Bulletin No.:

Service Bulletin

Date:

19-NA-049
March, 2019

TECHNICAL
Subject:

Reduced Propulsion Power without DTCs on Higher Mileage
Vehicles (with P1.4 Cell Chemistry)
This Bulletin replaces PIC6309A. Please discard PIC6309A.

Brand:

Model:

Chevrolet

Volt

Opel /
Vauxall

Ampera

Model Year:

VIN:

from

to

2011

2012

2012

from

2012

to

Engine:

Transmission:

1.4L (LUU)

4ET50
Automatic
(MKA)

Involved Region or Country

North America, Europe, N.A. Export Regions

Additional Options (RPOs)

Without RPO YK8

Condition

Some customers may state that they occasionally see a Propulsion Power is Reduced
message in the Driver Information Center (DIC) that was not present under the same
driving conditions previously. They may also state the engine speed was very high at the
time of the message or that the engine compartment had a hot smell.

Cause

When the battery pack is over-discharged, the system will enter a reduced power mode
until the battery state of charge self-recovers by using aggressive engine charging. This
may be caused by a controls issue with normal wear of the high voltage battery. It does
not necessarily indicate that the there is a problem with the battery itself.

Copyright 2019 General Motors LLC. All Rights Reserved.

Page 2

March, 2019

Bulletin No.: 19-NA-049

• If there are ANY diagnostic codes set that would affect propulsion, consider
diagnosing them first prior to applying this bulletin.
• If there are NO diagnostic codes present that would affect propulsion, then this
document may apply to the customer's situation.
There are some cases where a Propulsion Power is Reduced message is
considered normal. For example, any Volt or Ampera, climbing a steep grade at
interstate speeds without proper use of Mountain Mode will encounter this same
message without DTCs. If this is the case, refer the customer to proper use of Mountain
Mode in the owner’s manual. Also, extreme outside temperatures, especially in winter,
may cause the message to appear until the battery temperature has stabilized.
If a Propulsion Power is Reduced message occurs during regular operation, and
there are no DTCs present, then determine the chemistry of the battery currently in the
vehicle using the chemistry determination procedure, SI Document ID 4877428.
• If the vehicle has P1.4 cell chemistry on board, then reprogram the Hybrid
Powertrain Control Module 2 (HPCM2) for a new calibration to help alleviate the
condition. Refer to Hybrid Powertrain Control Module 2 Programming and Setup in SI.

Correction

Important: After flashing the update into the HPCM2, the technician should
perform a capacity reset in the HPCM2 using GDS2; then fully charge the vehicle
prior to delivery to the customer.
• If the vehicle has newer cell chemistry than P1.4, such as 2012 vehicles built
with RPO code YK8 or if the vehicle has been serviced with a newer battery
chemistry in the past, then the bulletin DOES NOT apply and reprogramming will not
correct the condition.
After reprogramming, some customers may notice a slight reduction in EV range due to
the battery no longer being over-discharged. The EV range achieved previously was due
to the over-discharged condition. The new calibration properly aligns the expected EV
range with the age of the vehicle.

Parts Information
No parts are required for this repair.

Warranty Information
For vehicles repaired under the Powertrain coverage,
use the following labor operation. Reference the
Applicable Warranties section of Investigate Vehicle
History (IVH) for coverage information.
Labor
Operation
5080258*

Description

Labor Time

HPCM2 reprogramming for
Reduced Propulsion Power

0.4 hr

*This is a unique Labor Operation for Bulletin use only.

Version

1

Modified

Released March 11, 2019

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these
technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper
service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a
job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your
vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the
information.

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