Code P242C: Causes, Symptoms, and Solutions
Code P242C is an OBD-II diagnostic trouble code related to the Exhaust Gas Temperature Sensor (EGTS) circuit. It indicates a performance range or signal out of specification issue for the Exhaust Gas Temperature Sensor, Bank 1, Sensor 3. This sensor plays a crucial role in emission management, particularly on diesel engines equipped with a Diesel Oxidation Catalyst (DOC) or a Diesel Particulate Filter (DPF).
Possible Causes of Code P242C
- Faulty EGTS (Bank 1, Sensor 3).
- Electrical Circuit Problem: Open circuit, short circuit, or damaged wiring.
- Faulty Connections: Corrosion, bent pins, or loose connections on the connector.
- Exhaust Leaks near the sensor or the aftertreatment system.
- Sensor Fouling: Buildup of soot or particles disrupting the measurement.
Associated Symptoms
- Illuminated Check Engine Light (or warning message).
- Possible decrease in engine performance (depending on the severity of the fault).
- Risk of increased fuel consumption or higher pollutant emissions.
EGTS Function
Located upstream of the DOC (Diesel Oxidation Catalyst) or DPF (Diesel Particulate Filter), the EGTS measures the exhaust gas temperature and converts it into an electrical signal (voltage) sent to the PCM (Powertrain Control Module). This data allows the PCM to:
- Control DPF regenerations.
- Optimize fuel dosing.
- Limit pollutant emissions.
Code P242C is triggered when the PCM detects an abnormal voltage or inconsistency in the sensor values (e.g., unrealistic temperature).
Diagnostic and Repair Procedures
- Visual Inspection:
- Check the EGTS, its connector, and the wiring harness for damage, corrosion, or exposed wires.
- Inspect the exhaust system for leaks.
- Electrical Testing:
- Use a multimeter to measure the sensor’s resistance and voltage (compare with manufacturer specifications).
- Check for continuity and the absence of short circuits in the wiring.
- Cleaning or Replacement:
- Remove and clean the sensor if fouled (using an appropriate cleaner).
- Replace the EGTS if faulty or out of specification.
- Code Reset:
- Clear the P242C code after repair using a diagnostic tool, then test drive the vehicle to confirm the issue is resolved.
Practical Tips
- Specific Sensor: Always use a sensor compatible with your vehicle’s Bank 1, Sensor 3.
- DOC/DPF: Inspect these components if the code persists, as severe fouling can distort measurements.
- PCM Software: In rare cases, a PCM software update may be necessary.
For detailed instructions, refer to the manufacturer’s repair manual or consult a certified professional.
(Note: This code primarily concerns diesel vehicles equipped with emission aftertreatment systems.)