P2067 on Chevrolet: How to Diagnose & Fix

The fifth-generation Camaro carries two fuel level senders in its tank — the pump and primary sender module on one side, a secondary sender on the other, with both signals returning to the PCM. P2067 reports the secondary circuit reading low; GM's criterion is signal voltage below roughly 0.25 V for at least five seconds, where a healthy sender should sit between about 0.5 and 3.5 V and track fuel level. What makes this vehicle worth documenting separately is a specific and expensive dead end: the code can be set by the instrument cluster rather than by anything in the fuel tank, and there is nothing about the code definition that tells you so. In a documented professional diagnosis on a 2013 Camaro ZL1, the fuel gauge dropped to empty and the miles-to-empty function stopped working. The shop replaced both fuel level senders and the fuel pump and verified the sender circuits back to the PCM connector — all of it good. P2067 remained. The clue was in the company the code was keeping: U1804, U0073, U0100 and C0242 were stored alongside it, and when the cluster was commanded through its gauge sweep self-test with a scan tool, the fuel gauge did not sweep. GM's own diagnostic tree ends there — if the fuel level gauge does not sweep during the cluster self-test, the P16 instrument cluster is the failed part. The cluster on these cars is a node on the bus that reads the sender inputs and reports fuel level onward, so an internal failure in the cluster produces the same low secondary fuel level report to the PCM that a shorted sender would. Drivers see the gauge pinned at empty, a low fuel warning that will not go away, a dead or frozen range-to-empty readout in the DIC, and often other cluster oddities, because whatever is wrong inside the cluster is rarely confined to one function.

The C6 Corvette does not use a single fuel tank. Because the rear transaxle and torque tube run down the centerline of the car, the fuel is carried in two connected saddle tanks straddling the driveline, and each tank carries its own level sender. The passenger-side tank holds the fuel pump module and the primary sender (Sensor 'A'); the driver-side tank holds the secondary sender (Sensor 'B'), which is the one P2067 reports on. The secondary sender is a wiper arm riding on a printed resistive card, and it is the resistive card and its contact surface that fail. Two mechanisms are documented by C5/C6 owners. The first is contamination: sulfur and ethanol residue in pump gasoline plate a film onto the contact track, and once the wiper starts skipping across a corroded or scored section of the card the ECM sees the signal collapse toward ground. The second is plain mechanical wear — the wiper cuts a groove into the card at the fuel levels the car spends most of its life at, and once it wears through the circuit reads as a short. Either way the signal voltage on the Sensor 'B' circuit drops below roughly 0.2 V and holds there, and the PCM sets P2067. Owners describe the gauge dropping to empty immediately after a fill-up, a 'Low Fuel' and 'Service Fuel System' message on the DIC, the range-to-empty readout going blank or nonsensical, and a check engine light that returns within a drive cycle or two of being cleared. Because the fault is contact-related rather than a hard open, it is often intermittent at first, appearing at one particular fuel level and then clearing as the float moves past the bad spot on the card, before eventually becoming permanent. Note that the wrong-year replacement sender is a genuine trap here: the resistance range specified for the sender changed during the C6 run, so a brand-new but incorrectly catalogued sender can leave the gauge reading wrong and the code still set. Owners also correlate which tank is at fault with when the gauge misbehaves, since fuel is drawn from the passenger tank first — a fault that appears only in the lower half of the tank points at the driver-side sender.

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.