Catalyst Temperature Sensor Circuit High (Bank 1 Sensor 2)
The P042D code indicates that the powertrain control module (PCM) has detected a voltage signal from the catalyst temperature sensor (Bank 1, Sensor 2) that is higher than the expected range. This sensor monitors the temperature of the catalytic converter to ensure efficient operation and protect against overheating. A high circuit condition typically points to a short to voltage, a faulty sensor, or wiring issues. This can lead to inaccurate temperature readings, potentially causing the PCM to misinterpret catalyst efficiency and affect emissions control.
01. Most Common Causes
- Faulty catalyst temperature sensor
- Short to voltage in sensor circuit (wiring or connector)
- Corroded or damaged wiring/connector
- PCM internal failure (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Possible reduced fuel economy
- Potential catalyst overheating (if sensor fails to warn)
- Failed emissions test
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve freeze frame data and confirm the code.
Step 2: Visually inspect the sensor and wiring for damage, corrosion, or loose connections.
Step 3: Measure voltage at the sensor connector with the engine running; compare to manufacturer specifications (typically 0.5-4.5V).
Step 4: If voltage is high (e.g., >4.5V), check for short to power in the signal wire.
Step 5: Test sensor resistance and compare to specs; replace if out of range.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally safe for short distances, but prolonged driving may risk catalytic converter damage due to undetected overheating. It's best to diagnose and repair promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for a DIY sensor replacement, or $100 to $300 if a mechanic performs the repair, including parts and labor.