AutoCodes – Generic – P1338

P1338 Code - Cylinder 1 Glow Plug Offset Exceeded Learning Limit

Quick Answer

The Glow Plug Control Module has not learned the glow plug offset values. Common causes include Perform Glow Plug Learn procedure, Faulty Glow Plug 1, Glow Plug 1 harness is open or shorted. 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: P1338 indicates Cylinder 1 Glow Plug Offset Exceeded Learning Limit.
Common causes: Common causes include Perform Glow Plug Learn procedure, Faulty Glow Plug 1, Glow Plug 1 harness is open or shorted.
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 34,161

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 Sep 30, 2022

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P1338 Description

The Glow Plug Control Module has not learned the glow plug offset values. If a glow plug has been replaced and the glow plug learn was not performed, or if the Glow Plug Control Module experiences an Electronically Erasable Programmable Read Only Memory (EEPROM) error or data corruption, this Diagnostic Trouble Code (DTC) to set. The DTC will be set if the glow plug hot resistance is outside a predefined threshold.

OBDII Code P1338 - Cylinder 1 Glow Plug Offset Exceeded Learning Limit - AutoCodes.com — P1338 Code - Cylinder 1 Glow Plug Offset Exceeded Learning Limit

What does this mean?

What are the Possible Causes of the DTC P1338?

Perform Glow Plug Learn procedure
Faulty Glow Plug 1
Glow Plug 1 harness is open or shorted
Glow Plug 1 circuit poor electrical connection

How to Fix the DTC P1338?

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 does this mean?

Code Tech Notes

If a Glow Plug was replaced, perform a Glow Plug Learn procedure with a Scan Tool.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1338 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 P1338 code?

Need more information on how to fix the P1338 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1338 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P1338 Audi — Camshaft Position Sensor Bank 1 Open Circuit Or Short To Positive
P1338 Buick — Cylinder 1 Glow Plug Offset Exceeded Learning Limit
P1338 Cadillac — Cylinder 1 Glow Plug Offset Exceeded Learning Limit
P1338 Chevrolet — Cylinder 1 Glow Plug Offset Exceeded Learning Limit
P1338 GMC — Cylinder 1 Glow Plug Offset Exceeded Learning Limit
P1338 Hyundai — #8 MF Signal Line Short
P1338 Volkswagen — Camshaft Position Sensor Bank 1 Open Circuit Or Short To Positive

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 P1338 Code

1. What are the common symptoms of OBDII code P1338 (Cylinder 1 Glow Plug Offset Exceeded Learning Limit)?

- Common symptoms include rough idling, reduced engine performance, difficulty starting the engine, and illuminated Check Engine light.

2. What are the possible causes of OBDII code P1338?

- The code P1338 can be triggered by issues such as faulty glow plug, damaged wiring or connectors, ECM (Engine Control Module) malfunction, or software glitches.

3. How serious is OBDII code P1338?

- While the code itself may not cause immediate harm to the vehicle, it can lead to poor engine performance and increased emissions if left unaddressed.

4. Can I continue driving with OBDII code P1338?

- It is not recommended to continue driving with OBDII code P1338 as it can cause further damage to the engine and negatively impact fuel efficiency.

5. How can I diagnose OBDII code P1338?

- Diagnosing the code typically involves using an OBDII scanner to retrieve the code, inspecting the glow plug and related components, and testing the ECM for any faults.

6. What are the possible repair options for OBDII code P1338?

- Repair options may include replacing the faulty glow plug, repairing damaged wiring or connectors, resetting the ECM, or updating software as needed.

7. Can I fix OBDII code P1338 myself?

- While some DIY enthusiasts may be able to address simple causes such as a loose connection, it is recommended to seek professional help for proper diagnosis and repair.

8. How much does it cost to fix OBDII code P1338?

- The cost of fixing OBDII code P1338 can vary depending on the root cause of the issue, the labor rates in your area, and whether any parts need to be replaced.

9. Will OBDII code P1338 reset itself after repair?

- In most cases, the Check Engine light will turn off after the issue causing OBDII code P1338 is successfully repaired and the ECM resets itself.

10. How can I prevent OBDII code P1338 from occurring again?

- To prevent OBDII code P1338, it is important to perform regular maintenance on your vehicle, including checking the glow plugs and related components for any signs of wear or damage.