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DTC codes / P01xx · Fuel and air metering / P019F

P019FAlternative Fuel Tank A Pressure Sensor Performance

P019F indicates that the powertrain control module (PCM) has detected a performance problem with the pressure sensor circuit for the alternative fuel tank, designated as Tank A. The PCM monitors the sensor's signal for rationality, range, and response time, and sets this code when the signal does not behave as expected under known operating conditions.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering

Symptoms you may notice

  • Illumination of the malfunction indicator lamp (MIL) on the dashboard
  • Often no symptoms besides the warning light
  • Rough running or hesitation if the vehicle is operating on the alternative fuel
  • Difficulty starting when running on the alternative fuel
  • Reduced power or limp-home mode in some vehicles
  • Fuel gauge or range display inaccuracies for the alternative fuel system

Common causes, most likely first

  1. Faulty alternative fuel tank pressure sensor
  2. Damaged or corroded wiring or connector at the sensor
  3. Open or short circuit in the sensor signal or reference voltage circuit
  4. Poor ground connection for the sensor
  5. Mechanical issue with the tank pressure sensor port or mounting
  6. PCM software or internal fault (less common)

How to diagnose and fix it

  1. Connect a scan tool and record freeze-frame data and any related codes to understand the conditions when the fault set
  2. Visually inspect the sensor, connector, and wiring for damage, corrosion, or loose pins
  3. Check reference voltage and ground at the sensor connector with a multimeter
  4. Backprobe the sensor signal wire and compare voltage to the manufacturer's specification while monitoring live data
  5. Perform a wiggle test on the harness while watching sensor data to detect intermittent faults
  6. If the sensor signal is out of range, replace the sensor and clear codes to verify the repair
  7. If wiring is faulty, repair or replace the affected section of the harness and retest

What P019F really tells you about tank pressure

  • This code often sets without any drivability symptoms because the alternative fuel system may not be in active use, so the driver notices only the warning light.
  • A common misdiagnosis is replacing the sensor when the actual problem is a chafed wire or corroded connector that only acts up under vibration or temperature changes.
  • The PCM may set P019F due to a rationality check that compares the tank pressure sensor signal to other sensors, so a fault in a related sensor can trigger this code.
  • On some vehicles, the alternative fuel tank pressure sensor is part of a larger assembly, and a failure in that assembly can cause this code along with others.
  • Always check for technical service bulletins (TSBs) for the specific vehicle, as some manufacturers have known issues with sensor calibration or software.

Can I keep driving with P019F?

If the vehicle runs normally on gasoline, you can drive it to a repair shop, but avoid using the alternative fuel until the fault is diagnosed. If drivability issues are present, limit driving and seek professional diagnosis promptly.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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