Exhaust Gas Temperature Sensor Circuit Bank 1 Sensor 2 Open (Generic)
The P4004 code means the vehicle's onboard diagnostic system has detected: Exhaust Gas Temperature Sensor Circuit Bank 1 Sensor 2 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
- DPF regeneration will not complete
- Reduced engine power mode active
- Exhaust temperature monitoring disabled
- Potential DPF damage from uncontrolled regen
Probable Causes (Ranked by Likelihood)
- Open circuit in EGT sensor 2 wiring Very High
- Failed EGT sensor 2 High
- Burnt wiring near DPF housing Moderate
- Connector melted from excessive heat Low
Step-by-Step Diagnostic Procedure
-
Check EGT sensor 2 resistance at the connector
-
Inspect wiring between sensor 2 and PCM for breaks
-
Check connector at DPF for heat damage
-
Swap with a known good sensor to verify diagnosis
Frequently Asked Questions
Where is EGT sensor 2 located?
EGT sensor 2 is typically located downstream of the diesel particulate filter. It monitors the temperature after the DPF to verify regeneration effectiveness.
Can I drive without sensor 2 working?
The vehicle will likely enter reduced power mode and DPF regeneration will be disabled. This can lead to a completely clogged DPF which is very expensive to replace.
Is sensor 2 harder to replace than sensor 1?
It depends on the vehicle. On some models, sensor 2 is easier to access. On others, it is buried under heat shields near the DPF. Expect $150-400 for the repair.
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