Fix P0183: Mechanic’s solutions that WORKED

The P0183: Fuel Temperature Sensor Circuit High Input code indicates an issue in the fuel temperature sensor circuit, specifically signaling that the input is too high. This sensor measures the temperature of the fuel in the vehicle, which is important for efficient engine performance. A high input signal suggests that the sensor is not functioning correctly, either due to a faulty sensor, wiring issues, or circuit problems.

P0183 quick overview

Meaning	P0183: Fuel Temperature Sensor Circuit High Input
Is it serious?	This code can indicate a potential issue with the fuel system, which may affect vehicle performance and fuel efficiency.
Possible causes	– Faulty fuel temperature sensor – Wiring or connector issues to the sensor – Circuit problems like shorts or open circuits – Physical damage to the sensor or its wiring – Incorrect voltage supply to the sensor
How to diagnose?	Check Sensor and Wiring: Inspect the fuel temperature sensor and its wiring for damage or corrosion. Verify Voltage and Ground: Ensure proper voltage at the sensor and a good ground connection. Test Sensor Resistance: Measure the sensor’s resistance to ensure it’s within specifications. Look for Circuit Issues: Investigate potential shorts or open circuits in the sensor’s circuit. Address Environmental Damage: Check for any environmental damage like water ingress or rodent damage.

How to fix P0183 – learn from mechanics

I looked into P0183 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Subaru

Vehicle Information: 1998 Subaru Legacy GT 2.5L – Fuel temp sensor issue

Issue + Repair History:

• P0183 fuel temp sensor A fault code.
• Fault reappears after clearing, on the next key cycle.
• Broken valve found near the front passenger corner of the tank, with inlet and outlet nipples and a two-pin electrical connector.
• Uncertainty if the broken valve is related to the P0183 fault.
• Previous repair: Fuel tank replaced two months ago with one from a 1997 Legacy GT due to a major fuel leak.

Suggestions to Fix Issue:

1. Check the fuel temp sensor at the fuel pump connector, particularly pins 5 and 6.
2. The broken valve is an EVAP pressure control solenoid valve and likely not related to the P0183 fault.
3. The fuel temp sensor is located on the fuel pump, with wiring through the fuel pump connector.
4. Inspect the connector under the trunk carpet square access hole as a starting point.

Final Fix:

• The fuel temp sensor was diagnosed as faulty (less than 5 ohms).
• The broken valve, unrelated to the P0183 fault, was replaced.
• The solution was found by checking the sensor’s location in the fuel tank, which was overlooked initially.

Case #2: Hyundai

Vehicle Information: 2003 Hyundai Santa Fe GLS 3.5L – MIL Lamp on

Issue + Repair History:

• Code P0183: fuel temperature sensor circuit A high.
• Mitchell information system does not list this code.
• Code reappears every morning after being cleared.
• Tested fuel temperature sensor wires on the 2-prong connector at fuel pump (red and black wires).

Other OBD2 Codes + Test Results:

• P0183: Fuel Temperature Circuit A High
• Connectors at the fuel pump module were found to be clean and tight.

Suggestions to Fix Issue:

1. Fuel temperature sensor might be open; check for 2400-2500 ohms resistance at 68 degrees F.
2. Sensor located on the fuel pump module, red and black wires.
3. Check for no voltage drop across the black (ground) wire.
4. Red wire is a 5-volt feed, should drop down as temperature changes.
5. Disconnect wire from tank unit and measure resistance across the sender.
6. Consider the possibility of a faulty sensor or wiring issue if voltage is out of range (0.5 to 4.5 volts).

Final Fix:

• Information from the Hyundai motor service website helped diagnose the problem.
• The fuel temperature sensor had an open circuit only when the vehicle sat outside overnight.
• Thanks to community suggestions and the Hyundai service site, the issue was resolved.

Case #3: Subaru

Vehicle Information: 2001 Subaru Outback VDC 3.0L – MIL Lamp on

Issue + Repair History:

• Code P0164 for fuel level sensor set 4 weeks ago.
• After clearing, the code reset in a week.
• Fuel level sensor showed irregular resistance changes and sometimes lost continuity, leading to its replacement.
• Light reset again after four days, despite replacing the sensor and sub-assembly.
• Harness and connectors were inspected for damage; ground and signal from the ECU checked and found good.
• Customer reported light comes on randomly and sometimes at startup.
• Both fuel level sensors and fuel temp sensor replaced.
• Complete harness inspection conducted.

Other OBD2 Codes + Test Results:

• P0464: Fuel Level Sensor
• P0183: Fuel Temp Sensor

Suggestions to Fix Issue:

1. Replace both fuel level sensors, as Subaru wagons often use two.
2. Consider reprogramming the ECM at the dealer, especially for federal vehicles under warranty.

Final Fix:

• Cleaned and tightened all grounds during inspection.
• Customer reported no recurrence of the issue for 15 days.
• If the issue recurs, plan to reprogram the ECM at the dealer as suggested.

Case #4: Mitubishi

Vehicle Information: 2002 Mitsubishi Lancer ES 2.0L – MIL Lamp on

Issue + Repair History:

• Code P0183: Fuel temperature sensor circuit high input.
• Replaced fuel temperature sensor due to unstable ohm readings.
• After replacement, the code reappeared.
• Connection at sensor checked, along with PCM ground and 5-volt reference.

Suggestions to Fix Issue:

1. Check for loose connections, particularly at connector D-14, and between the sensor and the PCM.
2. Inspect for bent male pins inside connectors, especially the one on top of the fuel tank.
3. Test the circuit for a possible short to power.
4. Wiggle harnesses in the circuit to check for intermittent issues.
5. Verify the entire fuel temperature circuit and ensure the correct sensor was replaced.

Final Fix:

• Initially found voltage around 5 volts, then observed over 6 volts at the sensor.
• Discovered a short: Voltage at ECM was 4.77 volts, but at the sensor, it rose to battery voltage.
• Found water under the carpet, leading to connector C-127 in the left front kick panel being very wet.
• After drying the connector, voltage normalized.
• Learned that half of the windshield was not sealed properly, allowing water ingress.
• Issue resolved by addressing the water problem and sealing the windshield.

Case #5: Nissan

Vehicle Information: 2003 Nissan 350Z Track 3.5L – Cuts out

Issue + Repair History:

• Car limited to revving no higher than 1500-1800 rpm.
• Codes found: P0605 (PCM ROM error) and P0183 (fuel temp. signal high).
• Replaced PCM, but issue persisted.
• C1131 engine fuel cut system fault in the ABS system.
• TPMS system filled with codes due to custom wheels, but not considered an issue by the customer.
• Fuel gauge not working for a couple of years.
• Further inspection found wire at pump connector chewed through by rodents.

Computer Codes & Descriptions:

• P0605: PCM ROM error
• P0183: Fuel temp signal too high
• C1131: Engine fuel cut system fault

Suggestions to Fix Issue:

1. Perform relearns for accelerator position, throttle valve closed position, and idle air volume.
2. Check for open circuit in fuel temperature sensor.
3. Inspect for excessive backpressure in the exhaust or blockage at the air filter.
4. Adjust brake pedal switch and cruise cancel switch, especially the clutch switch on manual transmission vehicles.
5. Inspect for custom modifications like sound systems or amps with degraded connections.

Final Fix:

• Fixed the chewed wire at the pump connector.
• After the repair, the car no longer had VDC light issues, no more codes in any module.
• The issue with the fuel cut code in the ABS module and the fuel gauge was resolved.

Common Advice for P0183	Brief Description of Diagnostic Step
Check for proper voltage and ground connections	Verify the voltage at the sensor and ensure good ground connections, as improper voltage can trigger the code.
Inspect wiring and connectors	Look for damaged, loose, or corroded wiring and connectors, especially those leading to and from the sensor.
Test fuel temperature sensor resistance and continuity	Measure the resistance and check for continuity in the fuel temperature sensor to ensure it functions correctly.
Consider possible circuit shorts or open circuits	Investigate the possibility of shorts to power or open circuits in the wiring, which could lead to erroneous sensor readings.
Check for physical damage or interference	Look for any physical damage or interference, such as rodent damage or water ingress, that might affect sensor operation.