P2477: Exhaust Gas Temperature Sensor Circuit Intermittent/Erratic Bank 2 Sensor 4
The P2477 code indicates that the Engine Control Module (ECM) has detected 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 catalytic converter and diesel particulate filter (DPF) from overheating. An intermittent signal can be caused by wiring issues, poor connections, or a failing sensor. If left unresolved, it may lead to reduced engine performance, increased emissions, or potential damage to exhaust components.
01. Most Common Causes
- Faulty exhaust gas temperature sensor
- Damaged or corroded wiring/connectors
- Intermittent short or open in the sensor circuit
- Poor electrical connection at the sensor or ECM
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine power or limp mode
- Poor fuel economy
- Possible regeneration issues in diesel vehicles
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and record freeze frame data.
Step 2: Visually inspect the EGT sensor wiring and connector for damage, corrosion, or loose connections.
Step 3: Use a multimeter to check sensor resistance and compare to manufacturer specifications.
Step 4: Monitor sensor voltage with a scan tool while wiggling the wiring harness to reproduce the intermittent fault.
Step 5: If wiring is intact, replace the EGT sensor and clear the code.
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 the intermittent sensor can cause incorrect exhaust temperature readings, potentially leading to DPF or catalytic converter damage. You may experience reduced power or limp mode.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for a DIY replacement of the sensor, or $150 to $300 if professionally diagnosed and repaired, including parts and labor.