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Service bulletin PIT4593D

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id10112578
Published by NHTSA2017-08-15
Manufacturer's numberPIT4593D
Manufacturer's date2012-11-15
NHTSA componentSERVICE BRAKES, ELECTRIC; ELECTRICAL SYSTEM

NHTSA's summary

This Preliminary Information communication provides information to the technician about vehicles that have a lack of brake assist after disconnecting the battery or after the 12 volts battery has run low on voltage. The Antilock Braking System Malfunction Indicator Lamp may also be on. Technician may find Diagnostic Trouble Code C121D sym 00 or C056D sym 00 set in the Electronic Brake Control Module. Technician should be advised to wait for a period of at least 1 minute with the ignition in the "OFF" position prior to disconnecting the negative battery cable. Technician will need to follow these steps to repair the concern. 1. Install the negative battery cable to the battery. 2. Rotate the lever lock clockwise until an audible click is heard in order to connect the negative battery cable to the battery. 3. Position the negative battery cable insulating cover over the negative terminal. 4. Start the vehicle without stepping on the brake pedal. 5. Shut the vehicle "Off" for one minute. 6. Restart vehicle and check brakes for proper operation. 7. Clear codes in the Engine Control Module and the Electronic Brake Control Module.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Brakes, Electrical system

Trouble codes named

C056D, C121D

Vehicles listed
CADILLAC ESCALADE2009, 2010, 2011, 2012, 2013
CHEVROLET SILVERADO2009, 2010, 2011, 2012, 2013
CHEVROLET TAHOE2008, 2009, 2010, 2011, 2012, 2013
GMC SIERRA2009, 2010, 2011, 2012, 2013
GMC SIERRA DENALI2009, 2010, 2011, 2012, 2013 (the catalog's model; the bulletin names a series or trim of it)
GMC YUKON2008, 2009, 2010, 2011, 2012, 2013
GMC YUKON XL2008, 2009, 2010, 2011
GMC YUKON XL2012, 2013 (the catalog's model; the bulletin names a series or trim of it)

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Recalls for the same vehicles and component
20165972016-11-29. Electrical
20150022014-12-30. Electrical
14V8270002014-12-30. ELECTRICAL SYSTEM:IGNITION
20144322014-10-03. Electrical
14V6140002014-10-01. ELECTRICAL SYSTEM
20142772014-07-03. Electrical
14V4070002014-07-02. ELECTRICAL SYSTEM
10V2400002010-06-04. ELECTRICAL SYSTEM
08V4410002008-08-28. ELECTRICAL SYSTEM

A recall listed here may apply to some of the same vehicles. Only the manufacturer can say whether it applies to one vehicle.

Other bulletins for the same vehicles and component
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23-NA-0012025-04-28. Service bulletin. This service bulletin provides information for dealers/technicians on OnStar Module 2G Sunset Information.
13-08-116-001K2025-04-25. Service bulletin. The intent of this service bulletin is to identify aftermarket ALDL or DLC interface devices as potential sources for causing multiple customer concerns that do not have other diagnostic methods to identify them.
15-06-03-001F2025-04-15. Service bulletin. This service bulletin provides information to diagnose batteries that have set for a long period of time and/or cold weather climates and testing those batteries.
21-NA-0432025-02-12. Service bulletin. This bulletin advises the dealers to maintain the vehicle stock on hand by doing a full inspection on the vehicles before being sold (prepping) to the customer.
09-06-04-026Z2025-01-23. Service bulletin. This bulletin provides information on identifying Non-GM Engine Calibrations for Gasoline Engines using the Tech 2 or GDS 2.
PIT5962B2024-12-12. Service bulletin. This Preliminary information communicates a GM part number for reflective high temperature heat or insulating tape when repairing wiring harnesses.
21-NA-0432024-12-10. Service bulletin. This bulletin advises the dealers to maintain the vehicle stock on hand by doing a full inspection on the vehicles before being sold (prepping) to the customer.
20-NA-1322024-11-09. Service bulletin. This warranty administration bulletin provides policy information on the requirements for 12V battery testing and warranty replacements.
PIT5698E2024-10-25. Service bulletin. This Preliminary information communicates additional information on how a LIN bus operates and diagnostic tips when working on a LIN bus.