Catalyst Temperature Sensor Circuit Bank 1 High (Generic)
The P4018 code means the vehicle's onboard diagnostic system has detected: Catalyst Temperature Sensor Circuit Bank 1 High (Generic). This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $100 - $400 (parts and labor)
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Common Symptoms
- Check Engine Light on
- False high catalyst temperature reading
- Engine power limited to protect catalyst
- Poor performance under load
Probable Causes (Ranked by Likelihood)
- Short to voltage in sensor circuit Very High
- Sensor internal failure reading high High
- Chafed wiring near exhaust Moderate
- PCM reference voltage fault Low
Step-by-Step Diagnostic Procedure
-
Check sensor voltage with key on engine off
-
Disconnect sensor and test for voltage on signal wire
-
Inspect wiring for damage near hot components
-
Verify 5V reference circuit integrity
Frequently Asked Questions
Will false high reading damage my engine?
No, but the PCM may severely limit engine power to protect the catalytic converter from what it perceives as dangerous overheating.
Can I drive with P4018?
You can drive short distances but performance will be significantly reduced. The engine may feel sluggish especially under load.
What causes the sensor to read high?
Usually a short to voltage in the wiring where insulation has been damaged by exhaust heat, or an internal sensor failure.
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