Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
The car's computer isn't getting any signals from one of the oxygen sensors, which helps the car know how much fuel to use.
The P0140 code indicates that the oxygen sensor located after the catalytic converter on bank 1 is not sending any signals to the engine control module (ECM).
The oxygen sensor (O2 sensor) measures the amount of oxygen in the exhaust gases. Bank 1 Sensor 2 is the sensor located after the catalytic converter on the side of the engine with cylinder 1. If the ECM detects no activity from this sensor, it triggers the P0140 code.
• Check Engine Light is on
• Increased fuel consumption
• Failed emissions test
• Faulty oxygen sensor
• Wiring issues or poor connections
• Exhaust leaks
• Faulty ECM
ECM: Engine Control Module
OBD-II: On-Board Diagnostics II
O2 Sensor: Oxygen Sensor
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connections for damage.
• Check for exhaust leaks near the sensor.
• Test the oxygen sensor with a multimeter.
• Replace the faulty oxygen sensor.
• Repair or replace damaged wiring.
• Fix any exhaust leaks.
• Update or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Wrench set
$150 - $300
Moderate
• Toyota Camry
• Honda Accord
• Ford F-150
• Regularly inspect and maintain the exhaust system.
• Perform routine checks on sensor connections.
• Use high-quality fuel to prevent sensor contamination.
Sensor Issue
• Address the issue promptly to avoid increased fuel consumption.
• Consult a professional if unsure about the repair process.
Check your vehicle's warranty for coverage on emissions-related components.
The P0140 code has been a common issue since the introduction of OBD-II systems, often related to sensor wear or wiring issues.
Moderate – While the car may still run, it can lead to increased emissions and fuel consumption.
Driving with a faulty sensor can lead to failed emissions tests and potential fines in areas with strict emissions regulations.
• Engine at operating temperature
• Vehicle running at idle
The oxygen sensor is located on the exhaust pipe after the catalytic converter on the same side as cylinder 1.
Q: Can I drive my car with a P0140 code?
A: Yes, but it's not recommended as it can lead to increased emissions and fuel consumption.
Q: How can I prevent oxygen sensor issues?
A: Regular maintenance and using quality fuel can help prevent sensor issues.
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.
Fitment Required · Vehicle-fitment part
Relevant when the code or supporting diagnostics point toward upstream or downstream oxygen-sensor faults.
This code family often involves upstream or downstream oxygen-sensor diagnosis.
Verify exact sensor position and vehicle fitment before buying.
View options on Amazon
Fitment Required · Vehicle-fitment part
Relevant when catalyst-efficiency or emissions faults persist after proper diagnosis.
Catalyst-efficiency faults sometimes point toward converter problems after proper testing.
Catalytic converters are highly vehicle-specific and should not be purchased by code alone.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.