Exhaust Gas Temperature Sensor Circuit Low Bank 1 Sensor 3
The P242C code indicates that the exhaust gas temperature (EGT) sensor circuit for Bank 1, Sensor 3 is reading a voltage lower than the expected range. This sensor is typically located downstream in the exhaust system, often after the diesel particulate filter (DPF) or catalytic converter. A low circuit condition can be caused by a faulty sensor, wiring issues (short to ground), or a problem with the engine control module (ECM). This code is common in diesel engines and can affect emissions and regeneration processes.
1. Most Common Causes
- Faulty exhaust gas temperature sensor
- Short to ground in the sensor circuit wiring
- Corroded or damaged connector
- ECM internal failure (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel efficiency
- Possible issues with DPF regeneration
- Increased exhaust emissions
3. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for related codes.
Step 2: Visually inspect the EGT sensor and wiring for damage, corrosion, or loose connections.
Step 3: Measure the sensor resistance and compare to manufacturer specifications (typically 100-200k ohms at room temperature).
Step 4: Check for short to ground by disconnecting the sensor and measuring voltage at the harness connector (should be ~5V reference).
Step 5: If all checks pass, replace the EGT sensor.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally safe for short distances, but prolonged driving may cause incomplete DPF regeneration and potential damage to the exhaust system. It's best to diagnose and repair promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for the sensor part, plus labor if you have a mechanic install it. DIY replacement can save on labor costs.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.