Code No. P0183: Fuel Temperature Sensor Circuit High Input
OPERATION
- A power voltage of 5 V is applied to the fuel temperature sensor output terminal from the engine-ECU connector terminal FTS.
- The power voltage is earthed to the engine-ECU connector terminal FTSE from the fuel temperature sensor connector terminal.
FUNCTION
- The fuel temperature sensor converts the intake air temperature into a voltage and inputs the voltage signal to the engine-ECU.
- In response to the signal, the engine-ECU corrects the fuel injection amount, etc.
- The fuel temperature sensor is a kind of resistor, which has characteristics to reduce its resistance as the intake air temperature rises. Therefore, the sensor output voltage varies with the fuel temperature, and becomes lower as the fuel temperature rises.
TROUBLE JUDGEMENT
Check Conditions
- Battery positive voltage is 8 - 16 V
- 2 seconds later after the ignition switch has been in "ON" position or the engine has started up.
Judgement Criterion
- The fuel temperature sensor output voltage is 4.95 V or more.
FAIL-SAFE AND BACKUP FUNCTION
- The fuel temperature is controlled to be 45°C (start-up of -25°C)
PROBABLE CAUSES
- Failed fuel temperature sensor
- Open circuit or harness damage in fuel temperature sensor circuit or loose connector contact
- Failed engine-ECU
|
|
STEP 1. M.U.T.-III data list
|
|
|
- Item 21: Fuel temperature sensor
|
|
|
OK: At ambient temperature (fuel temperature) or equivalent.
|
|
|
Q.
Is the check result normal?
|
|
|
 Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions).
|
|
|
|
|
|
 Go to Step 2.
|
|
|
|
|
|
STEP 2. Check fuel temperature sensor itself.
|
|
|
- Check fuel temperature sensor itself (Refer to
 ).
|
|
|
Q.
Is the check result normal?
|
|
|
Go to Step 3.
|
|
|
|
|
|
Replace the fuel temperature sensor.
|
|
|
|
|
|
STEP 3. Voltage measurement at fuel temperature sensor connector (FTS line).
|
|
|
(1)Disconnect the connector, and measure at the wiring harness side.
|
|
|
(3)Check the voltage between the fuel temperature sensor connector (FTS line) and body earth.
OK: 4.5 - 4.9 V
|
|
|
Q.
Is the check result normal?
|
|
|
Go to Step 6.
|
|
|
|
|
|
Go to Step 4.
|
|
|
|
|
|
STEP 4. Check of open circuit damage in FTS line between engine-ECU connector and fuel temperature sensor connector.
|
|
|
Q.
Is the check result normal?
|
|
|
Go to Step 5.
|
|
|
|
|
|
Repair the connector(s) or wiring harness.
|
|
|
|
|
|
STEP 5. M.U.T.-III data list
|
|
|
- Item 21: Fuel temperature sensor
|
|
|
OK: At ambient temperature (fuel temperature) or equivalent.
|
|
|
Q.
Is the check result normal?
|
|
|
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions).
|
|
|
|
|
|
Replace the engine-ECU.
|
|
|
|
|
|
STEP 6. Resistance measurement at fuel temperature sensor connector (FTSE line).
|
|
|
(1)Disconnect the connector, and measure at the wiring harness side.
|
|
|
(2)Measure the resistance between the fuel temperature sensor connector (FTSE line) and body earth.
OK: Continuity (2 Ω or less)
|
|
|
Q.
Is the check result normal?
|
|
|
Go to Step 5.
|
|
|
|
|
|
Go to Step 7.
|
|
|
|
|
|
STEP 7. Check of open circuit and damage in FTSE line between engine-ECU connector and fuel temperature sensor connector.
|
|
|
Q.
Is the check result normal?
|
|
|
Go to Step 5.
|
|
|
|
|
|
Repair the connector(s) or wiring harness.
|
|
|
|