P2477: Exhaust Gas Temperature Sensor Circuit Intermittent/Erratic Bank 2 Sensor 4
The P2477 code indicates an intermittent or erratic signal from the exhaust gas temperature (EGT) sensor located on Bank 2, Sensor 4. This sensor monitors exhaust temperature to protect the diesel particulate filter (DPF) and catalytic converter. An intermittent signal can result from wiring issues, connector corrosion, or a failing sensor. This may cause incorrect regeneration cycles, reduced fuel economy, and potential DPF damage.
1. Most Common Causes
- Faulty exhaust gas temperature sensor
- Damaged or corroded wiring/connectors
- Intermittent short or open in the sensor circuit
- Exhaust leaks near the sensor
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel economy
- DPF regeneration issues
- Possible limp mode activation
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect the EGT sensor wiring and connector for damage or corrosion.
Step 3: Use a multimeter to check sensor resistance and compare to manufacturer specs.
Step 4: Monitor live data for erratic temperature readings while wiggling the harness.
Step 5: If wiring is good, replace the EGT sensor.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can lead to DPF clogging and reduced engine performance. Short trips may be okay, but prompt diagnosis is advised.
How much does it cost to fix?▼
Typically $50-$150 for parts and labor, depending on sensor location and labor rates.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.