code is active before performing this procedure.
Perform open or short-circuit test at each wiring harness connection to
identify the correct harness to replace.
Tag all wiring harnesses to aid in installation.
Perform this test only if condition is active.
DIAGNOSTIC CODE SET CONDITION
Transmission ECM detects alternator R output is below operating range.
POSSIBLE CAUSE
Alternator.
Engine wiring harness intermittent connection.
Lower cab wiring harness intermittent connection.
Transmission ECM.
Test Step 1. Check for Active
Diagnostic Codes.
Connect MSD (WP 0008). Select
Diagnostic Code 1251-8 Active -
Transmission 924H and start engine
Proceed to Test Step 2.
(TM 5-3805-298-10). Using MSD,
Diagnostic Code 1251-8 Not Active -
check for active diagnostic codes
Troubleshooting is complete.
Test Step 2. Test Alternator Output R.
1. Turn ignition switch and battery
disconnect switch to OFF position
(TM 5-3805-298-10).
2. Disconnect connector R
(WP 0012, Figure 92) from
alternator.
3. Turn battery disconnect switch to
ON position and start engine
(TM 5-3805-298-10).
4. Using digital multimeter
Voltage 11 to 32 VAC Proceed to
(WP 0174), test for AC voltage
Test Step 3.
between alternator terminal R stud
Voltage Less Than 11 VAC Replace
and ground.
alternator (WP 0238).
Proceed to Test Step 7.
