AutoCodes – Generic – P138B

P138B Code - Glow Plug Module System Voltage

Quick Answer

The Engine Control Module (ECM) monitors the Glow Plug Control Module. Common causes include Faulty Glow Plug Control Module, Glow Plug Control Module harness is open or shorted, Glow Plug 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: P138B indicates Glow Plug Module System Voltage.
Common causes: Common causes include Faulty Glow Plug Control Module, Glow Plug Control Module harness is open or shorted, Glow Plug 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 18,430

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 24, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P138B Description

The Engine Control Module (ECM) monitors the Glow Plug Control Module. The ECM sets the OBDII code when Glow Plug Control Module is not working properly.

OBDII Code P138B - Glow Plug Module System Voltage - AutoCodes.com — P138B Code - Glow Plug Module System Voltage

What does this mean?

What are the Possible Causes of the DTC P138B?

Faulty Glow Plug Control Module
Glow Plug Control Module harness is open or shorted
Glow Plug Control Module circuit poor electrical connection

How to Fix the DTC P138B?

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 P138B 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 P138B code?

Need more information on how to fix the P138B code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P138B code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P138B Ford — Glow Plug Module System Voltage

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.

Frequently Asked Questions about P138B Code

1. What are common symptoms of OBDII code P138B, Glow Plug Module System Voltage?

- Common symptoms include hard starting, rough idling, decreased fuel efficiency, and the illumination of the Check Engine Light.

2. What are the possible causes of OBDII code P138B?

- Possible causes include a faulty glow plug module, wiring issues, poor electrical connections, or a malfunctioning engine control module.

3. How can I diagnose the cause of OBDII code P138B?

- Diagnosis typically involves checking the glow plug module and related wiring for damage, testing electrical connections, and using a diagnostic scanner to read live data and pinpoint the issue.

4. Can I still drive my vehicle with OBDII code P138B present?

- It is not recommended to drive with this code present, as it can lead to performance issues and potential engine damage if left unresolved.

5. How can I repair OBDII code P138B, Glow Plug Module System Voltage?

- Repair involves replacing the faulty glow plug module, repairing any damaged wiring or connections, and clearing the code using a diagnostic scanner.

6. Are there any preventative maintenance tips to avoid OBDII code P138B?

- Regularly checking and maintaining the glow plug system, keeping electrical connections clean and secure, and addressing any warning signs promptly can help prevent this code from occurring.

7. Will resetting the Check Engine Light resolve OBDII code P138B?

- Resetting the Check Engine Light may temporarily turn it off, but if the underlying issue causing the code is not addressed, the light will likely come back on.

8. Is it safe to ignore OBDII code P138B if my vehicle is still running fine?

- Ignoring the code can lead to potential engine performance issues and decreased fuel efficiency over time, so it is best to address it promptly.

9. Can a DIY enthusiast fix OBDII code P138B at home?

- Depending on your mechanical skills and access to tools, replacing the glow plug module and addressing wiring issues can be done at home, but professional help may be needed for accurate diagnosis.

10. How much does it typically cost to repair OBDII code P138B at a repair shop?

- The cost of repairing this code can vary depending on the labor rates in your area, but it generally ranges from $200 to $500, including parts and labor.