P242E: Exhaust Gas Temperature Sensor Circuit Intermittent/Erratic Bank 1 Sensor 3
The P242E code indicates that the Engine Control Module (ECM) has detected an intermittent or erratic signal from the exhaust gas temperature (EGT) sensor located at Bank 1, Sensor 3 (typically downstream of the diesel particulate filter or catalytic converter). This sensor monitors exhaust temperature for emissions control and regeneration events. An intermittent signal can cause incorrect temperature readings, leading to improper regeneration or emissions system operation.
1. Most Common Causes
- Faulty EGT sensor (Bank 1 Sensor 3)
- Damaged or corroded wiring/connector to the sensor
- Exhaust system leaks near the sensor
- ECM software issues or intermittent electrical interference
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel economy
- Possible limp mode or reduced engine power
- Failed emissions test
3. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for additional codes.
Step 2: Visually inspect the EGT sensor and its wiring for damage, corrosion, or loose connections.
Step 3: Test the sensor's resistance and voltage output with a multimeter and compare to manufacturer specifications.
Step 4: Check for exhaust leaks near the sensor that could cause erratic readings.
Step 5: If no issues found, clear the code and test drive to see if it returns; if it does, replace the sensor.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally safe for short trips, but prolonged driving may cause incomplete regeneration, leading to clogged DPF or catalytic converter damage. It's best to diagnose and fix 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.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.