Code result
P04F6
Catalyst Heater Circuit High Bank 1
Moderate severity
What it means
Same as P04F4 with the line shorted to supply or open - the ECU measures higher voltage than the commanded duty cycle allows.
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
Control line shorted to supply
highOne of the most commonly reported causes for this code — check this first.
Open in heater element or harness
mediumA plausible cause — test and verify before replacing parts.
Connector pins corroded - high contact resistance
lowLess common, but worth ruling out after the more likely causes.
Related help
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