Exhaust Gas Temperature Sensor Circuit Bank 2 Sensor 1 Open (Generic)
The P4008 code means the vehicle's onboard diagnostic system has detected: Exhaust Gas Temperature Sensor Circuit Bank 2 Sensor 1 Open (Generic). This is a critical severity code.
- Keep driving?
- No -- stop driving
- DIY difficulty
- hard
- Estimated cost
- $100 - $400 (parts and labor)
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Common Symptoms
- Check Engine Light on
- Reduced engine power mode
- Turbo boost limited on bank 2
- DPF regeneration disabled
- High exhaust emissions
Probable Causes (Ranked by Likelihood)
- Open circuit in bank 2 EGT sensor 1 wiring Very High
- Failed EGT sensor on bank 2 exhaust High
- Connector disconnected or broken Moderate
- PCM driver circuit failure Low
Step-by-Step Diagnostic Procedure
-
Check bank 2 EGT sensor 1 resistance
-
Inspect wiring harness on bank 2 exhaust side for damage
-
Verify connector is fully seated and locked
-
Test PCM driver circuit for bank 2 EGT input
Frequently Asked Questions
What is bank 2?
Bank 2 refers to the side of the engine that does not contain cylinder 1. On V-configuration engines, bank 2 is the opposite side from bank 1.
Why is P4008 critical?
Without bank 2 EGT data, the PCM cannot monitor exhaust temperatures for turbo protection or DPF regeneration on that side, which can lead to component damage.
Is P4008 common on diesel trucks?
It is relatively common on high-mileage diesel trucks. The harsh exhaust environment degrades wiring and connectors over time.
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