AutoCodes – Cadillac – P1138 Cadillac

P1138 Cadillac Code - HO2S Circuit High Voltage Sensor 2

Quick Answer

In order to control emissions, a catalytic converter converts any harmful exhaust emissions into harmless water vapor and carbon dioxide. Common causes include Faulty HO2S Bank 1 Sensor 2, HO2S Bank 1 Sensor 2 harness is open or shorted, HO2S Bank 1 Sensor 2 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: P1138 Cadillac indicates HO2S Circuit High Voltage Sensor 2.
Common causes: Common causes include Faulty HO2S Bank 1 Sensor 2, HO2S Bank 1 Sensor 2 harness is open or shorted, HO2S Bank 1 Sensor 2 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 4,378

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jul 12, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P1138 Cadillac Description

In order to control emissions, a catalytic converter converts any harmful exhaust emissions into harmless water vapor and carbon dioxide. The Powertrain Control Module (PCM) can monitor this process by using a rear Heated Oxygen Sensor 2 (HO2S 2). The HO2S 2, located in the exhaust stream past the catalytic converter, produces an output signal which indicates the storage capacity of the catalyst. This signal indicates the catalyst's ability to effectively convert the exhaust emissions. If the catalyst is functioning properly, the HO2S 2 signal will be far less active than the signal produced by the front Heated Oxygen Sensor 1 (HO2S 1).

OBDII Code P1138 Cadillac - HO2S Circuit High Voltage Sensor 2 - AutoCodes.com — P1138 Cadillac Code - HO2S Circuit High Voltage Sensor 2

What does this mean?

What are the Possible Causes of the DTC P1138 Cadillac?

Faulty HO2S Bank 1 Sensor 2
HO2S Bank 1 Sensor 2 harness is open or shorted
HO2S Bank 1 Sensor 2 circuit poor electrical connection

How to Fix the DTC P1138 Cadillac?

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 P1138 Cadillac 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.