P2066 on Chevrolet: How to Diagnose & Fix
Fuel Level Sensor "B" Circuit Range/Performance
2 Chevrolet models · 2 documented issues · $350-$1,400 repair
P2066 on Chevrolet by model: symptoms, diagnosis and fix
The C6 Corvette carries its fuel in two saddle-shaped tanks that straddle the driveline tunnel, each with its own level sender. The left tank holds the fuel pump module and its sender is Fuel Level Sensor 'A'; the right tank has a passive sender, Fuel Level Sensor 'B', and its fuel is siphoned across to the pump side. Because the right tank is drawn down first, the 'B' float and its resistor card spend much of the car's life sitting in vapor rather than submerged in gasoline, and owners report the code appearing most often when the car is driven hard on less than half a tank. That dry-wiping is what kills them: the wiper arm scrubs a dead spot or a high-resistance band into the resistive card, so the sender's output stops tracking fuel actually being burned. The PCM compares the two senders and the fuel actually consumed, and when the 'B' signal is present but not credible it sets P2066 rather than a hard open/short code such as P2067 or P2068. Owners typically describe a gauge that reads correctly on a fresh fill, then hangs at a fixed value for many miles before dropping abruptly, a Driver Information Center range-to-empty figure that goes nonsensical, and in some cases a gauge the cluster disables outright. The condition is not mechanically dangerous, but it strands owners who trust the gauge, and a stored MIL will block emissions readiness. Note that P2066 on this platform can also be provoked by a weak siphon jet pump that leaves the right tank unequally full, so the fuel level of both sides should be compared before condemning the sender.
Common Symptoms
- Check engine light with P2066 stored
- Fuel gauge sticks at one reading then drops suddenly
- Inaccurate or erratic fuel gauge
- Distance-to-empty in the DIC reads implausibly
- Code sets after hard driving on less than half a tank
- Code returns days or weeks after being cleared
How to Fix
Start with data, not parts. With a scan tool, watch the Fuel Level Sensor A and Fuel Level Sensor B values while the car burns down a tank: a healthy sender sweeps smoothly, while a worn card either freezes at one value or jumps in steps. Back-probe the right sender connector and check the sender's resistance through its float travel; that also separates a bad sender from a corroded connector or a chafed harness where it passes over the tank saddle, both of which mimic the same fault. If the 'B' side reads full while 'A' drains fast, suspect the siphon jet pump rather than the sender. The accepted repair for a worn card is replacement of the right-hand fuel level sensor kit; the right and left senders are physically different and are not interchangeable, and the passenger-side kit is GM/ACDelco 19420830 (supersedes 19207711/19149683). Access requires lowering the rear of the exhaust and dropping or lowering the right tank, which is why labor dominates the bill. Replace the sender's seal at the same time, keep the tank as empty as practical before the drop, and clear codes and drive at least two full fuel-burn cycles before declaring the repair good, since the rationality monitor needs substantial fuel consumption to re-run. Owners also report that refilling at the half-tank mark keeps the right-side sender bathed in fuel and slows the wear.
Sources for this issue (4)
The in-tank fuel-level sender's resistive card wears, causing the fuel gauge to read inaccurately — stuck on Empty or Full, bouncing/fluctuating, or dropping to E with a false low-fuel warning. The sender is integral to the fuel pump module, so a worn card typically means dropping the tank. It is a well-known GM truck problem; on high-mileage trucks technicians recommend replacing the complete fuel pump module rather than just the sender.
Common Symptoms
- Fuel gauge stuck on E or F
- Gauge needle bounces/fluctuates
- False low-fuel warning light
- Gauge reads wrong after fill-up
How to Fix
First rule out a blown fuel-gauge/sender fuse and attempt a scan-tool sensor recalibration. If the gauge is still erratic, replace the fuel level sending unit — on high-mileage trucks replace the complete in-tank fuel pump module (ACDelco/Delphi module) since the pump often follows. Requires dropping the fuel tank.
Sources for this issue (1)
P2066 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P2066 mean on a Chevrolet?
P2066 stands for "Fuel Level Sensor "B" Circuit Range/Performance." Set when the Fuel Level Sensor 'B' signal is present but implausible or does not track expected fuel usage compared with the primary sender, indicating a performance problem rather than a hard open/short. On Chevrolet it is documented across 2 models: Corvette, Tahoe.
What are the most common causes of P2066?
The most common causes of P2066 are: Worn or sticking fuel level sender float/rheostat, High-resistance wiring or ground, Debris/contamination affecting the float, Faulty fuel level sensor 'B', PCM/ECM fault (rare). The specific cause varies by vehicle.
How much does it cost to fix P2066 on a Chevrolet?
Published repair estimates on Chevrolet range from $350 to $1,400 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P2066 on a different make?
View P2066 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.