√ Fuel Temperature Sensor - Voltage Above Normal
CID 0174 FMI 03 Fuel Temperature Open/Short to +Batt
|Figure 1.1 - Fuel Temp Sensor Open (174-3)|
MID 036 CID 0174 FMI 03
The troubleshooting procedures for the diagnostic codes of each temperature sensor are identical. The temperature sensors are passive sensors that have two terminals. The temperature sensors do not require supply voltage from the Electronic Control Module (ECM).
Conditions Which Generate This Code:
The Electronic Control Module (ECM) detects signal voltage that is above normal.
The ECM will log the diagnostic code. The ECM flags fuel temperature as invalid data and a default value is used.
Possible Performance Effect:
- Connecting Caterpillar ET to the ECM (in this case: C-15 Engine). Read More: How to Connecting Caterpillar ET Software to the ECM.
- Check for Active Diagnostic Codes, found Error Code: 174-3. Read More: Sensor Diagnostics on Electronic Engines.
|Figure 1.2 - Fuel Temperature Sensor: Voltage Above Normal (1)|
A). Perform the following diagnostic procedure:
- Disconnect the Fuel Temperature Sensor at the sensor connector (keyswitch: ON position).
- Measure the voltage between terminal 1 (sensor signal) and terminal 2 (sensor return) at the sensor connector. In this case, Pull-Up voltage is OK (The voltage is 5.5 ± 0.5 VDC). Read More: PULL-UP Voltage and How the ECM Uses it to Determine Diagnostic Conditions.
|Figure 1.3 - Fuel Temperature Sensor: Voltage Above Normal (2)|
- Create a Short at the Fuel Temperature Sensor connector (keyswitch: ON position).
- Check for active diagnostic codes on Caterpillar ET. Record any active diagnostic codes. Wait at least 15 seconds for activation of the short circuit diagnostic code -04 or Voltage Below Normal. In this case, a short circuit diagnostic code -04 (174-4) is active when the jumper wire is installed, and an open circuit diagnostic code -03 is active when the jumper wire is removed (The engine harness and the ECM are OK).
|Figure 1.4 - Fuel Temperature Sensor: Voltage Below Normal|
|Figure 1.5 - Fuel Temp Sensor Short (174-4)|
B). Measure the resistance of the sensor (M ohms), also indicates an open circuit.
-Replace the Fuel Temperature Sensor, with CAT P/N: 197-8391