[Previous][Next]
DTC P0181: Fuel Tank Temperature Sensor Circuit Range/Performance
 
 
 
 
CIRCUIT OPERATION
  • 5-volt voltage is applied to the fuel tank temperature sensor output terminal from the ECM terminal F/TM via the resistor in the ECM.
  • The fuel tank temperature sensor output voltage increases when the resistance increases and decreases when the resistance decreases. The ground terminal is grounded to the vehicle body.
 
 
TECHNICAL DESCRIPTION
  • The fuel tank temperature sensor converts the fuel tank temperature to a voltage.
  • The ECM detects the fuel tank temperature with this output voltage.
 
 
DESCRIPTIONS OF MONITOR METHODS
  • Fuel tank temperature at engine start is higher than engine coolant temperature at engine start by specified value when engine is cold start condition.
 
 
MONITOR EXECUTION
  • Continuous
 
 
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
  • Not applicable
Sensor (The sensor below is determined to be normal)
  • Engine coolant temperature sensor
  • Intake air temperature sensor
 
 
DTC SET CONDITIONS
Logic Flow Chart
 
 
Check Conditions
  • The engine coolant temperature - intake air temperature is 5°C (9°F) or less when the engine is started.
  • The engine coolant temperature is between
    -10°C (14°F) and 36°C (97°F) when the engine is started.
  • The engine coolant temperature is higher than 60°C (140°F).
  • Maximum vehicle speed is higher than 30 km/h (19 mph) after the engine starting sequence has been completed.
Judgment Criterion
  • The fuel tank temperature - engine coolant temperature is 15°C (27°F) or more when the engine is started.
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • None
 
 
OBD-II DRIVE CYCLE PATTERN
  • Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 14 .
 
 
TROUBLESHOOTING HINTS (The most likely causes for this code to be stored are: )
  • Fuel tank temperature sensor failed.
  • Fuel tank temperature sensor circuit harness damage, or connector damage.
  • ECM failed.
noteA diagnostic trouble code (DTC) could be output if the engine and the radiator have been flushed repeatedly when the engine coolant temperature was high (or the fuel tank temperature was high). Because this is not a failure, the DTC must be erased.
Make sure to test drive the vehicle in accordance with the OBD-II drive cycle pattern in order to verify that a DTC will not be output.

 
 
DIAGNOSIS
Required Special Tools:
  • MB992744: Vehicle Communication Interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite Main Harness A
  • MB992747: V.C.I.-Lite USB Cable Short
  • MB992748: V.C.I.-Lite USB Cable Long
  • MB991958: Scan Tool (M.U.T.-III Sub Assembly)
    • MB991824: Vehicles Communication Interface (V.C.I.)
    • MB991827: M.U.T.-III USB Cable
    • MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)
STEP 1. Using scan tool (M.U.T.-III), check data list item 53: Fuel Tank Temperature Sensor.
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
(1) Connect scan tool (M.U.T.-III). Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III) .
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool (M.U.T.-III) to the data reading mode for item 53, Fuel Tank Temperature Sensor.
  • Approximately the same as the ambient air temperature when the engine is cooled.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the sensor operating properly?
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions .
Go to Step 2.
 
STEP 2. Check the fuel tank temperature sensor.
Refer to GROUP 13C, On-vehicle Service - Fuel Tank Temperature Sensor Check .
Is the measured resistance normal?
Go to Step 3.
Replace the fuel pump module. Then go to Step 6.
 
STEP 3. Check the continuity at fuel tank temperature sensor harness side connector.
(1) Disconnect the fuel pump module connector and measure at the harness side.
(2) Check for the continuity between terminal ground line and ground.
  • Continuity (2 ohms or less)
Does continuity exist?
Go to Step 4.
Repair or replace the connector(s), or check and repair the harness of damage in ground line between fuel pump module connector and ground line. Then go to Step 6.
 
STEP 4. Check of harness damage in F/TM line between fuel pump module connector and ECM connector.
Is the harness wire in good condition?
Go to Step 5.
Repair the connector(s) or wiring harness. Then go to Step 6.
 
STEP 5. Using scan tool (M.U.T.-III), check data list item 53: Fuel Tank Temperature Sensor.
(1) Turn the ignition switch to the "ON" position.
(2) Set scan tool (M.U.T.-III) to the data reading mode for item 53, Fuel Tank Temperature Sensor.
  • Approximately the same as the ambient air temperature when the engine is cooled.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Is the sensor operating properly?
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions .
Replace the ECM (Refer to, Removal and Installation ). Then go to Step 6.
 
STEP 6. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 14 .
(2) Check the diagnostic trouble code (DTC).
Is DTC P0181 stored?
Retry the troubleshooting.
The inspection is complete.