AutoCodes – GMC – B1370 2018 GMC Sierra

B1370 2018 GMC Sierra Code - Control Module Ignition ON and Start Circuit

Quick Answer

The vehicle Power Mode Master (PMM) is the Body Control Module (BCM). Common causes include Faulty Ignition Switch, Ignition Switch harness is open or shorted, Ignition Switch 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: B1370 2018 GMC Sierra indicates Control Module Ignition ON and Start Circuit.
Common causes: Common causes include Faulty Ignition Switch, Ignition Switch harness is open or shorted, Ignition Switch 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 297

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 Apr 17, 2023

Description
Possible Causes
How To Fix
Tech Notes ▶
Cost to Diagnose
FAQs
Comments
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Code B1370 2018 GMC Sierra Description

The vehicle Power Mode Master (PMM) is the Body Control Module (BCM). The ignition switch is a low-current switch with multiple discrete circuits to the BCM. The BCM logic uses the ignition switch positions to identify the operator's desired power mode and activate specific discrete signals, and serial data messages for the operation of different subsystems as necessary. Other modules which have switched voltage inputs may operate in a default mode if the Power Mode Master serial data message does not match what the individual module can detect from its own connections.
The Power Mode Master will activate relays and other direct outputs of the Power Mode Master as needed according to the calculated power mode. Some relays controlled by the BCM are switched ignition voltage outputs that are pass-through circuits within the BCM directly from the ignition switch. If these circuits are short to ground, the B+ circuit fuse to the ignition switch will open.

OBDII Code B1370 2018 GMC Sierra - Control Module Ignition ON and Start Circuit - AutoCodes.com — B1370 2018 GMC Sierra Code - Control Module Ignition ON and Start Circuit

What does this mean?

What are the Possible Causes of the DTC B1370 2018 GMC Sierra?

Faulty Ignition Switch
Ignition Switch harness is open or shorted
Ignition Switch circuit poor electrical connection
Faulty Body Control Module (BCM)
Faulty Instrument Cluster (If code is stored in Instrument Cluster)

How to Fix the DTC B1370 2018 GMC Sierra?

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

B1370:01 Control Module Ignition ON and Start Circuit Short to Battery
B1370:04 Control Module Ignition ON and Start Circuit Short to Ground or Open

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B1370 2018 GMC Sierra 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 B1370 2018 GMC Sierra code?

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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.

Frequently Asked Questions about B1370 2018 GMC Sierra Code

1. What does OBDII code B1370 for a 2018 GMC Sierra mean?

- The B1370 code indicates a problem with the Control Module Ignition ON and Start Circuit in the vehicle.

2. What are the common symptoms of OBDII code B1370 in a 2018 GMC Sierra?

- Common symptoms include difficulty starting the vehicle, intermittent starting issues, and possible stalling.

3. What are the possible causes of OBDII code B1370 in a 2018 GMC Sierra?

- The code B1370 can be triggered by a faulty ignition switch, a malfunctioning control module, damaged wiring, or a poor connection in the ignition circuit.

4. How can I diagnose the cause of OBDII code B1370 in my 2018 GMC Sierra?

- To diagnose the issue, you may need to check the ignition switch, inspect the control module, test the wiring for continuity, and ensure all connections are secure.

5. What are some repair tips for addressing OBDII code B1370 in a 2018 GMC Sierra?

- Repair tips include replacing a faulty ignition switch, repairing or replacing the control module, repairing damaged wiring, and ensuring all connections are clean and tight.

6. Can I drive my 2018 GMC Sierra with OBDII code B1370?

- It is not recommended to drive the vehicle with an active B1370 code, as it can lead to potential starting or stalling issues while on the road.

7. Is it safe to ignore OBDII code B1370 in a 2018 GMC Sierra?

- Ignoring the B1370 code can lead to more severe starting problems or the risk of the vehicle stalling unexpectedly, so it is best to address the issue promptly.

8. Will resetting the OBDII code B1370 in my 2018 GMC Sierra make it go away permanently?

- Resetting the code may temporarily clear the warning, but if the underlying issue causing the B1370 code is not addressed, it is likely to reappear.

9. How much does it typically cost to repair OBDII code B1370 in a 2018 GMC Sierra?

- The cost of repairing the B1370 code can vary depending on the specific cause, but it may involve parts and labor expenses ranging from $100 to $500 or more.

10. Can a DIY enthusiast fix OBDII code B1370 in a 2018 GMC Sierra?

- Depending on the root cause of the B1370 code, some DIY enthusiasts with automotive repair experience may be able to address the issue, but complex repairs may require professional assistance.