P25A2: Brake control module has asked for the check engine light

Brake system control module requested MIL illumination

Severity: Inspect soon

P25A2 is a request from the brake control module, and GM bulletins pair it with a spongy pedal or loss of brake assist, so have the brakes diagnosed soon even if they feel normal.

It gets more serious if:

Stop: Stop driving and arrange a tow if the brake pedal feels spongy, hard or travels further than usual, or a brake or Service Brake System warning appears.

Safety-critical system: explanation only, no DIY steps. Source: how we rate severity

P25A2 in short

P25A2 means the brake control module found a fault of its own and asked the engine computer to turn on the check engine light. On GM trucks and SUVs, bulletins point to low voltage, wiring or a brake module fault, sometimes with a spongy or hard pedal. Have the brakes checked soon; stop driving if the pedal feels different.

Some faults the brake control module finds can affect emissions or drivability, so it asks the engine computer to light the check engine lamp and P25A2 is stored. The code itself does not say what is wrong; the real fault is in the brake module’s own codes.

On 2021–2026 GM trucks and SUVs, GM tells dealers that when the brake module sets P0606 with P0562 and/or P25A2, they should check for low voltage, wiring, terminal and communication problems before replacing parts. On 2019–2020 trucks it has appeared with loss of brake assist and a pedal that feels different, and on the 2023 Colorado and Canyon with a spongy pedal.

Other makes use the code too. On the 2020 Cadillac CT4 and CT5 it appeared with a front camera fault and driver-assist messages, and Land Rover issued a bulletin for it on 2015 Range Rover and Range Rover Sport with the 3.0L supercharged V6.

Most likely causes

Cause 1: Low voltage, wiring or terminal problems at the brake module
Supported by vehicle data
Why it ranks here
GM PIT6522 covers 2021–2026 trucks and SUVs and tells dealers to check voltage, wiring, terminals and communication before replacing parts when P25A2 sets with P0606 and P0562.
What would change this
Rises if the battery tests weak, P0562 is stored, or connectors at the brake module show corrosion. Falls if power and wiring test good.
Cause 2: Brake control module or brake hydraulic fault
Supported by vehicle data
Why it ranks here
GM bulletins 20NA073 (2019–2020) and PIT6012 (2023 Colorado, Canyon) pair P25A2 with brake module codes, loss of brake assist and a spongy pedal.
What would change this
Rises if brake C-codes are stored and the pedal feels different. Falls if only P25A2 is stored and the brakes work normally.
How to test the brake system control module (abs module)
Cause 3: Front camera fault passed on through the brake system (2020 Cadillac CT4, CT5)
Supported by vehicle data
Why it ranks here
GM PIC6404 lists P25A2 with U0265 and U0566 and driver-assist messages, and replaces the front view camera for frequent cases.
What would change this
Rises on a CT4 or CT5 with Service Driver Assist or Steering Assist Reduced messages. Falls on other models.
Cause 4: Any other brake system fault that triggers the request
Possible — needs testing
Why it ranks here
P25A2 is a secondary code, so the cause is whatever the brake module itself has stored; it ranks last because it needs the brake module codes to narrow it down.
What would change this
Rises once the brake module’s own codes point at a sensor or circuit. Falls if those codes match a cause above.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

Step 1: Scan the brake control module and all other modules, and note every code stored with P25A2.
Low riskTool: scan tool that reads the brake module
- IfP0562 or P0606 is stored with it
  It meansCheck the power supply first.
  Go to step 2
- IfBrake C-codes are stored
  It meansThe brake module or hydraulics need professional diagnosis.
  Points to: Brake control module or brake hydraulic fault
- IfU0265 or U0566 with driver-assist messages on a CT4 or CT5
  It meansThe front camera bulletin applies.
  Points to: Front camera fault passed on through the brake system (2020 Cadillac CT4, CT5)
- IfOnly P25A2 is stored
  It meansThe brake module request needs a professional check.
  Points to: Any other brake system fault that triggers the request
Step 2: Test the battery and charging voltage, and check that the battery cables and grounds are clean and tight.
Low riskTool: battery tester or multimeter
- IfThe battery is weak or a connection is poor
  It meansLow voltage may be setting the brake module codes.
  Points to: Low voltage, wiring or terminal problems at the brake module
- IfBattery and charging test good
  It meansThe brake system needs professional diagnosis.
  Go to step 3
Step 3: Have a shop diagnose the brake system, including the brake module wiring and terminals, using the brake module codes and any bulletin for your vehicle.
Best left to a shop
Warning:Brakes are safety-critical. Do not work on the brake module or hydraulics yourself.
- IfWiring, terminal or communication faults are found
  It meansRepair them before replacing the module.
  Points to: Low voltage, wiring or terminal problems at the brake module
- IfThe brake module or hydraulic unit is faulty
  It meansRepair as the bulletin or service information directs.
  Points to: Brake control module or brake hydraulic fault

Symptoms

Check engine light with brakes that still feel normal
Spongy brake pedal Gets more serious: stop and have it checked.
Hard pedal or loss of brake assist Gets more serious: stop and have it checked.
Service Brake System, Service Driver Assist or Steering Assist Reduced message Gets more serious: stop and have it checked.

How to fix

This is a safety-critical system, so we explain the code but don't give repair steps. Have it inspected by a qualified technician.

Parts and cost context

Brake system control module (ABS module):GM asks dealers to rule out low voltage, wiring and terminals before replacing the brake module. Labour varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Chevrolet

2019–2026 · Silverado 1500
Supported by vehicle data
GM bulletins tie P25A2 on the Silverado to the brake module with P0606 and P0562, low voltage and loss of brake assist. Check the battery first, then have the brakes diagnosed. Whether the bulletin is still current is not verified.

PIT6522Status unverified
K160 brake module sets P0606 with P0562 and/or P25A2
2021–2026sierra-1500, yukon, acadia, canyon · issued June 10, 2026 · NHTSA 11033987
Check for low voltage, wiring, terminal and communication problems before replacing parts. Also covers Chevrolet Tahoe.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
20NA073Status unverified
Loss of brake assist, P0606 with brake codes or P25A2
2019–2020sierra-1500 · issued September 22, 2020 · NHTSA 10181688
Brake pedal travel and feel may change; also covers Silverado 1500 and other GM models.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
PIT6012Status unverified
Check engine light, spongy brake pedal, C05D3 and P25A2
2023colorado · issued May 5, 2023 · NHTSA 10237644
Diagnostic information for a spongy pedal with C05D3 and P25A2. Also covers GMC Canyon.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

GMC

2019–2026 · Sierra 1500
Supported by vehicle data
Same GM brake module bulletins as the Silverado. Whether the bulletin is still current is not verified.

PIT6522Status unverified
K160 brake module sets P0606 with P0562 and/or P25A2
2021–2026sierra-1500, yukon, acadia, canyon · issued June 10, 2026 · NHTSA 11033987
Check for low voltage, wiring, terminal and communication problems before replacing parts. Also covers Chevrolet Tahoe.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
20NA073Status unverified
Loss of brake assist, P0606 with brake codes or P25A2
2019–2020sierra-1500 · issued September 22, 2020 · NHTSA 10181688
Brake pedal travel and feel may change; also covers Silverado 1500 and other GM models.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

All ABS, traction and stability control codes

P25A2 questions

Why does a brake problem turn on the check engine light?

Some brake module faults affect emissions or drivability, so the brake module asks the engine computer to light the lamp. The real fault is in the brake module’s own codes.

Is it safe to drive with P25A2?

Only gently and only to a shop if the brakes feel normal. Stop driving if the pedal feels spongy or hard or a brake warning appears.

Sources and review

P25A2 OBD-II code — Kelley Blue Book
GM PIT6012: check engine light, spongy brake pedal, C05D3 and P25A2 (2023 Colorado, Canyon) — General Motors / NHTSA , May 5, 2023
GM bulletin 20NA073: loss of brake assist, P0606 with C-codes or P25A2 (2019–2020 Silverado, Sierra and others) — General Motors / NHTSA , September 22, 2020
GM PIT6522: K160 brake module sets P0606 with P0562 and/or P25A2 (2021–2026 trucks and SUVs) — General Motors / NHTSA , June 10, 2026
GM PIC6404: Service Driver Assist, Steering Assist Reduced, MIL with P25A2, U0265, U0566 (2020 CT4, CT5) — General Motors / NHTSA , February 6, 2020

Last reviewed: October 15, 2026
Written by: Saurabh K.
Editorial review: Pending
Technician review: Technician review pending

This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error

Severity: Inspect soon

Most likely causes

Cause 1: Low voltage, wiring or terminal problems at the brake module

Cause 2: Brake control module or brake hydraulic fault

Cause 3: Front camera fault passed on through the brake system (2020 Cadillac CT4, CT5)

Cause 4: Any other brake system fault that triggers the request

What to test first

Step 1: Scan the brake control module and all other modules, and note every code stored with P25A2.

Step 2: Test the battery and charging voltage, and check that the battery cables and grounds are clean and tight.

Step 3: Have a shop diagnose the brake system, including the brake module wiring and terminals, using the brake module codes and any bulletin for your vehicle.