AutoCodes – Cadillac – B1372 Cadillac

B1372 Cadillac Code - Device Ignition On and Start Circuit Low

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: B1372 Cadillac indicates Device Ignition On and Start Circuit Low.
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 917

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 Mar 17, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B1372 Cadillac Description

The vehicle Power Mode Master (PMM) is the Body Control Module (BCM). The ignition switch is a low current switch with multiple discrete ignition switch signals to the PMM for determination of the power mode. The PMM receives the ignition switch signals, and additionally a reference voltage signal from the BCM, through the ignition switch, and back to the BCM. There are redundancies within the PMM system that can allow operation of certain subsystems when there are faults in the ignition switch circuits. Other information such as serial data input from other modules and DTCs is also used to determine what power mode signals and information is transmitted by the PMM. The BCM logic uses all this information 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 PMM serial data message does not match what the individual module can detect from its own connections.
The PMM will activate relays and other direct outputs of the PMM 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 short to ground, the B+ circuit fuse to the ignition switch will open.

OBDII Code B1372 Cadillac - Device Ignition On and Start Circuit Low - AutoCodes.com — B1372 Cadillac Code - Device Ignition On and Start Circuit Low

What does this mean?

What are the Possible Causes of the DTC B1372 Cadillac?

Faulty Ignition Switch
Ignition Switch harness is open or shorted
Ignition Switch circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B1372 Cadillac?

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 B1372 Cadillac 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 B1372 Cadillac Code

1. What are the common symptoms of OBDII code B1372 in a Cadillac related to the Device Ignition On and Start Circuit Low?

- Common symptoms include difficulty starting the vehicle, intermittent ignition issues, and possible illuminated warning lights on the dashboard.

2. What are the possible causes of the Device Ignition On and Start Circuit Low code B1372 in a Cadillac?

- Causes may include a faulty ignition switch, damaged wiring or connectors in the ignition circuit, or a problem with the ignition control module.

3. How can I diagnose the Device Ignition On and Start Circuit Low code B1372 in my Cadillac?

- Diagnose the code by performing a thorough inspection of the ignition system, checking for loose connections, testing the ignition switch, and using a multimeter to measure voltage in the circuit.

4. Is it safe to continue driving my Cadillac with the B1372 code related to Device Ignition On and Start Circuit Low?

- It is not recommended to drive the vehicle with this code present, as it can lead to potential starting issues and further electrical problems.

5. Can I repair the B1372 code related to Device Ignition On and Start Circuit Low in my Cadillac myself?

- Depending on your skill level and access to tools, you may be able to address the issue yourself by inspecting and repairing any damaged wiring or replacing faulty components like the ignition switch.

6. How much does it typically cost to repair the Device Ignition On and Start Circuit Low code B1372 in a Cadillac at a professional mechanic or dealership?

- Repair costs can vary but may range from $100 to $300 or more, depending on the extent of the issue and the labor involved in diagnosing and fixing the problem.

7. Are there any preventive measures I can take to avoid encountering the B1372 code related to Device Ignition On and Start Circuit Low in my Cadillac?

- Regularly inspect and maintain your vehicle's ignition system, address any warning signs promptly, and avoid overloading the electrical system to help prevent this code from occurring.

8. Will resetting the OBDII system clear the B1372 code related to Device Ignition On and Start Circuit Low in my Cadillac?

- Resetting the OBDII system may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to reappear after driving the vehicle.

9. Can extreme weather conditions affect the likelihood of the Device Ignition On and Start Circuit Low code B1372 appearing in my Cadillac?

- Yes, extreme temperatures or moisture can potentially exacerbate electrical issues and increase the chances of encountering this specific OBDII code.

10. Is the Device Ignition On and Start Circuit Low code B1372 a common problem in Cadillacs, or is it more likely due to a specific issue in my vehicle?

- While this code may not be as common as some other OBDII codes, it is still encountered in Cadillacs and usually indicates a specific issue within the ignition system that needs attention.