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 on 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 be caused by wiring issues, connector corrosion, or a failing sensor, leading to incorrect temperature readings and potential drivability or emissions problems.
01. Most Common Causes
- Faulty exhaust gas temperature sensor
- Damaged or corroded wiring/connectors
- Intermittent short or open in the sensor circuit
- ECM software issues (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Possible reduced fuel economy
- May affect diesel particulate filter regeneration
- Possible limp mode or reduced engine power
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for other related codes.
Step 2: Visually inspect the EGT sensor wiring and connector for damage, corrosion, or loose connections.
Step 3: Measure sensor resistance and compare to manufacturer specifications; test for intermittent opens/shorts by wiggling the harness.
Step 4: If wiring is intact, replace the EGT sensor (Bank 1 Sensor 3).
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 incorrect emissions system operation, reduced fuel economy, or 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 replacement of the sensor, or $100 to $300 if professionally diagnosed and repaired, including parts and labor.