Exhaust Gas Temperature Sensor Circuit Low (Bank 2 Sensor 1)
The P0548 code means the vehicle's onboard diagnostic system has detected: Exhaust Gas Temperature Sensor Circuit Low (Bank 2 Sensor 1). This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $100 - $400 (parts and labor)
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Common Symptoms
- Check Engine Light on
- Bank 2 DPF regeneration issues
- Reduced power
- Exhaust system management limited
Probable Causes (Ranked by Likelihood)
- Short to ground in Bank 2 EGT sensor wiring Very High
- Failed Bank 2 EGT sensor with internal short High
- Moisture in Bank 2 EGT sensor connector Moderate
- Wiring damage near Bank 2 exhaust manifold Moderate
Step-by-Step Diagnostic Procedure
-
Compare Bank 2 EGT reading to Bank 1; a much lower Bank 2 reading confirms the circuit issue
-
Disconnect the Bank 2 EGT sensor and check for short to ground on the signal wire
-
Inspect the Bank 2 sensor connector for moisture or corrosion
-
Measure Bank 2 sensor resistance and compare to Bank 1 sensor
Frequently Asked Questions
Is P0548 diagnosis the same as P0545?
The diagnostic approach is the same but focused on the Bank 2 side. Check the Bank 2 EGT sensor, its wiring, and connector. The root causes are identical; only the location differs.
Can exhaust leaks affect EGT sensor readings?
Yes. An exhaust leak before the EGT sensor location can introduce cooler ambient air, causing lower temperature readings. However, a circuit low code typically indicates an electrical issue rather than an actual temperature change.
How hot do exhaust gas temperatures get?
Normal exhaust gas temperatures range from 400F to 1200F depending on engine load and type. During DPF regeneration on diesels, temperatures can reach 1100F to 1400F. EGT sensors must withstand these extreme conditions.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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