Catalyst Temperature Sensor High (Bank 2)
The P0438 code means the vehicle's onboard diagnostic system has detected: Catalyst Temperature Sensor High (Bank 2). This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $80 - $400 (parts and labor)
Reads enhanced codes and shows real-time O2 sensor data. Verify the cat is actually bad before dropping $1,000+ on a replacement.
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What Are the Symptoms of P0438?
- Check Engine Light illuminated
- Scan tool shows abnormally high Bank 2 catalyst temperature
- Possible overheating warning
- No drivability issues in most cases
What Causes P0438? (Most Likely First)
- Faulty Bank 2 catalyst temperature sensor reading high Very High
- Short to voltage in Bank 2 sensor signal wire High
- Open ground wire causing signal to float high Moderate
- Genuine catalyst overheating from Bank 2 misfires Moderate
Can I Still Drive with P0438?
Short distances only. P0438 is rated moderate severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Frequently Asked Questions
Can I drive with code P0438?
Drive short distances only until diagnosed. While a faulty sensor is most likely, if the Bank 2 catalyst is genuinely overheating, continued driving risks a fire or catalyst destruction.
Is P0438 the Bank 2 version of P0428?
Yes. P0428 covers Bank 1 catalyst temperature sensor high and P0438 covers Bank 2. The diagnostic process is identical on the opposite bank.
How do I verify if the catalyst is actually overheating?
Use an infrared thermometer on the Bank 2 exhaust pipe near the converter. If it matches the abnormally high scan tool reading, the overheating is real and likely caused by misfires or a rich condition.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose P0438?
-
Compare scan tool Bank 2 catalyst temperature to an infrared thermometer measurement
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Check if the reading is plausible -- readings above 1800 degrees F likely indicate a sensor fault
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Verify Bank 2 sensor ground wire continuity
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Check signal wire for short to voltage
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If readings appear accurate, check for Bank 2 misfires or rich fuel condition
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Which Vehicles Commonly Get P0438?
- 2005-2017 Toyota Tundra V8
- 2006-2018 Lexus IS 350
- 2004-2016 Nissan Titan
- 2003-2015 Subaru Outback H6
- 2007-2019 Toyota Sequoia
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