Cabin Ionizer Module Fault
The B0891 code means the vehicle's onboard diagnostic system has detected: Cabin Ionizer Module Fault. This is a low severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $50 - $300 (parts and labor)
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Common Symptoms
- Auto recirculation not activating
- Air quality indicator on dashboard
- Cabin air feels stuffy
- Air purifier not functioning
Probable Causes (Ranked by Likelihood)
- Faulty cabin air quality sensor Very High
- Contaminated sensor element High
- Sensor wiring damage Moderate
- HVAC module input fault Low
Step-by-Step Diagnostic Procedure
-
Test air quality sensor output with scan tool
-
Inspect sensor for contamination
-
Check sensor connector and wiring
-
Verify HVAC module receives sensor data
Frequently Asked Questions
What does the cabin air quality sensor do?
It detects pollutants, exhaust fumes, and particles in the outside air and automatically switches to recirculation mode to protect cabin air quality.
How often should the cabin air filter be changed?
Cabin air filters should be replaced every 15,000-30,000 miles or annually, whichever comes first.
Does this code affect the regular HVAC system?
No, the air quality sensor only controls automatic recirculation switching. Manual HVAC controls still work normally.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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