P03C2
Cylinder 5 Pressure Too Low
What it means
P03C2 means Cylinder 5 Pressure Too Low.
Check these first
- A leaking compression ring on cylinder 5
- A burnt or poorly sealing exhaust valve on cylinder 5
- A failed cylinder 5 pressure sensor reading low
- An intake or exhaust leak at cylinder 5
- Tight valve lash on cylinder 5
What to do next
- Run a compression test on cylinder 5 and compare to the rest
- Run a cylinder leakdown test on cylinder 5
- Compare the cylinder 5 pressure sensor to a known good one
- Check valve lash on cylinder 5
- Repair the valve or ring fault if the mechanical test confirms it
- Clear the code and retest
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Updated
Generic SAE J2012 definition. Last updated 2026-10-10.