Bulletin No.: 16-NA-054
Date: Feb-2016

Subject:

Diagnostic Tips for Stop/Start and AutoStop Operation

Brand:

Buick

Model:

Encore

Condition

Cause

Model Year:

VIN:

from

to

2016

2016

from

Engine:

Transmission:

1.4L Engine (RPO
LE2)

All

to

Some customers may comment on one or both of the following concerns:

•

Vehicle does not engage in AutoStop mode.

•

Vehicle automatically restarts during an AutoStop event.

A system malfunction may be the cause for loss of AutoStop, and a diagnostic trouble code (DTC) may be
set.
(Many of the conditions that allow, or shorten, an AutoStop are not visible or controlled by the operator. In
general, skipped AutoStop should be considered normal.)

Additional Options

Equipped with 1.4L Engine (RPO LE2) and Stop/Start System (RPO KL9)

Recommendation/Instructions
AutoStop mode is based on many factors. It is important first to verify that all conditions are met to enable AutoStop mode.

1

AutoStop may be deactivated if:
–

A minimum vehicle speed is not reached; minimum 20 km/h (12 mph) prior to first AutoStop, then 10 km/h (6 mph) thereafter.

–

The ambient, engine and transmission temperatures are not at the required operating ranges.

–

The shift lever is in any gear other than Drive.

–

The battery charge is low; less than 12V.

–

A/C compressor request from HVAC (A/C or Defrost modes).

Note: Refer to the table in the Stop/Start Enable Temperature Criteria below.

•
•

The interior comfort level has not been reached the required level for the climate control system or defog settings.
Humidity level too high inside the passenger compartment, commanding A/C compressor ON.

–

The AutoStop time is greater than two minutes.

–

Hood switch status shows open.

–

Brake pedal is not depressed beyond approximately 25%.

–

Accelerator pedal is being applied.

–

Brake booster vacuum is less than 45 kPa (7 psi).

–

Engine speed is above 1,000 RPM.

–

Battery state of charge as monitored in the ECM, is less than 60%.

Note: AutoStop will be disabled for entire ignition cycle if hood is open at the start of the ignition cycle.

Stop/Start Enable Temperature Criteria
Ambient Temperature

Engine Temperature

Transmission Temperature

-20°C

-5°C

15°C

35°C

45°C

(-4°F)

(23°F)

(59°F)

(95°F)

(113°F)

70°C

70°C

30°C

55°C

65°C

(158°F)

(158°F)

(86°F)

(131°F)

(149°F)

28°C

28°C

20°C

35°C

45°C

(82°F)

(82°F)

(68°F)

(95°F)

(113°F)

Stop/Start System Training
An overview course will be available at the following websites:
–

In the United States go to > www.centerlearning.com (will be available end of February, 2016)

–

In Canada go to > www.gmprocanada.com (availability in 2nd quarter of 2016)

2

Course Name

Description

Course Type

Intended Audience

16040.31W

12V Stop/Start System 2

Web

All Service Personnel

Customer Education Unique Operating Characteristics
Customer Education
It is imperative that the customer be well informed about the unique features and operational characteristics of their vehicle equipped with Stop/Start. For the
sales team to be fully prepared, they should use the Getting to Know Your Vehicle (GTK) guide (U.S. Only) as an outline when presenting the vehicle to the
customer. Additionally, service and parts leadership, service writers and technicians should familiarize themselves with these materials to avoid attempting
repair of normal operating characteristics.
Refer customers to the Owner Manual Stop/Start System and Climate Control Systems (Comfort/Eco Air Conditioning) (For Stop/Start Vehicles) sections for
operating characteristics.

Diagnostic Aids
When attempting to diagnose an AutoStart or AutoStop concern, the technician should review the Autostart Inhibit Reason and/or Autostop Disable Reason lists
available in the ECM. This list contains several parameters that are directly related to the Auto Start/Stop feature. They can be found in GDS 2 under ECM/Data
Display. These parameters list the current state of several parameters that can inhibit the Stop/Start feature. These parameters can be viewed while operating
the vehicle on the road or on a hoist with traction control turned off, to assist in determining why an Autostop did not occur.

Version

1

Modified

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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