P0474: Exhaust Pressure Sensor Circuit Intermittent
The P0474 code indicates that the Engine Control Module (ECM) has detected an intermittent signal from the exhaust pressure sensor circuit. This sensor monitors backpressure in the exhaust system, often used for diesel particulate filter (DPF) regeneration and EGR control. An intermittent fault means the signal is erratic or drops out temporarily, which can be caused by wiring issues, loose connections, or a failing sensor.
01. Most Common Causes
- Faulty exhaust pressure sensor
- Damaged or corroded wiring/connectors
- Loose electrical connection
- Exhaust system leaks affecting pressure readings
02. Symptoms You Will Notice
- Check Engine Light on
- Reduced engine performance
- Poor fuel economy
- Possible DPF regeneration issues
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect the exhaust pressure sensor and wiring for damage, corrosion, or loose connections.
Step 3: Test sensor voltage and ground with a multimeter; compare to manufacturer specs.
Step 4: Check for exhaust leaks near the sensor mounting point.
Step 5: If wiring and connections are good, replace the exhaust pressure sensor.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally safe for short trips, but prolonged driving may cause reduced performance, poor fuel economy, and potential DPF clogging. It's best to diagnose and fix 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.