Fuel Temp Sensor Circuit - High Input

DTC P0183 Fuel Temp Sensor A Circuit High Input

General Description
The fuel temperature sensor is located in the fuel tank for detecting the fuel tank temperature. The fuel temperature sensor uses a thermistor whose resistance changes with the temperature. The electrical resistance of the fuel temperature sensor decreases as the temperature increases, and increases as the temperature decreases. The reference 5V in the ECM is supplied to the fuel temperature sensor via a resistor in the ECM. The resistor in the ECM and the thermistor in the fuel temperature sensor are connected in series. When the resistance value of the thermistor in the fuel temperature sensor changes with variations in fuel tank temperature, the output voltage also changes.

DTC Description
If fuel temperature sensor's signal is higher than 4.6V, the ECM determines that a fault exists and a DTC is stored.

Specification:

DTC Detecting Condition:

Terminal and Connector Inspection
1. Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?

YES
- Repair as necessary and go to "Verification of Vehicle Repair" procedure below.

NO
- Go to " Signal Circuit Inspection " procedure below.

Signal Circuit Inspection
1. Check for Voltage
(1) Ignition "OFF".
(2) Disconnect Fuel pump connector.
(3) Ignition "ON" & Engine "OFF".





(4) Measure voltage between terminal "2" of Fuel pump harness connector and chassis ground.
Specification : Approx. 5V
(5) Is the measured voltage within specifications?

YES
- Go to " Ground Circuit Inspection" procedure below.

NO
- Go to "Check for open in harness" below.

2. Check for open in harness
(1) Ignition "OFF".
(2) Disconnect Fuel pump connector.





(3) Measure resistance between terminal "2" of Fuel pump harness connector and terminal "C26" of ECM harness connector.
Specification : Approx. below 1 ohm
(4) Is the measured resistance within specifications?

YES
- Go to "Ground Circuit Inspection" procedure below.

NO
- Check for open in harness.
- Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure below.

Ground Circuit Inspection
1. Check for open in harness
(1) Ignition "OFF".
(2) Disconnect Fuel pump connector and ECM connector.





(3) Measure resistance between terminal "6" of Fuel pump harness connector and chassis ground.
Specification : Approx. below 1 ohm
(4) Is the measured resistance within specifications?

YES
- Go to " Component Inspection " procedure.

NO
- Check for open in harness.
- Repair or replace as necessary and then, go to " Verification of Vehicle Repair " procedure below.

Component Inspection
1. Ignition "OFF"
2. Disconnect Fuel Pump connector.





3. Measure resistance between terminal "2" and "6" of the Fuel Pump connector (To Component Side).
A. Specification : At 0° C (32°F), Resistance 4 ~ 7 k/ohms
At 20°C (68°F), Resistance 2 ~ 3 k/ohms
At 40° C (104°F), Resistance 0.9 ~ 1.3 k/ohms
At 80° C (176°F), Resistance 0.2 ~ 0.4 k/ohms
4. Is the measured resistance of FTS within specifications?

YES
- Substitute with a known - good ECM and check for proper operation. If the problem is corrected, replace ECM and go to "Verification of Vehicle Repair" procedure below.

NO
- Substitute with a known - good FTS and check for proper operation. If the problem is corrected, replace FTS and go to "Verification of Vehicle Repair" procedure below.

Verification of Vehicle Repair
After a repair, it is essential to verify that the fault has been corrected.
1. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code (DTC) which has been diagnosed.
2. Using a Scantool, Clear the DTCs.
3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions.
4. Monitor that all readiness test have been verified as " Complete "
5. Are any DTCs present?

YES
- Go to the applicable troubleshooting procedure.
NO
- System is performing to specification at this time.