TM 5-3805-296-23-1
0026
Table 1. 0174 Fuel Temperature Sensor Diagnostic Codes Continued.
026
CID FMI
TEST OR INSPECTION
CORRECTIVE ACTION
NOTE
0174-04 Fuel Temperature
Sensor Voltage Below
Always inspect harness connectors that are involved in the circuit. Poor
Normal
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 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
Engine ECM Detects Below Normal Voltage on Fuel Temp Sensor Signal Circuit
F421.
POSSIBLE CAUSE
Fuel Filter Wiring Harness Shorted.
Engine Interface Wiring Harness Shorted.
Basic Engine Wring Harness Shorted.
Fuel Temperature Sensor.
Engine ECM.
Test Step 1. Test for Shorted Fuel
Temperature Sensor.
1. Turn ignition switch and battery
disconnect switch to OFF position
(TM 5-3805-296-10).
2. Disconnect connector AW-C2
(WP 0012, Figure 38) from fuel
temperature sensor connector
(WP 0012, Figure 37).
3. Turn battery disconnect switch and
ignition switch to ON position
(TM 5-3805-296-10).
4. At MSD, check for active
174-3 Fuel Temperature Sensor Volt-
diagnostic code 174-4 Fuel
age Above Normal Becomes Active
Temperature Sensor Voltage
Replace fuel temperature sensor
Below Normal (WP 0008).
(WP 0226).
Proceed to Test Step 5.
174-4 Fuel Temperature Sensor
Voltage Below Normal Remains
Active Proceed to Test Step 2.