OBD Codes List

Diagnostic reference · P03D8

P03D8

Cylinder 7 Pressure Variation Low

System
Ignition and misfire (P code)
Lamp
Check Engine Light
Category
Powertrain - Ignition

What it means

P03D8 means Cylinder 7 Pressure Variation Low.

Check these first

  • A weak cylinder 7 contributing less than the rest
  • A leaking valve or ring on cylinder 7
  • An injector delivering short on cylinder 7
  • A failed cylinder 7 pressure sensor
  • Worn cam lobes on cylinder 7

What to do next

  1. Compare cylinder 7 pressure balance across the cylinders on a scan tool
  2. Run a compression and leakdown test on cylinder 7
  3. Test the cylinder 7 injector for flow
  4. Check the cylinder 7 sensor against a known good one
  5. Repair the valve, ring or injector fault if the test confirms it
  6. Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.