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Home >> Buick >> 2003 >> Century Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics - 3.1L Engine >> Diagnostic Tests >> DTC P0172: Fuel Trim System Rich >> Test Description

Test Description

The numbers below refer to the step numbers in the diagnostic procedure.

  1. 5  - If the conditions were not corrected, refer to FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 3.1L CENTURY, GRAND PRIX & MALIBU article for a possible fuel condition.
  2. 6  - An EVAP canister that is saturated will cause a rich condition. Fuel in the vacuum line to the fuel pressure regulator indicates a leaking regulator. If the conditions were not corrected, a worn cam, worn intake or exhaust valves, or other engine mechanical failure may be at fault.

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