AutoCodes – Generic – P027E

P027E Code - Cold Start Air Fuel Ratio Control System Command Lean

Quick Answer

The cold start emission reduction strategy controls air-fuel ratio to lean when the engine is started under cold conditions to lower the emission while the catalyst is not warmed up enough. Common causes include Faulty Powertrain Control Module (PCM), Powertrain Control Module harness is open or shorted, Powertrain Control Module circuit poor electrical connection. 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: P027E indicates Cold Start Air Fuel Ratio Control System Command Lean.
Common causes: Common causes include Faulty Powertrain Control Module (PCM), Powertrain Control Module harness is open or shorted, Powertrain Control Module circuit poor electrical connection.
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 484

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 Aug 16, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P027E Description

The cold start emission reduction strategy controls air-fuel ratio to lean when the engine is started under cold conditions to lower the emission while the catalyst is not warmed up enough. If the commanded air-fuel ratio is too lean or too rich compared to the target air-fuel ratio, the Powertrain Control Module (PCM) detects a malfunction and stores a Diagnostic Trouble Code (DTC).

OBDII Code P027E - Cold Start Air Fuel Ratio Control System Command Lean - AutoCodes.com — P027E Code - Cold Start Air Fuel Ratio Control System Command Lean

What does this mean?

What are the Possible Causes of the DTC P027E?

Faulty Powertrain Control Module (PCM)
Powertrain Control Module harness is open or shorted
Powertrain Control Module circuit poor electrical connection

How to Fix the DTC P027E?

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 P027E 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.

Need more information about the P027E code?

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Information for Specific Makes

P027E Acura — Cold Start Air Fuel Ratio Control System Command Lean
P027E Honda — Cold Start Air Fuel Ratio Control System Command Lean

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.