P0463 on GMC
Fuel Level Sensor Circuit High Input
P0463 on GMC vehicles indicates fuel level sensor circuit high input. Au7o has documented this code across 2 GMC models — most commonly on Sierra 1500, Sierra 3500HD. This code means the fuel level sensor is reporting a voltage that is higher than the computer expects, which usually translates to a reading suggesting the tank is fuller than possible (such as more than full). The fuel level sensor is the float-and-sender unit inside the fuel tank that tells the gauge and computer how much fuel remains. A high-input signal points to an electrical problem like a short to voltage or an open in the sensor circuit, rather than an actual fuel issue. Besides an inaccurate or pinned fuel gauge, it can disturb EVAP system monitoring that uses fuel level data. Typical repair costs on GMC range from $250 to $1,100, depending on the specific model and root cause.
Common Causes of P0463
- •Faulty fuel level sensor/sending unit (float stuck or worn)
- •Open circuit in the fuel level sensor wiring
- •Short to voltage in the sensor circuit
- •Corroded or loose connector at the tank or sending unit
- •Damaged or stuck float arm inside the tank
- •Faulty instrument cluster or gauge driver
- •Faulty PCM/ECM (rare)
P0463 on GMC by Model
GMC Sierra 1500(1 issue)
- Fuel Level Sensor Failure Causing Erratic or Inoperative Gas Gauge2003-2007
A very common GMT800 complaint is sulfur contamination and wear of the fuel level sensor contacts inside the tank module, causing the gauge to read empty, full, or fluctuate unpredictably. Owners often see a low-fuel warning with plenty of fuel in the tank or watch the gauge drop suddenly while driving. GM issued service information and special coverage on many trucks for this exact condition.
GMC Sierra 3500HD(1 issue)
- Fuel Tank Strap and Fuel Sender Unit Corrosion Causing Fuel Gauge Inaccuracy2007-2014
On 2007–2014 Sierra 3500HD models, the fuel tank mounting straps and the fuel level sender unit are prone to corrosion, causing inaccurate fuel gauge readings and in some cases complete sender failure. NHTSA complaint data documents numerous owners reporting sudden fuel gauge drops to empty or erratic readings unrelated to actual fuel level. The plastic float arm on the sender can also crack, exacerbating the problem.
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View P0463 across all makes →Frequently Asked Questions
What does P0463 mean on GMC?▼
P0463 stands for "Fuel Level Sensor Circuit High Input." This code means the fuel level sensor is reporting a voltage that is higher than the computer expects, which usually translates to a reading suggesting the tank is fuller than possible (such as more than full). The fuel level sensor is the float-and-sender unit inside the fuel tank that tells the gauge and computer how much fuel remains. A high-input signal points to an electrical problem like a short to voltage or an open in the sensor circuit, rather than an actual fuel issue. Besides an inaccurate or pinned fuel gauge, it can disturb EVAP system monitoring that uses fuel level data. On GMC specifically, this code is documented across 2 models.
What causes P0463 on GMC vehicles?▼
Common causes on GMC: Faulty fuel level sensor/sending unit (float stuck or worn), Open circuit in the fuel level sensor wiring, Short to voltage in the sensor circuit, Corroded or loose connector at the tank or sending unit, Damaged or stuck float arm inside the tank. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0463 on a GMC?▼
Repair costs on GMC range from $250 to $1,100, depending on the specific model and root cause.
Which GMC models have P0463 documented?▼
Au7o has documented P0463 on 2 GMC models: Sierra 1500, Sierra 3500HD.