P0462 on 2020-2021 Chevrolet Corvette: Fuel Level Sensor Circuit Low Causes and Fixes

What's Unique About the 2020-2021 Chevrolet CORVETTE

The 2020-2021 C8 Corvette was an all-new, mid-engine platform. Early production models were susceptible to a specific fuel sender issue, prompting General Motors to issue a technical service bulletin (TSB #20-NA-042). The problem is almost exclusively with the left-side fuel level sensor, causing erratic gauge behavior. The C8 uses a dual-tank system to accommodate the mid-engine layout, and Sensor 1 corresponds to the left tank. Unlike older cars where wiring corrosion or fuel additives might be common culprits, the issue on these specific first-year and second-year Corvettes is very frequently a premature failure of the sensor component itself.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Fuel gauge intermittently displays erratic readings (e.g., jumping between full and empty).
• Fuel gauge stuck on empty.
• Check Engine Light (Malfunction Indicator Lamp or MIL) is on.
• Distance to Empty or Range display shows "---" or an inaccurate number.

Most Likely Causes

1. Faulty Left Fuel Tank Level Sensor 🔴 High Probability A known issue on 2020-2021 models, as documented in GM TSB #20-NA-042, points to premature failure of this specific component due to erratic fuel value readings.
   How to confirm: A technician will use a diagnostic scan tool to monitor the live data for "Fuel Level Sensor 1". If the voltage is consistently below the specified threshold (e.g., under 0.5V), the sensor is faulty. On a similar GM system, a fault is typically registered if the sensor voltage remains below 0.39V for more than 50 seconds. A diagnostic test of the sensor's resistance should show a range between approximately 40Ω (empty) and 250Ω (full).
   Typical fix: Replace the left side fuel tank level sensor kit as per the procedure in TSB #20-NA-042.
   Est. part cost: $100-$200
2. Wiring or Connector Issue ⚪ Low Probability While possible on any vehicle, this is a very low probability cause for this specific code on the 2020-2021 Corvette compared to the known sensor failure. Issues are more likely on modified cars where the fuel system has been disassembled, potentially pinching a wire or causing a bad connection.
   How to confirm: Inspect the wiring harness leading to the fuel tank for any signs of damage, chafing, or corrosion. A technician would perform a continuity and short-to-ground test on the sensor's signal circuit.
   Typical fix: Repair the damaged section of the wiring harness or clean/replace the affected connector.
   Est. part cost: $5-$50

Rare But Worth Checking

• Powertrain Control Module (PCM) Malfunction: This is extremely rare. Before condemning the PCM, all other possibilities, especially the sensor and its wiring, must be exhaustively ruled out.

Diagnosis Steps

1. Verify the Check Engine Light is on and use an OBD-II scanner to confirm P0462 is the active code.
🎬 Watch: Understanding the causes and fixes for the P0462 code
2. Check for GM Technical Service Bulletin #20-NA-042, as it directly addresses this code for this vehicle and was updated for the 2021 model year on May 5, 2021.
3. Using a professional scan tool, access the live data stream for the fuel system and monitor the voltage from "Fuel Level Sensor 1".
4. Observe if the voltage is below the normal range (typically <0.5V, with a fault often set below 0.39V).
5. If the sensor voltage is abnormal, check fuse #22 in the rear compartment fuse block, which powers the Fuel Pump/Fuel Tank Zone Module.
6. If the fuse is intact and accessible, test the sensor's resistance. It should sweep smoothly between ~40Ω and ~250Ω. An open or shorted reading indicates a failed sensor.
7. If wiring is suspected, perform a continuity test on the signal and ground wires between the ECM and the fuel level sensor.
8. If wiring and fuse are confirmed to be good, the fault lies with the fuel level sensor itself.
9. Replace the left-side fuel level sensor assembly following the service procedure outlined by GM.

Parts You'll Likely Need

• Fuel Level Sensor Kit (OEM #84745186) — This is the causal part identified by GM in TSB #20-NA-042 to fix the erratic fuel gauge and P0462 code. It is officially described as 'SENSOR KIT, FUEL LVL'.
  Trusted brands: ACDelco (GM Genuine Parts)
  OEM price range: $130-$200
  Aftermarket price range: $100-$150

Technical Service Bulletins (TSBs) & Recalls

• 20-NA-042: Fuel Gauge May Intermittently Display Erratic and/or Empty Readings, Malfunction Indicator Lamp (MIL) Illuminated - DTC P0462 Set. This TSB confirms the cause is the left fuel tank level sensor and provides the part number (84745186) and labor operation (4087408, 4.5 hrs) for the fix.

Platform-Specific Known Issues

• A significant number of 2020-2021 Corvettes were affected by a faulty left fuel tank level sensor, leading GM to issue TSB #20-NA-042. This bulletin provides a specific service procedure to replace the sensor and correct the condition.
• The TSB was initially released in March 2020 and later updated in October 2020 and May 2021 to include the 2021 model year.

Mechanic-Grade Diagnostic Values

• Fuel Level Sensor Resistance — expected: Approximately 40Ω (±1Ω) when the tank is empty and 250Ω (±2.4Ω) when the tank is full. The reading should sweep smoothly between these values.. Failure: A reading of infinite resistance (open circuit) or zero resistance (short circuit), or readings that jump erratically.
• Fuel Level Sensor 1 Signal Voltage (at ECM) — expected: Varies with fuel level, typically between ~1.0V (empty) and ~2.5V (full).. Failure: A sustained voltage reading below 0.39V for more than 50 seconds will trigger a fault code.

Wiring & Ground Locations

• Fuse F22 — In the rear compartment fuse block.. This MINI-type fuse supplies power to the 'Fuel pump/Fuel tank zone module'. A blown fuse would cut power to the module responsible for processing the fuel level sensor signal, potentially causing a low voltage code.

Real Owner Repair Stories

• Carly community author (2018 Chevrolet Corvette) — Check engine light on, stalling at idle, and a fuel level sensor related error code.
  ❌ Tried (didn't work) Visual inspection of wiring.
  ✅ What actually fixed it The fuse for the fuel level sensor circuit was blown. Replacing the fuse resolved all symptoms.

OEM Part Supersession History

• 84745186 → 84745186 (no change) — The part number for the replacement Fuel Level Sensor Kit remained consistent across multiple revisions of TSB 20-NA-042 from March 2020 to May 2021.
  Heads up: No supersession noted. The same part was used for the repair throughout the 2020-2021 period.