Exhaust Pressure Sensor Circuit Low
The P047C code indicates that the exhaust pressure sensor circuit is reading a voltage lower than the expected range. This sensor monitors backpressure in the exhaust system, typically on diesel engines with a variable geometry turbocharger or exhaust brake. A low circuit condition can be caused by a faulty sensor, wiring issues, or a problem with the sensor's reference voltage or ground. This can affect engine performance, turbocharger operation, and emissions control.
01. Most Common Causes
- Faulty exhaust pressure sensor
- Open or shorted wiring in sensor circuit
- Poor electrical connection at sensor connector
- Failed engine control module (ECM)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine power or limp mode
- Poor fuel economy
- Excessive exhaust smoke
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to verify the code and check for related codes.
Step 2: Inspect the exhaust pressure sensor connector and wiring for damage, corrosion, or loose connections.
Step 3: Measure the sensor's reference voltage (typically 5V) and ground at the connector.
Step 4: Test the sensor's output voltage while the engine is running; compare to manufacturer specifications.
Step 5: If sensor and wiring are okay, check for exhaust leaks or blockages that could affect pressure readings.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can cause reduced engine power, poor fuel economy, and potential damage to the turbocharger or emissions system.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on whether the sensor needs replacement or just a wiring repair.