P019F

What it means

P019F means the engine control unit has judged that the pressure sensor on alternative fuel tank A (for example a CNG or LPG tank, depending on the vehicle) is not performing as expected. The reading may be implausible, stuck, slow to respond, or may disagree with other data such as temperature, fuel use or the pressure after the regulator. The exact test and thresholds depend on the make, model and fuel system.

Symptoms

• Engine warning light on
• Gas or alternative fuel gauge reading incorrectly or erratically
• Car refusing to run on the alternative fuel and staying on petrol
• Hard starting or hesitation when running on the alternative fuel
• Reduced power or poor fuel economy on the alternative fuel
• Unexpected switchover between fuels

Possible causes

• Faulty or drifting tank pressure sensorlikely
• Damaged wiring, corroded or loose connector at the sensorlikely
• Gas leak or restriction in the tank, lines or valve affecting the pressure readingpossible
• Faulty tank shut-off valve or pressure regulator giving a pressure that does not match the sensorpossible
• Low or unstable reference voltage or poor earth to the sensorpossible
• Fault in the alternative fuel control unit or engine control unit, or outdated softwarerare

How to diagnose

1. Read all stored and pending codes and note the freeze frame data, including fuel type in use, tank pressure and temperature.
2. Look for related codes for the sensor circuit, fuel temperature, regulator or fuel system, and deal with those first.
3. Visually inspect the sensor, its wiring and connector for damage, corrosion, moisture, chafing and heat damage.
4. Check for gas leaks around the tank, valve, fittings and lines using the method the manufacturer specifies for the fuel type, and take safety precautions.
5. Compare the live tank pressure reading with the expected value for the tank temperature and fill level, and with a known-good gauge if the procedure allows.
6. Check the sensor supply voltage, earth and signal voltage against the model's wiring diagram, and wiggle-test the harness while watching the live data.
7. Check the operation of the shut-off valve and regulator following the manufacturer's procedure for that system.
8. Check for any software updates or technical bulletins for the vehicle and the alternative fuel system.

How to fix

• Replace the tank pressure sensor if it reads incorrectly or does not respond.
• Repair or replace damaged wiring and clean or renew corroded connectors.
• Repair any gas leaks or restrictions found, using a qualified installer or specialist for the fuel system.
• Replace a faulty shut-off valve or pressure regulator.
• Update the control unit software only where the manufacturer lists it as a fix for this fault, or replace a failed control unit after the other causes are ruled out.

Can I keep driving?

Nearby codes

• P019EGenericAlternative Fuel Tank A Pressure Sensor Circuit
• P01A0GenericAlternative Fuel Tank A Pressure Sensor Circuit Low