Exhaust Gas Temperature Sensor 1/3 Correlation Bank 1
The P20E3 code indicates a correlation issue between exhaust gas temperature (EGT) sensors 1 and 3 on Bank 1. These sensors monitor exhaust temperature for diesel particulate filter (DPF) regeneration and emission control. A correlation fault means the readings from sensor 1 (pre-DPF) and sensor 3 (post-DPF) are out of expected range, often due to sensor degradation, wiring issues, or exhaust leaks. This can lead to improper DPF regeneration, reduced fuel economy, and potential engine damage if ignored.
1. Most Common Causes
- Faulty or out-of-spec EGT sensor 1 or 3
- Exhaust leak between sensor 1 and sensor 3 locations
- Restricted or blocked exhaust system (clogged DPF, obstructed catalytic converter)
- Damaged, corroded, or high-resistance wiring or connector in the EGT sensor circuit
- Faulty PCM (engine control module) processing the sensor signals
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel economy
- DPF regeneration issues (frequent or incomplete)
- Possible limp mode or reduced engine power
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect EGT sensors 1 and 3 wiring and connectors for damage or corrosion.
Step 3: Compare sensor readings using a scan tool; sensor 1 should be hotter than sensor 3 under normal operation.
Step 4: Check for exhaust leaks near sensors using a smoke machine or visual inspection.
Step 5: Test sensor resistance and voltage per manufacturer specifications.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances. The issue can cause improper DPF regeneration, leading to clogged DPF, reduced performance, and potential engine damage. Have it diagnosed promptly.
How much does it cost to fix?▼
Typical repair costs range from $50 to $150 for sensor replacement, plus diagnostic fees. Labor and parts may vary by vehicle make and model.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.