AutoCodes – GMC – P2188 GMC

P2188 GMC Code - Fuel Trim System Rich At Idle Bank 1

Quick Answer

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. Common causes include Dirty Air Filter, Dirty Mass Air Flow Sensor (MAF), Leaking fuel pressure regulator. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P2188 GMC indicates Fuel Trim System Rich At Idle Bank 1.
Common causes: Common causes include Dirty Air Filter, Dirty Mass Air Flow Sensor (MAF), Leaking fuel pressure regulator.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 6,326

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Sep 12, 2019

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code 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 Bank 1 - AutoCodes.com — P2188 GMC Code - Fuel Trim System Rich At Idle Bank 1

What does this mean?

What are the Possible Causes of the DTC P2188 GMC?

Dirty Air Filter
Dirty Mass Air Flow Sensor (MAF)
Leaking fuel pressure regulator
Leaking fuel injector
Faulty Mass Air Flow Sensor (MAF)

How to Fix the DTC P2188 GMC?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P2188 GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.