Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer is having trouble talking to the sensor that checks the pressure or temperature in the fuel tank. It's like when you can't hear your friend on the phone because the line is cut.
The P1231 code indicates a problem with the electrical circuit of the fuel tank pressure or temperature sensor, which could be due to an open circuit.
The P1231 code is triggered when the Engine Control Module (ECM) detects an open circuit or a malfunction in the fuel tank pressure or temperature sensor circuit. This sensor is crucial for monitoring the pressure or temperature within the fuel tank to ensure optimal fuel system performance and emissions control.
• Check Engine Light is on
• Possible fuel odor
• Decreased fuel efficiency
• Difficulty starting the engine
• Faulty fuel tank pressure/temperature sensor
• Open or shorted wiring in the sensor circuit
• Poor electrical connection at the sensor
• Faulty ECM
ECM: Engine Control Module
OBD-II: On-Board Diagnostics, a standardized system in vehicles for self-diagnosing and reporting
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for damage.
• Test the fuel tank pressure/temperature sensor for proper operation.
• Check the ECM for any faults.
• Repair or replace damaged wiring or connectors.
• Replace the faulty sensor.
• Update or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Wrench set
$150 - $400
Moderate
• Ford F-150
• Chevrolet Silverado
• Toyota Camry
• Regularly inspect and maintain the fuel system.
• Ensure proper electrical connections.
• Use quality fuel to prevent sensor contamination.
Sensor Issue
• Address this issue promptly to avoid further damage.
• Consult a professional mechanic if unsure about the repair.
Check your vehicle's warranty for coverage on emissions-related components.
The P1231 code has been associated with issues in vehicles with advanced fuel system monitoring, particularly in models from the early 2000s.
Moderate – While not immediately dangerous, it can affect fuel efficiency and emissions.
Driving with a malfunctioning fuel system can lead to increased emissions and may not comply with local environmental regulations.
• Vehicle at operating temperature
• Fuel tank at least half full
The fuel tank pressure/temperature sensor is typically located on or near the fuel tank.
Q: Can I drive my car with a P1231 code?
A: While the car may still run, it's best to fix the issue to avoid potential fuel efficiency loss and increased emissions.
Q: How can I reset the Check Engine Light?
A: After fixing the issue, you can use an OBD-II scanner to clear the code and reset the light.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
Network faults often require full-system access instead of a generic code reader alone.
View on Amazon
Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
View on Amazon
Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.