P2188 GMC - Fuel Trim System Rich at Idle

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3   
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Possible causes

  • Leaking fuel pressure regulator
  • Leaking fuel injector

When is the code detected?

The average long term fuel trim values at idle are less than -30 percent for 10 seconds

Possible symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

P2188 Gmc Description

The engine control module (ECM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. Fuel delivery is controlled differently during Open Loop and Closed Loop. During Open Loop, the ECM determines fuel delivery based on sensor signals without heated oxygen sensor (HO2S) input. During Closed Loop, the ECM adds HO2S inputs to calculate the short and long term fuel trim (FT) adjustments. If the HO2S indicates a lean condition, the fuel trim values will be above 0 percent. If the HO2S indicates a rich condition, the FT values will be below 0 percent. The short term FT values change rapidly in response to the HO2S voltage signals. The long term FT makes coarse adjustments in order to maintain an air/fuel ratio of 14.7:1.

OBDII Code P2188 Gmc - Fuel Trim System Rich at Idle  - AutoCodes.com

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