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AutoCodes – GMC – P0381 GMC

P0381 GMC Code - Wait To Start Indicator Control Circuit

Quick Answer

Ignition voltage is supplied directly to the Wait To Start indicator. Common causes include Faulty Instrument Cluster, Instrument Cluster harness is open or shorted, Instrument Cluster 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
P0381 GMC indicates Wait To Start Indicator Control Circuit.
Common causes
Common causes include Faulty Instrument Cluster, Instrument Cluster harness is open or shorted, Instrument Cluster 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 12,531
How popular is this code, among other codes? Low
What is this?
Table of contents Created and updated by William Orellana on Jun 17, 2022
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Code P0381 GMC Description

Ignition voltage is supplied directly to the Wait To Start indicator. The Engine Control Module (ECM) controls the lamp by grounding the control circuit via an internal switch called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line which is monitored by the ECM. When the ECM is commanding a component ON, the voltage of the control circuit should be low, near zero volts. When the ECM is commanding the control circuit to a component OFF, the voltage potential of the circuit should be high, near battery voltage. The Diagnostic Trouble Code (DTC) will be set when the ECM detects an open circuit on the Wait To Start Indicator Control circuit for greater than 0.2 s.
OBDII Code P0381 GMC - Wait To Start Indicator Control Circuit - AutoCodes.com
P0381 GMC Code - Wait To Start Indicator Control Circuit
What does this mean?

What are the Possible Causes of the DTC P0381 GMC?

  • Faulty Instrument Cluster
  • Instrument Cluster harness is open or shorted
  • Instrument Cluster circuit poor electrical connection
  • Faulty Engine Control Module (ECM)

How to Fix the DTC P0381 GMC?

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 P0381 GMC 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 P0381 GMC code?

Need more information on how to fix the P0381 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0381 GMC code diagnosed by a professional: Find a repair shop in your area

Information for Specific GMC Models

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 P0381 GMC Code

1. What does the OBDII code P0381 mean on a GMC vehicle?

P0381 indicates an issue with the "Wait to Start Indicator Control Circuit," commonly found in diesel engines. It signals a problem with the system that manages the glow plug indicator light.

2. What are the common symptoms of the P0381 code in a GMC?

Symptoms may include the "Wait to Start" indicator light not functioning properly, difficulty starting the engine in cold temperatures, or no visible symptoms in some cases.

3. What causes the P0381 code to appear on a GMC?

The most common causes include a faulty glow plug control module, a burnt-out "Wait to Start" indicator bulb, damaged wiring or connectors, or a failing engine control module (ECM).

4. Can I still drive my GMC with the P0381 code?

Yes, you can usually drive the vehicle, but ignoring the issue may lead to starting problems, especially in cold weather, as the glow plug system is critical for diesel engine performance.

5. How can I diagnose the P0381 code on my GMC?

Start by checking the "Wait to Start" indicator bulb, inspecting the wiring and connectors for damage, and testing the glow plug control module. A scan tool can also confirm related faults.

6. What repairs are needed to fix the P0381 code?

Repairs may include replacing the "Wait to Start" indicator bulb, repairing or replacing damaged wiring, replacing the glow plug control module, or reprogramming the ECM if necessary.

7. How much does it cost to fix the P0381 code on a GMC?

Repair costs vary depending on the issue. Bulb replacement may cost $10-$50, while a glow plug control module replacement could range from $100 to $300, excluding labor costs.

8. Can a dead battery cause the P0381 code in a GMC?

A weak or dead battery is unlikely to directly cause this code, but low voltage can affect the glow plug system. Testing the battery and charging system is a good idea.

9. Does the P0381 code affect fuel efficiency in a GMC diesel vehicle?

This code typically does not affect fuel efficiency but may lead to harder starts, which can strain the starter and battery over time.

10. Can I reset the P0381 code without fixing the issue?

Clearing the code with a scan tool may temporarily remove it, but if the underlying problem isn’t resolved, the code will likely return.

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