Exhaust Gas Temperature Sensor Circuit High Bank 1 Sensor 3
The P242D code indicates that the Engine Control Module (ECM) has detected a high voltage signal from the exhaust gas temperature (EGT) sensor located in Bank 1, Sensor 3 (typically downstream of the diesel particulate filter or catalytic converter). This sensor monitors exhaust temperature to protect components and optimize emissions. A high circuit signal suggests a short to voltage, open circuit, or faulty sensor, which can lead to incorrect temperature readings and potential damage to the exhaust aftertreatment system.
1. Most Common Causes
- Faulty exhaust gas temperature sensor
- Short to voltage in sensor wiring or connector
- Open circuit in sensor wiring or connector
- Corrosion or damage at sensor connector
- ECM software or hardware issue (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel economy
- Possible regeneration issues in diesel engines
- Exhaust odor or smoke (if severe)
3. Step-by-Step Diagnosis
Step 1: Scan for additional codes and freeze frame data.
Step 2: Visually inspect the EGT sensor connector and wiring for damage, corrosion, or shorts.
Step 3: Measure sensor resistance and compare to manufacturer specifications (typically 100-200k ohms at room temperature).
Step 4: Check for voltage at sensor signal wire with ignition on; should be around 0.5-4.5V depending on temperature.
Step 5: If sensor and wiring are okay, test ECM output and consider reprogramming or replacement.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally not recommended to drive long distances with this code, as incorrect temperature readings can lead to overheating and damage to the catalytic converter or diesel particulate filter. Short trips to a repair shop are usually okay.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on the vehicle and sensor location. DIY replacement can be cheaper if you have the tools.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.