Code result
P234D
Cylinder 9 Pressure Too Low
Moderate severity
What it means
Cylinder 9 measured peak combustion pressure is below the calibrated minimum — typically low compression, weak injection, or stuck-open exhaust valve.
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
Low compression on cylinder 9 (valves, rings, head gasket)
highOne of the most commonly reported causes for this code — check this first.
Injector flow too low
mediumA plausible cause — test and verify before replacing parts.
Related help
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