Table 1. 1251 Alternator R - Terminal Diagnostic Codes.
CID FMI CODE
TEST OR INSPECTION
1251-0 Alternator R Data
Valid but Above Normal
· Always inspect wiring harness connectors that are involved in the circuit.
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 above operating range.
· Engine wiring harness shorted to voltage.
· Lower cab wiring harness shorted to voltage.
· Transmission ECM.
Test Step 1. Check for Active
Diagnostic Code 1251-0 Active -
Transmission 924H and start engine
Proceed to Test Step 2.
(TM 5-3805-298-10). Using MSD,
Diagnostic Code 1251-0 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
2. Disconnect connector R
3. Turn battery disconnect switch to
ON position and start engine