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P2026 — Evap Fuel Vapor Temperature Sensor Circuit Low Voltage

Manufacturer-specificPowertrain (engine & transmission)

P2026 indicates a low voltage condition in the Evaporative Fuel Vapor Temperature Sensor circuit. The powertrain control module has detected that the sensor signal is below the expected range, suggesting an issue with the sensor, wiring, or related components.

Symptoms

What causes it — most likely first

1. Faulty EVAP fuel vapor temperature sensor

The sensor itself may have failed or become internally shorted, producing a low voltage signal.

2. Corroded, damaged, or disconnected wiring or connectors

Broken wires, poor connector contacts, or corrosion can cause a drop in voltage reaching the PCM.

3. High resistance in the sensor circuit (e.g., due to a bad ground)

A poor ground or high‑resistance path can limit voltage and trigger the low‑voltage condition.

4. Faulty power supply to the sensor (e.g., blown fuse or relay problem)

If the sensor is not receiving proper reference voltage, the PCM will read low voltage.

5. PCM internal fault (rare)

A malfunction inside the powertrain control module can misinterpret a normal sensor signal as low voltage, but this is uncommon.

How it's diagnosed

  1. Verify the Check Engine Light code and clear it to see if it returns.
  2. Inspect the sensor wiring harness for cracks, chafing, corrosion, or loose connectors; repair as needed.
  3. Measure sensor voltage at the connector with the ignition on; compare to manufacturer specifications (typically around 5 V).
  4. Test continuity and resistance of the sensor circuit to ground and power; replace the sensor if readings are out of spec.
  5. Check related fuses and relays supplying power to the sensor circuit and replace any that are faulty.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationManufacturer-specific (P1/B1/C1/U1)
Related codesP2020 — Intake Manifold Runner Position SensorP2021 — Intake Manifold Runner Position SensorP2022 — Intake Manifold Runner Position SensorP2023 — Intake Manifold Runner Position SensorP2024 — Evap Fuel Vapor Temperature Sensor CirP2025 — Evap Fuel Vapor Temperature Sensor Per

Frequently asked

Do I need to replace the PCM to fix P2026?

No. In the overwhelming majority of cases the problem is the sensor, wiring, or power supply. PCM replacement is only considered after all other possibilities have been ruled out and is extremely rare.

Can a bad fuel cap cause P2026?

A loose or damaged fuel cap can trigger other EVAP codes, but it does not affect the temperature sensor circuit voltage, so it is not a cause for P2026.

Will fixing P2026 improve fuel economy?

If the underlying issue is a leak or sensor malfunction that forces the system into a fail‑safe mode, correcting it can restore normal fuel‑trim operation and may improve mileage.

Is it safe to drive with this code set?

The vehicle will generally run, but the EVAP system may be disabled, leading to higher emissions and possible failure of an emissions inspection. Repair is recommended.