AutoCodes – GMC – P1B99 GMC

P1B99 GMC Code - Hybrid/Electric Vehicle Battery 61 Circuit Performance

Quick Answer

The Hybrid/Electric Vehicle battery pack contains 288 cells. Common causes include Faulty Hybrid/Electric Vehicle Battery Pack, Faulty Hybrid/Electric Vehicle Battery Interface Control Module. 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: P1B99 GMC indicates Hybrid/Electric Vehicle Battery 61 Circuit Performance.
Common causes: Common causes include Faulty Hybrid/Electric Vehicle Battery Pack, Faulty Hybrid/Electric Vehicle Battery Interface Control Module.
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 754

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 12, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1B99 GMC Description

The Hybrid/Electric Vehicle battery pack contains 288 cells. Groups of three cells are welded together in parallel. There are a total of 96 cell groups in the hybrid/EV battery pack assembly. These cell groups are electrically connected in-series. Each individual cell group is rated at 3.7 V, for a nominal system voltage of 355 V direct current. The battery cells are also grouped together into three sections. The first 90 cells/30 cell groups make up battery section one. This section is adjacent to the cowl and contains batteries 67 through to 96. Battery section two is located behind section one. It is made up of 72 cells/24 cell groups and contains batteries 43 through to 66. The transverse battery section is section number three, it is made up of the remaining 126 cells/42 cell groups and contains batteries 1 through to 42. The three battery sections are individually serviceable components.
The battery energy control module monitors the voltage of the 96 battery cell groups through the four hybrid/EV battery interface control modules. Voltage sense circuits are attached to each individual cell group, and these sense circuits terminate at a connector located on the top surface of the battery section. A serviceable auxiliary battery wiring harness joins this connector to a hybrid/EV battery interface control module, also located on the top surface of the battery section. The hybrid/EV battery interface control module encodes the voltage reading and transmits it to the battery energy control module through the battery control harness. There is one hybrid/EV battery interface control module located on battery sections one and two, and two hybrid/EV battery interface control modules associated with battery section three. The hybrid/EV battery interface control module, battery energy control module wiring harness, auxiliary battery wiring harness, and battery energy control module are all considered serviceable components.
The battery energy control module will determine when a fault condition is present. Diagnostics and system status are communicated from the battery energy control module to hybrid/EV powertrain control module 2 through serial data. The hybrid/EV powertrain control module 2 is the host controller for diagnostic trouble code information.

OBDII Code P1B99 GMC - Hybrid/Electric Vehicle Battery 61 Circuit Performance - AutoCodes.com — P1B99 GMC Code - Hybrid/Electric Vehicle Battery 61 Circuit Performance

What does this mean?

What are the Possible Causes of the DTC P1B99 GMC?

Faulty Hybrid/Electric Vehicle Battery Pack
Faulty Hybrid/Electric Vehicle Battery Interface Control Module

How to Fix the DTC P1B99 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 P1B99 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.

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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 P1B99 GMC Code

1. What are the common symptoms of OBDII code P1B99 in GMC hybrid/electric vehicles?

- Common symptoms include reduced hybrid system performance, decreased fuel efficiency, and potential issues with the vehicle's battery charging.

2. What are the possible causes of OBDII code P1B99 in a GMC hybrid/electric vehicle?

- The code P1B99 typically indicates a fault in the Hybrid/Electric Vehicle Battery 61 Circuit, which can be caused by issues such as battery pack degradation, wiring problems, or faulty sensors.

3. How can I diagnose the OBDII code P1B99 in my GMC hybrid/electric vehicle?

- Diagnosing code P1B99 usually involves conducting a thorough inspection of the hybrid/electric vehicle battery system, checking for loose connections, testing the battery cells, and using a diagnostic scanner to analyze the code.

4. Can I continue driving my GMC hybrid/electric vehicle with OBDII code P1B99 present?

- It is not recommended to continue driving the vehicle with code P1B99 present, as it can lead to further damage to the hybrid battery system and potentially impact the vehicle's performance and safety.

5. How can I repair OBDII code P1B99 in my GMC hybrid/electric vehicle?

- Repairing OBDII code P1B99 may involve replacing faulty battery components, repairing damaged wiring, resetting the battery management system, or seeking assistance from a professional mechanic with experience in hybrid/electric vehicle systems.

6. Is it safe to reset the OBDII code P1B99 in my GMC hybrid/electric vehicle without addressing the underlying issue?

- Resetting the code without addressing the underlying issue may temporarily clear the warning light, but it is not a recommended long-term solution as the problem may persist and cause further complications.

7. How much does it typically cost to repair OBDII code P1B99 in a GMC hybrid/electric vehicle?

- The cost of repairing code P1B99 can vary depending on the specific issue causing the code, the extent of the damage, and the labor rates of the repair facility. It is advisable to obtain a diagnosis and estimate from a qualified technician.

8. Can OBDII code P1B99 be triggered by a simple battery system reset in a GMC hybrid/electric vehicle?

- In some cases, performing a battery system reset may temporarily clear the code P1B99, especially if the issue was due to a temporary fault. However, if the code reappears, it indicates a persistent problem that needs to be addressed.

9. Are there any preventive maintenance tips to avoid OBDII code P1B99 in GMC hybrid/electric vehicles?

- Regularly inspecting the hybrid battery system, maintaining proper charging habits, avoiding deep discharges, and following the manufacturer's recommended maintenance schedule can help prevent issues that may trigger code P1B99.

10. Can I use an OBDII scanner to clear OBDII code P1B99 in my GMC hybrid/electric vehicle?

- While an OBDII scanner can clear the code temporarily, it is important to diagnose and address the root cause of the issue triggering code P1B99 to prevent it from reoccurring.