Code result
P04F9
Catalyst Heater Circuit Intermittent Bank 2
Moderate severity
What it means
Same as P04F8 on bank 2. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
Is it safe to drive?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Intermittent contact at connector
highOne of the most commonly reported causes for this code — check this first.
Connector with intermittent contact under vibration
lowLess common, but worth ruling out after the more likely causes.
Harness routed against vibrating component
lowLess common, but worth ruling out after the more likely causes.
Related help
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