AutoCodes – Generic – B1370:04

B1370:04 Code - Control Module Ignition ON and Start Circuit Short to Ground

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: B1370:04 indicates Control Module Ignition ON and Start Circuit Short to Ground.
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 809

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 B1370:04 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.
The Diagnostic Trouble Code (DTC) will be set when the Ignition circuit is shorted to ground or open.

OBDII Code B1370:04 - Control Module Ignition ON and Start Circuit Short to Ground - AutoCodes.com — B1370:04 Code - Control Module Ignition ON and Start Circuit Short to Ground

What does this mean?

What are the Possible Causes of the DTC B1370:04?

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 B1370:04?

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

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B1370:04 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.

Frequently Asked Questions about B1370:04 Code

1. What are the common symptoms of OBDII code B1370:04?

- Common symptoms include a no-start condition, engine stalling, and potentially a loss of communication with the vehicle's control modules.

2. What could cause the Control Module Ignition ON and Start Circuit Short to Ground?

- This code is usually triggered by a short to ground in the wiring harness, a faulty ignition switch, or a defective control module.

3. How can I diagnose the cause of OBDII code B1370:04?

- Diagnosing this code typically involves performing a thorough visual inspection of the wiring harness, testing the ignition switch, and using a multimeter to check for shorts to ground.

4. Is it safe to continue driving with OBDII code B1370:04 active?

- It is not recommended to drive the vehicle with this code active, as it can lead to potential starting issues and cause further damage to the control modules.

5. Can a DIY enthusiast repair OBDII code B1370:04 at home?

- Depending on the root cause, some DIY enthusiasts may be able to repair this issue at home by following a detailed diagnostic and repair procedure. However, professional assistance may be required for complex cases.

6. How much does it typically cost to repair OBDII code B1370:04?

- The cost of repairing this code can vary significantly depending on the cause of the issue. Simple fixes like repairing a wiring harness may cost less than replacing a control module.

7. Is it necessary to clear the code after repairing OBDII code B1370:04?

- Yes, it is important to clear the code using an OBDII scanner after repairing the underlying issue. This will reset the vehicle's computer and turn off the Check Engine Light.

8. Are there any preventive measures to avoid OBDII code B1370:04 in the future?

- Regular maintenance, such as checking the condition of the wiring harness and ensuring proper electrical connections, can help prevent issues that may trigger this code.

9. Can extreme weather conditions contribute to triggering OBDII code B1370:04?

- Extreme weather conditions can potentially exacerbate existing electrical issues in the vehicle, leading to the triggering of this code. It is important to keep the vehicle well maintained in all weather conditions.

10. How long does it typically take to repair OBDII code B1370:04?

- The repair time for this code can vary depending on the complexity of the issue and the availability of parts. Simple fixes may take a few hours, while more intricate repairs could require a day or more.