TM 5-3805-298-23-1
0098
Table 1. 637 Backup Alarm Diagnostic Codes - Continued.
098
CID FMI CODE
TEST OR INSPECTION
CORRECTIVE ACTION
6. Using MSD, check for active
637-3 Backup Alarm Circuit
Diagnostic Code 637-3 Backup
diagnostic codes (WP 0008).
Voltage Is Above Normal -
Alarm Circuit Voltage Is Above
Continued
Normal Becomes Inactive -
Troubleshooting complete.
Diagnostic Code 637-3 Backup
Alarm Circuit Voltage Is Above
Normal Remains Active - Repeat
troubleshooting from the beginning.
NOTE
637-5 Backup Alarm Circuit
Current Below 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 wiring 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 an open circuit or low current condition in the backup
alarm circuit.
POSSIBLE CAUSE
Lower cab wiring harness high resistance or open.
Rear frame wiring harness high resistance or open.
Backup alarm faulty.
Test Step 1. Check for Active
Diagnostic Codes.
1. Connect MSD. Select
Transmission 924H (WP 0008).
2. Turn military light switch to
SER. DRIVE position (TM 5-3805-
298-10).
