P242B - Exhaust Gas Temperature Sensor Circuit Range/Performance Bank 1 Sensor 3
The P242B code indicates that the Engine Control Module (ECM) has detected a performance or range issue with the exhaust gas temperature (EGT) sensor located in Bank 1, Sensor 3 (downstream of the diesel particulate filter or catalytic converter). This sensor monitors exhaust temperature for emissions control and regeneration events. The ECM compares the sensor's signal to expected values; if the signal is out of range or responds too slowly, the code sets. Common causes include a faulty sensor, wiring issues, exhaust leaks, or ECM problems.
01. Most Common Causes
- Faulty exhaust gas temperature sensor
- Damaged or corroded wiring/connector
- Exhaust system leaks near the sensor
- ECM software or hardware issue
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel economy
- Possible limp mode or reduced engine power
- Failed emissions test
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect the EGT sensor and wiring for damage or corrosion.
Step 3: Test sensor resistance and compare to manufacturer specs.
Step 4: Check for exhaust leaks upstream of the sensor.
Step 5: If all else fails, replace the sensor and clear codes.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally safe for short trips, but prolonged driving may cause reduced performance, increased emissions, and potential damage to the DPF or catalytic converter. 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 $150 to $300 at a shop including labor and parts.