Fuel Temperature Sensor A Circuit High Input
The P0183 code indicates that the Engine Control Module (ECM) has detected a voltage signal from the fuel temperature sensor (sensor A) that is higher than the expected range. This sensor is typically a thermistor that changes resistance with temperature; a high voltage reading suggests an open circuit, high resistance, or a short to voltage in the sensor or its wiring. The ECM uses this input for fuel delivery and timing adjustments, so an incorrect reading can affect engine performance and emissions.
1. Most Common Causes
- Faulty fuel temperature sensor
- Open or shorted wiring in the sensor circuit
- Poor electrical connection at the sensor or ECM
- Corroded or damaged connector pins
- ECM failure (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Hard starting, especially when hot
- Poor fuel economy
- Rough idle or hesitation
- Black smoke from exhaust (rich mixture)
3. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for related codes (e.g., P0180, P0181).
Step 2: Visually inspect the fuel temperature sensor and its wiring for damage, corrosion, or loose connections.
Step 3: Measure the sensor's resistance with a multimeter; compare to manufacturer specs (typically 200-300 ohms at 68°F).
Step 4: Check for voltage at the sensor connector (should be around 5V reference from ECM).
Step 5: If sensor and wiring are good, test the ECM's ability to read the sensor signal; replace ECM if necessary.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
You can drive short distances, but it may cause poor performance, increased emissions, and potential damage to the catalytic converter if the mixture is too rich. It's best to diagnose and repair promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor. A new fuel temperature sensor costs around $20-$50, and labor is about $30-$100 depending on vehicle accessibility.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.