The P0185 OBD2 fault code indicates that the engine control module (ECM/PCM) has detected a problem with the Fuel Temperature Sensor B circuit. This sensor provides fuel temperature information to the engine management system, helping the computer adjust fuel-related calculations. The exact sensor location and circuit design can vary depending on the vehicle make, model, engine, and fuel system.
Fault Code Description
Code: P0185
Definition: Fuel Temperature Sensor "B" Circuit
Type: Generic OBD2 Trouble Code
System: Fuel and Engine Management
P0185 is a generic OBD2 powertrain code. It can appear on vehicles from many manufacturers, but the sensor location, wiring, connector configuration, and diagnostic procedure are not necessarily the same between brands.
Symptoms of P0185
- Check Engine Light is illuminated.
- Hard or extended engine starting.
- Rough or unstable idle.
- Engine hesitation during acceleration.
- Reduced engine performance.
- Increased fuel consumption.
- Incorrect fuel temperature readings in live data.
- In some vehicles, there may be no noticeable drivability symptoms.
Common Causes of P0185
- Faulty Fuel Temperature Sensor B.
- Damaged or broken sensor wiring.
- Open or short circuit in the sensor circuit.
- Loose or damaged electrical connector.
- Corroded sensor terminals.
- Poor sensor ground or reference circuit.
- Wiring damaged by heat, vibration, or friction.
- ECM/PCM fault in rare cases.
P0185 on Nissan and Chevrolet Vehicles
The P0185 code can be found on different vehicle brands, including Nissan and Chevrolet, but the actual implementation of Fuel Temperature Sensor B can differ between models and engines.
Nissan
On some Nissan applications, fuel temperature information may be integrated into a larger fuel-system component rather than using a simple standalone sensor. Therefore, the correct Nissan wiring diagram and service information should be checked before replacing a component.
Chevrolet
On some Chevrolet applications, the fuel temperature sensor circuit may be associated with the fuel delivery system or another fuel-system assembly. The exact sensor location and circuit configuration depend on the specific Chevrolet model and engine.
These are examples only. The presence of P0185 on Nissan or Chevrolet does not mean that every model uses the same sensor location or wiring configuration.
P0185 Severity
Severity: Moderate. P0185 should be diagnosed promptly because incorrect fuel temperature information can affect engine management and fuel-related calculations.
Some vehicles may continue to drive normally with P0185, while others may experience starting difficulties, hesitation, poor fuel economy, or reduced performance.
Average Repair Cost
The repair cost for P0185 depends on the vehicle and the actual cause of the circuit fault. Typical estimated costs include:
- Diagnostic testing: $50–$150
- Fuel temperature sensor replacement: $100–$300
- Wiring repair: $80–$250
- Connector repair or replacement: $80–$200
- ECM/PCM repair or replacement: $500–$1,500+
These are general estimates only. Actual costs vary according to the vehicle make and model, labor rates, parts availability, and sensor location.
How to Diagnose P0185
1. Scan for Trouble Codes
Connect an OBD2 scanner and check for P0185 along with any stored or pending trouble codes. Additional fuel-system codes may provide useful diagnostic information.
2. Check Fuel Temperature Live Data
Monitor the Fuel Temperature Sensor B reading using a scan tool. Compare the displayed temperature with the actual fuel temperature and surrounding conditions.
3. Inspect the Sensor Connector
Inspect the connector for corrosion, loose terminals, damaged pins, moisture, or poor electrical contact.
4. Inspect the Wiring
Check the harness for broken wires, damaged insulation, chafing, heat damage, and previous repairs that may have created a poor connection.
5. Test the Sensor Circuit
Using the correct manufacturer wiring diagram, test the sensor power or reference circuit, ground, and signal circuit. Do not assume the pin configuration is identical between Nissan, Chevrolet, Ford, or other manufacturers.
6. Test Fuel Temperature Sensor B
Test the sensor according to the manufacturer's specifications. If the sensor resistance or signal does not correspond to the specified fuel temperature, the sensor may be defective.
7. Clear the Code and Retest
After repairing the confirmed problem, clear the code and perform a road test. Recheck the live data and verify that P0185 does not return.
Common Repairs for P0185
- Replace the faulty Fuel Temperature Sensor B.
- Repair damaged or broken wiring.
- Repair an open or short circuit.
- Clean or replace corroded connector terminals.
- Repair the sensor ground or reference circuit.
- Secure the wiring away from excessive heat and vibration.
- Repair or replace the ECM/PCM only after confirming the sensor and wiring are good.
Common Diagnostic Mistakes
- Replacing the sensor without testing the circuit.
- Assuming P0185 always means the sensor is defective.
- Ignoring damaged or corroded connectors.
- Using the wrong wiring diagram for the vehicle.
- Assuming Nissan and Chevrolet use the same sensor configuration.
- Replacing the ECM/PCM before proving it is faulty.
- Ignoring additional stored trouble codes.
- Clearing the code without repairing the underlying problem.
Can You Drive With P0185?
The vehicle may remain drivable if it starts and operates normally, but P0185 should be diagnosed as soon as possible. An incorrect fuel temperature signal can affect engine operation and fuel economy.
If the vehicle develops severe hesitation, stalling, major starting problems, or significant loss of power, it should be inspected before continued driving.
Related OBD2 Codes
- P0180 – Fuel Temperature Sensor "A" Circuit
- P0181 – Fuel Temperature Sensor "A" Circuit Range/Performance
- P0182 – Fuel Temperature Sensor "A" Circuit Low
- P0183 – Fuel Temperature Sensor "A" Circuit High
- P0184 – Fuel Temperature Sensor "A" Circuit Intermittent
- P0185 – Fuel Temperature Sensor "B" Circuit
- P0186 – Fuel Temperature Sensor "B" Circuit Range/Performance
- P0187 – Fuel Temperature Sensor "B" Circuit Low
- P0188 – Fuel Temperature Sensor "B" Circuit High
- P0189 – Fuel Temperature Sensor "B" Circuit Intermittent
FAQ
What does the engine code P0185 mean?
P0185 means the ECM/PCM has detected a fault in the electrical circuit of Fuel Temperature Sensor B. The fault may involve the sensor, wiring, connector, ground, reference circuit, or another electrical component.
Is P0185 a generic OBD2 code?
Yes. P0185 is a generic OBD2 powertrain code. However, the exact sensor location and circuit design can vary between vehicle manufacturers and models.
Does P0185 mean the fuel temperature sensor is bad?
Not necessarily. The sensor should be tested along with its wiring, connector, power or reference circuit, and ground before replacement.
Can P0185 cause poor fuel economy?
Yes. An incorrect fuel temperature signal can affect engine-management calculations and may contribute to increased fuel consumption.
Can Nissan vehicles have P0185?
Yes. P0185 can occur on Nissan vehicles, but the exact sensor location and circuit configuration depend on the specific Nissan model and engine.
Can Chevrolet vehicles have P0185?
Yes. Chevrolet is another example of a manufacturer where P0185 may occur. The correct diagnostic procedure should be based on the specific Chevrolet model and engine.
How do I fix P0185?
The correct repair depends on the diagnosis. Common repairs include replacing the Fuel Temperature Sensor B, repairing wiring or connectors, and correcting a ground, reference, open, or short circuit.
Is P0185 serious?
P0185 is generally considered a moderate-severity fault. It may not cause immediate engine damage, but it should be diagnosed because it can affect engine operation and fuel management.
Conclusion
The P0185 OBD2 fault code indicates a problem with the Fuel Temperature Sensor B circuit. The cause may be a defective sensor, damaged wiring, connector problems, an open or short circuit, or another electrical fault. Although Nissan and Chevrolet are examples of manufacturers where this code can be encountered, the actual sensor location and circuit design vary by vehicle. Always use the correct manufacturer-specific wiring diagram and specifications when diagnosing P0185.