AutoCodes – Buick – P15B9 Buick

P15B9 Buick Code - Electric A/C Compressor Control Module Ignition On/Start Switch Circuit Low Voltage

Quick Answer

The Body Control Module (BCM) controls the ignition run relay through the control circuit by applying voltage to the circuit. Common causes include Faulty Hybrid Powertrain Control Module 2, Hybrid Powertrain Control Module 2 harness is open or shorted, Hybrid Powertrain Control Module 2 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: P15B9 Buick indicates Electric A/C Compressor Control Module Ignition On/Start Switch Circuit Low Voltage.
Common causes: Common causes include Faulty Hybrid Powertrain Control Module 2, Hybrid Powertrain Control Module 2 harness is open or shorted, Hybrid Powertrain Control Module 2 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 964

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 Jan 03, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P15B9 Buick Description

The Body Control Module (BCM) controls the ignition run relay through the control circuit by applying voltage to the circuit. The ignition circuit is energized when the vehicle power mode is Vehicle ON or Vehicle in Service Mode. The hybrid powertrain control module 2 sends the vehicle power mode status in a serial data message to the battery charger control module, A/C compressor, battery energy control module, fuel pump control module and the Transmission Control Module (TCM).

OBDII Code P15B9 Buick - Electric A/C Compressor Control Module Ignition On/Start Switch Circuit Low Voltage - AutoCodes.com — P15B9 Buick Code - Electric A/C Compressor Control Module Ignition On/Start Switch Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P15B9 Buick?

Faulty Hybrid Powertrain Control Module 2
Hybrid Powertrain Control Module 2 harness is open or shorted
Hybrid Powertrain Control Module 2 circuit poor electrical connection

How to Fix the DTC P15B9 Buick?

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 P15B9 Buick 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 P15B9 Buick Code

1. What does OBDII code P15B9 mean for a Buick?

P15B9 indicates a low voltage issue in the Electric A/C Compressor Control Module's Ignition On/Start Switch Circuit, which can affect the operation of the air conditioning system.

2. What are the common symptoms of code P15B9?

Symptoms include the A/C not functioning properly, the A/C compressor not engaging, and potentially an illuminated check engine light or climate control warning.

3. What causes code P15B9 in a Buick?

Common causes include a weak or discharged vehicle battery, damaged wiring or connectors in the circuit, a faulty Electric A/C Compressor Control Module, or a malfunctioning ignition switch.

4. Can a bad battery trigger code P15B9?

Yes, a weak or failing battery can cause insufficient voltage to the control module, leading to the P15B9 code.

5. How is code P15B9 diagnosed?

Technicians typically check the battery voltage, inspect wiring and connectors for damage, test the ignition switch, and use a scan tool to monitor the circuit's voltage.

6. Can I drive my Buick with code P15B9?

While the vehicle may still be drivable, the A/C system might not function correctly, and ignoring the issue could lead to further electrical problems.

7. How do you fix code P15B9?

Repairs may involve charging or replacing the battery, repairing damaged wiring, replacing faulty connectors, or replacing the Electric A/C Compressor Control Module if found defective.

8. Is code P15B9 specific to Buick vehicles?

While this code can occur in other vehicles with similar systems, it is commonly associated with Buick models that use electric A/C compressors.

9. How much does it cost to fix code P15B9?

The cost varies depending on the cause, ranging from $100 for basic wiring repairs to $1,000 or more if the Electric A/C Compressor Control Module needs replacement.

10. Can resetting the code fix P15B9 permanently?

Clearing the code without addressing the root cause will only provide a temporary fix, as the issue will likely return. Proper diagnosis and repair are essential.