P242C - Exhaust Gas Temperature Sensor Circuit Low Bank 1 Sensor 3
The P242C code indicates that the Engine Control Module (ECM) has detected a low voltage condition in the exhaust gas temperature (EGT) sensor circuit for Bank 1, Sensor 3. This sensor is typically located downstream of the diesel particulate filter (DPF) or in the exhaust system after the catalytic converter. A low voltage reading suggests a short to ground, a faulty sensor, or wiring issues. This can affect emissions control and DPF regeneration, potentially leading to reduced fuel economy and increased emissions.
01. Most Common Causes
- Faulty exhaust gas temperature sensor
- Short to ground in sensor wiring or connector
- Corroded or damaged sensor connector
- ECM software issues (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel economy
- Possible DPF regeneration issues
- Increased exhaust emissions
03. 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 sensor resistance and compare to manufacturer specifications; a short circuit indicates a faulty sensor.
Step 4: Check for voltage at the sensor connector with the ignition on; if voltage is low, repair wiring or replace sensor.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally safe to drive short distances, but prolonged driving may cause DPF clogging or reduced performance. It's best to diagnose and repair promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on the vehicle and shop rates.