AutoCodes – Generic – P1438

P1438 Code - A/C Evaporator Air Temperature Circuit Range/Performance

Quick Answer

The Engine Control Module (ECM) detected the evaporator control circuit had a range/performance condition. Common causes include Faulty A/C Evaporator Air Temperature Sensor, A/C Evaporator Air Temperature Sensor harness is open or shorted, A/C Evaporator Air Temperature Sensor circuit poor electrical connection. Severity is Low - monitor the vehicle and repair when practical. The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

What it means: P1438 indicates A/C Evaporator Air Temperature Circuit Range/Performance.
Common causes: Common causes include Faulty A/C Evaporator Air Temperature Sensor, A/C Evaporator Air Temperature Sensor harness is open or shorted, A/C Evaporator Air Temperature Sensor circuit poor electrical connection.
Severity: Low - monitor the vehicle and repair when practical.
Can I drive?: The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

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Code Popularity 11,178

How popular is this code, among other codes? Low

Repair Importance Level

Low (Monitor) (1 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Aug 22, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P1438 Description

The Engine Control Module (ECM) detected the evaporator control circuit had a range/performance condition.

OBDII Code P1438 - A/C Evaporator Air Temperature Circuit Range/Performance - AutoCodes.com — P1438 Code - A/C Evaporator Air Temperature Circuit Range/Performance

What does this mean?

What are the Possible Causes of the DTC P1438?

Faulty A/C Evaporator Air Temperature Sensor
A/C Evaporator Air Temperature Sensor harness is open or shorted
A/C Evaporator Air Temperature Sensor circuit poor electrical connection

How to Fix the DTC P1438?

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 P1438 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 P1438 code?

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Information for Specific Makes

P1438 Audi — EGR Valve 2 Open Circuit or Short Circuit to Ground
P1438 BMW — Purge Control Valve Control Open Circuit
P1438 Ford — A/C Evaporator Air Temperature Circuit Range/Performance
P1438 Honda — Motor Drive Module Overheating Signal Circuit
P1438 Lexus — HCAC System Variable Valve Circuit Low
P1438 Volkswagen — EGR Valve 2 Open Circuit or Short Circuit to Ground

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.