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 is saying that a sensor, which checks how hot the exhaust is, is giving a reading that's too high. It's like a thermometer that's saying it's way hotter than it should be.
The P0428 code indicates that the vehicle's Engine Control Module (ECM) has detected a high voltage signal from the catalyst temperature sensor on Bank 1, Sensor 1.
The catalyst temperature sensor measures the temperature of the catalytic converter to ensure it operates efficiently. When the ECM detects a voltage signal that is higher than the expected range, it triggers the P0428 code. This could be due to a short circuit, a faulty sensor, or an issue with the ECM itself.
• Check Engine Light is on
• Possible decrease in engine performance
• Increased emissions
• Faulty catalyst temperature sensor
• Wiring issues such as shorts or open circuits
• Faulty Engine Control Module (ECM)
ECM: Engine Control Module
Catalytic Converter: A device that reduces harmful emissions from the engine
• Use an OBD-II scanner to confirm the code
• Inspect the wiring and connectors for damage
• Test the catalyst temperature sensor for proper operation
• Replace the catalyst temperature sensor
• Repair or replace damaged wiring or connectors
• Reprogram or replace the ECM if necessary
• OBD-II scanner
• Digital multimeter
• Basic hand tools
$150 - $400
Moderate
• Toyota Camry
• Honda Accord
• Ford F-150
• Regularly inspect and maintain the exhaust system
• Ensure proper engine tuning and maintenance
• Avoid using low-quality fuel
Sensor Issue
• Have the vehicle inspected by a professional mechanic
• Avoid driving the vehicle for long distances until the issue is fixed
Check with the vehicle manufacturer for warranty coverage on emissions-related components.
The P0428 code has been a common issue in vehicles with advanced emissions systems, particularly as they age.
Moderate – It's important to address this issue to prevent potential damage to the catalytic converter and ensure emissions compliance.
Ignoring emissions-related codes may lead to failing emissions tests and potential fines.
• Engine at operating temperature
• Vehicle running at idle
The catalyst temperature sensor is located near the catalytic converter on the exhaust system, typically on the side of the engine labeled as Bank 1.
Q: Can I drive with a P0428 code?
A: It's not recommended to drive for extended periods with this code, as it could lead to further damage.
Q: How do I reset the P0428 code?
A: After fixing the issue, you can use an OBD-II scanner to clear the code.
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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.
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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.
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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.