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 thinks the temperature sensor for the exhaust system on one side of the engine is reading too high.
The P0438 code indicates that the temperature sensor for the catalytic converter on bank 2, sensor 1, is reporting a voltage that is higher than expected.
The P0438 code is triggered when the Powertrain Control Module (PCM) detects a voltage signal from the catalyst temperature sensor that is higher than the specified range. This sensor is responsible for monitoring the temperature of the catalytic converter to ensure it is operating efficiently.
• Check Engine Light is on
• Poor fuel economy
• Possible decrease in engine performance
• Faulty catalyst temperature sensor
• Wiring issues such as short circuits or open circuits
• Faulty PCM
PCM: Powertrain Control Module
OBD-II: On-Board Diagnostics, Second Generation
• Use an OBD-II scanner to verify the code.
• Inspect the wiring and connectors for damage or corrosion.
• Test the catalyst temperature sensor for proper operation.
• Replace the catalyst temperature sensor if faulty.
• Repair or replace damaged wiring or connectors.
• Reprogram or replace the PCM if necessary.
• OBD-II scanner
• 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 driving with a malfunctioning engine.
Sensor Issue
• Address the issue promptly to avoid further damage.
• Consult a professional mechanic if unsure about the repair.
Check with the vehicle manufacturer for specific warranty coverage on emissions-related components.
This code has been associated with issues in vehicles that have aging catalytic converters or sensors.
Moderate – It is advisable to address this issue soon to prevent potential damage to the catalytic converter.
Driving with a malfunctioning catalytic converter can lead to increased emissions and may not comply with local emissions regulations.
• Engine at operating temperature
• Vehicle in closed-loop mode
The catalyst temperature sensor is located near the catalytic converter on the exhaust system of bank 2.
Q: What does Bank 2 mean?
A: Bank 2 refers to the side of the engine that does not contain cylinder 1.
Q: Can I drive with a P0438 code?
A: It's not recommended to drive for extended periods with this code, as it may lead to further damage.
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Universal · Digital multimeter
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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.