2023 GMC Sierra Electric Parking Brake and Flat Towing

The 2023 GMC Sierra 1500 uses an Electric Parking Brake (EPB): you apply it by pressing the EPB switch at a stop and release it with the ignition on, your foot on the brake and a press of the switch. Because the EPB can apply itself whenever it has power, GM's owner's manual requires you to disconnect and insulate the negative battery cable before dinghy (flat) towing the truck, and it does not allow dolly towing at all. Only 4WD trucks with a two-speed transfer case can be flat towed.

This guide covers the 2023 Sierra 1500 and follows the 2023 Sierra/Sierra Denali 1500 owner's manual. Sierra 2500HD/3500HD owners should check their own manual, available from GMC's owner manuals and guides page, since the towing rules differ by model and drivetrain.

How the 2023 Sierra's Electric Parking Brake Works

The EPB replaces the old foot pedal with a switch on the dash and electrically driven rear parking brakes. The owner's manual lays out the basic behavior:

• It can always be applied, even with the truck off, as long as there is enough electrical power.
• Without enough power it cannot be applied or released. A dead 12-volt battery leaves the brake wherever it was.
• It can apply by itself. The truck may set the EPB when stationary to check the system, or when another safety function asks for it. If you shift into Park on a hill, it may apply automatically and may not release from the switch until you shift out of Park.
• Avoid needless cycling. GM advises against repeated apply and release cycles to protect the battery.

Applying the EPB

1. Bring the truck to a complete stop.
2. Press the EPB switch momentarily.

The red parking brake light flashes, then stays on once the brake is fully applied. If you press and hold the switch while moving, the truck slows for as long as you hold it, and the EPB stays applied if you hold it until the truck stops.

Releasing the EPB

1. Turn the ignition on or to accessory mode.
2. Apply and hold the brake pedal.
3. Press the EPB switch momentarily.

The brake is released when the red light goes out. The EPB also releases on its own if the engine is running, the truck is in gear and you start to drive away. GM recommends gentle acceleration when this happens to save the parking brake linings.

EPB Warning Lights and Messages

What you see	What the owner's manual says
Red parking brake light on steady	EPB is applied
Red light flashing continuously	EPB is only partly applied or has a problem. Release and apply again. Do not drive while it flashes; see a dealer if it continues
Amber service parking brake light	Problem with the EPB. Other safety functions that use the EPB may also be degraded. See a dealer soon
Amber light on and you need to apply or release	Press and hold the switch until the red light stays on (apply) or goes out (release)
Either light stays on after a release attempt	See your dealer

A DIC message usually accompanies EPB faults. If the red brake system light is also on, that is a separate hydraulic brake warning. Our guide to why a Sierra brake warning light won't turn off covers that case.

Flat Towing (Dinghy Towing) a 2023 Sierra 1500

Owners get caught out here. The manual's warning is direct: if the battery stays connected, or the cable touches the post, the EPB may activate during towing and could cause a crash. Locked rear wheels at highway speed behind a motorhome can wreck tires and brakes and put everyone around you at risk.

Which Sierras Can Be Flat Towed

Drivetrain	Dinghy (four wheels down)	Dolly (two wheels up)
2WD	Not allowed; drivetrain damage not covered by warranty	Not allowed
4WD with single-speed transfer case	Not allowed	Not allowed
4WD with two-speed transfer case (has N and 4 LO)	Allowed, following GM's procedure	Not allowed

Dolly towing is ruled out for every 2023 Sierra 1500, front or rear wheels on the ground, 2WD or 4WD. If your truck can't be dinghy towed, it needs a flatbed or trailer. Check what your motorhome can pull too: see our 2023 Sierra 1500 towing capacity page for the truck's weight side of the equation.

GM's Dinghy Towing Procedure

This summarizes the owner's manual steps. Follow the manual itself for the exact wording for your truck.

1. Park the Sierra behind the tow vehicle, facing forward, on level ground.
2. Securely attach it to the tow vehicle.
3. Apply the parking brake and start the engine.
4. Shift the transfer case to N (Neutral) using the "Shifting Into N (Neutral)" steps for your transfer case control. On trucks with the button-type control, this means pressing 2H five times within 10 seconds, with the brake applied, until the N graphic flashes.
5. With the engine running, release the parking brake and confirm neutral: shift the transmission to D and then R. The truck should not move.
6. Shift the transmission to P (Park).
7. Release the parking brake.
8. Turn the truck off.
9. Turn the ignition on without starting the engine: foot off the brake, press and hold ENGINE START/STOP for five seconds until the green light on the button comes on.
10. Disconnect the negative (-) battery cable and cover both the cable end and the battery post with non-conductive material.
11. Move the steering wheel to make sure the column is unlocked.
12. On column-shift trucks, verify the transmission is in P.
13. Keep the remote key outside the truck and lock the doors manually with the key.

GM warns that shifting the transfer case to Neutral lets the truck roll even in Park, so set the parking brake and block the wheels before step 4.

Disconnecting the Battery Correctly

The manual gives two versions of the negative cable removal:

• Trucks with Stop/Start (AGM battery): remove the negative cable nut at the battery sensor connection, lift the cable off the sensor stud, and cover the cable terminal, sensor stud and battery post.
• Trucks without Stop/Start: loosen the negative cable nut, remove the clamp from the post, and cover the clamp and post.

Be aware of one conflict in the manual. The general battery section says to turn the ignition off before removing the cable and warns that disconnecting with the ignition on or during Retained Accessory Power permanently discharges the OnStar backup battery. The dinghy towing steps, however, have you turn the ignition on before disconnecting. Follow the dinghy procedure for towing, and ask your dealer about the OnStar backup battery if you flat tow often. When reconnecting, use the original nut and tighten it by hand tool only, not an impact gun.

Many RV owners install a battery disconnect switch in the negative cable so they don't have to unbolt it every trip. If you go that route, make sure the switch fully isolates the truck's electrical system. Any tow wiring that feeds power into the Sierra (a charge line for the towed vehicle's battery, for example) can also power the EPB, so have a qualified installer check the setup. The owner's manual procedure is written around removing and covering the negative cable.

Unhooking After the Tow

1. Park on level ground and block the wheels.
2. Reconnect the negative battery cable.
3. Turn the ignition on without starting the engine (foot off the brake, hold ENGINE START/STOP for five seconds).
4. Set the parking brake.
5. Disconnect from the tow vehicle.
6. Start the engine.
7. Shift the transmission to N (Neutral).
8. Shift the transfer case to 2H and wait for the cluster light to stop flashing.
9. Confirm the shift: put the transmission in D, then R. The truck should move this time.
10. Shift to P and turn off the ignition.
11. Release the parking brake and remove the wheel blocks.
12. Reset any lost presets. The outside temperature display may read 32°F until it relearns.

After reconnecting the battery, some functions may need to relearn. See resetting the Sierra parking brake after a battery disconnect if the EPB warning stays on.

When the Truck Is Disabled: Flatbed Towing and a Dead Battery

For a breakdown tow, GM recommends a flatbed. The truck must be in N (Neutral) with the EPB released before it is loaded, and GM warns against moving it with the drive-axle tires on the ground.

The catch is power. With no 12-volt power the EPB cannot be released and, on trucks with an electronic shifter, the transmission cannot be put in Neutral. The manual's order of operations:

1. Try to jump start the truck with a known good 12-volt battery.
2. If it starts, shift to Neutral (on electronic-shifter trucks, use Car Wash Mode) and release the EPB.
3. If jump starting fails, the truck will not roll. The tow operator must use tire skates or dollies under the non-rolling tires. Dragging the truck onto the bed causes damage GM does not cover under warranty.

Tell the tow company up front that the truck has an electric parking brake, especially if the battery is dead.

Electric Brake Boost and ABS on the 2023 Sierra

The original version of this page described the Sierra's "electronic brake" in general terms. The owner's manual describes two systems:

• Electric brake boost (if equipped): the hydraulic brake circuits are electronically controlled when you press the pedal. The system runs self-tests and shuts down a few minutes after you turn the truck off; you may hear it during this time. Pressing the pedal during the tests or while the system is off can feel different in effort and travel. GM says this is normal. If the red brake system light comes on while driving, the brake pedal may be harder to push or go closer to the floor, stopping may take longer, and vehicle speed may be limited. GM says to pull off safely and have the truck towed if the light stays on.
• ABS: runs a check when you first drive off, which can cause a brief motor or clicking noise and slight pedal movement. Hold firm pressure in a panic stop and let ABS work; don't pump the pedal.

The EPB is also used by other safety functions. Hill Start Assist, for example, applies the EPB if you stay stopped on a grade for more than a few minutes without pressing the accelerator. See our overview of GMC Brake Assist for how the stability systems use the brakes.

Maintenance Notes From the Owner's Manual

• Brake fluid: GM specifies GM-approved DOT 4 fluid from a clean, sealed container.
• Brake pad life system: the Driver Information Center shows the estimated pad life for each axle. The system detects pad replacement on its own when significantly worn pads are replaced and new wear sensors are fitted, and it can also be reset from the DIC. Replace pads as complete axle sets.
• Rear brake work: on vehicles with an electric parking brake, the parking brake usually has to be retracted with a scan tool service function before rear brake work. Our Acadia parking brake service mode guide explains the principle; confirm the Sierra procedure in GM service information for your VIN.
• Battery health: because the EPB won't release without power, a weak battery affects more than starting. Keep the battery tested, and use the AGM setting on your charger if the truck has Stop/Start.

For general parking brake care across GMC models, including older pedal-type systems, see the GMC parking brake guide.

Frequently Asked Questions

Can you flat tow a 2023 GMC Sierra 1500?

Only if it is a 4WD truck with a two-speed transfer case that has N (Neutral) and 4 LO. 2WD trucks and trucks with a single-speed transfer case must not be towed with all four wheels down, according to the owner's manual.

Why does GM say to disconnect the battery before flat towing?

The electric parking brake can apply whenever it has power. The manual warns that if the negative cable is left connected, or touches the post, the EPB may activate during towing and could cause a crash.

Can a 2023 Sierra be towed on a dolly?

No. The owner's manual does not allow dolly towing with either the front or rear tires on the ground, for 2WD or 4WD trucks, whatever the transfer case.

How do I release the parking brake if the battery is dead?

It can't be released without electrical power. Jump start the truck with a good 12-volt battery, then release the EPB with the ignition on, foot on the brake and a press of the switch. If that fails, the truck must be moved with tire skates or dollies under the locked wheels.

What does a flashing red parking brake light mean?

The EPB is only partly applied or has a fault. Release it and apply it again. If the light keeps flashing, don't drive the truck; GM says to see a dealer.