C0268 Code Explained: Causes, Symptoms & ABS Pump Motor Circuit Low Voltage Fixes

C0268 Code Explained: Causes, Symptoms & ABS Pump Motor Circuit Low Voltage Fixes

If your scan tool displays C0268, your vehicle’s Electronic Brake Control Module (EBCM) has detected that the ABS hydraulic pump motor circuit voltage is lower than expected during operation.

The ABS pump motor is responsible for restoring hydraulic brake pressure after the ABS releases pressure to prevent wheel lockup. When the EBCM commands the pump motor to run, it monitors the circuit’s voltage and current. If the voltage drops below the manufacturer’s acceptable range, the module stores C0268 and typically disables the Anti-lock Braking System (ABS), Traction Control (TCS), and Electronic Stability Control (ESC/StabiliTrak).

Unlike C0267, which indicates an open circuit, C0268 points to insufficient voltage reaching the pump motor, often caused by a weak battery, charging system problem, high electrical resistance, damaged wiring, or a failing pump motor.

For additional chassis diagnostics and repair guides, visit our Complete OBD-II Trouble Code Guide:

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Quick Facts

ItemInformation
OBD-II CodeC0268
DescriptionABS Pump Motor Circuit Low Voltage
CategoryChassis (C) Codes
SystemAnti-lock Braking System (ABS)
Severity★★★★☆ High
Safe to Drive?Yes, but ABS and stability systems may be disabled
Common CausesWeak battery, charging system issues, high-resistance wiring, faulty relay, failing pump motor
Typical Repair Cost$75–1,700

What Does C0268 Mean?

The C0268 code indicates the Electronic Brake Control Module has detected lower-than-normal voltage in the ABS pump motor circuit.

During an ABS event, the pump motor draws a significant amount of electrical current. The EBCM expects battery voltage to remain within a specified operating range while the motor runs. If voltage falls below that threshold, the module assumes the pump cannot operate reliably and stores C0268.

Low voltage may be caused by:

  • Weak battery
  • Poor alternator output
  • Excessive wiring resistance
  • Corroded electrical connections
  • Poor ground connections
  • Worn pump motor brushes
  • Internal Electronic Brake Control Module failure

Once the fault is detected, the EBCM disables ABS-related safety functions until repairs are completed.

Symptoms of C0268

Drivers commonly notice:

  • ABS warning light illuminated
  • Traction Control light
  • StabiliTrak or ESC warning
  • Service Brake System message
  • Service StabiliTrak message (GM vehicles)
  • ABS disabled
  • Traction control unavailable
  • Stability control disabled
  • Stored C0268 diagnostic code

Conventional hydraulic braking typically continues to operate normally.

Common Causes

Weak Battery

A battery that cannot maintain proper voltage under load is one of the most common causes.

Cold weather often makes this problem worse.

Failing Alternator

Low charging voltage may prevent the ABS pump from receiving adequate power during operation.

Corroded Electrical Connections

Corrosion increases electrical resistance and causes excessive voltage drop.

Inspect:

  • ABS module connectors
  • Pump motor connector
  • Battery terminals
  • Ground connections

High Resistance Wiring

Damaged or partially broken wiring may still pass continuity tests while causing excessive voltage loss under load.

Faulty Pump Motor Relay

Burned relay contacts create additional resistance, reducing voltage delivered to the pump motor.

Worn ABS Pump Motor

As the pump motor ages, worn brushes or internal resistance can increase current demand and lower operating voltage.

Faulty Electronic Brake Control Module

Although less common, an internal EBCM fault may incorrectly detect low circuit voltage.

How Serious Is C0268?

High.

Without a properly functioning pump motor, several braking safety systems are disabled, including:

  • Anti-lock Braking System
  • Traction Control
  • Electronic Stability Control
  • Brake Assist

While the vehicle can still be driven, emergency braking performance is reduced, especially on wet, icy, or loose road surfaces.

Can You Drive With C0268?

Yes—but with caution.

The vehicle’s standard hydraulic brakes will continue to function, but:

  • Wheels may lock during hard braking.
  • Steering control during panic stops is reduced.
  • Stability control interventions are unavailable.
  • Stopping distances may increase on slippery roads.

Repairs should be completed promptly to restore full braking performance.

How to Diagnose C0268

1. Scan the ABS Module

Use a professional scan tool capable of reading manufacturer-specific ABS data.

Look for related codes including:

  • C0110
  • C0252
  • C0265
  • C0267
  • U-series communication codes

2. Test Battery Voltage

Check battery voltage with:

  • Engine off (approximately 12.6 volts)
  • Engine running (typically 13.5–14.8 volts)

Replace weak batteries before diagnosing additional ABS faults.

3. Inspect Charging System

Verify alternator output under electrical load.

Low charging voltage commonly triggers C0268.

4. Inspect Wiring and Grounds

Carefully inspect:

  • Battery terminals
  • ABS connectors
  • Ground straps
  • Wiring harnesses
  • Corrosion
  • Loose terminals

Perform a voltage drop test rather than relying only on continuity measurements.

5. Test the Pump Motor Relay

Inspect relay operation for:

  • High contact resistance
  • Intermittent operation
  • Burned terminals

Replace the relay if voltage loss is excessive.

6. Perform Active Pump Testing

Most professional scan tools allow activation of the ABS pump motor.

During testing, monitor:

  • Battery voltage
  • Pump current draw
  • Voltage at the pump motor
  • EBCM feedback

7. Test Pump Motor Current Draw

Excessive current draw often indicates internal motor wear that creates low-voltage conditions.

Common Repairs

RepairEstimated Cost
Replace battery$150–350
Replace alternator$400–900
Repair wiring$100–350
Clean electrical connections$50–150
Replace ABS relay$40–120
Replace ABS pump motor$500–1,200
Replace Electronic Brake Control Module$800–1,900

Common Diagnostic Mistakes

Technicians often:

  • Replace the ABS module before testing battery voltage.
  • Ignore charging system problems.
  • Overlook voltage drop across connectors.
  • Replace wheel speed sensors unnecessarily.
  • Skip relay testing.
  • Fail to load-test the battery.

Vehicles Commonly Affected

C0268 is frequently reported on:

  • Chevrolet Silverado
  • GMC Sierra
  • Chevrolet Tahoe
  • GMC Yukon
  • Chevrolet Avalanche
  • Chevrolet Suburban
  • Cadillac Escalade
  • Chevrolet Express
  • GMC Savana
  • Chevrolet TrailBlazer
  • GMC Envoy

The code is especially common on GM vehicles equipped with Bosch ABS systems, though similar low-voltage pump motor faults exist on other manufacturers.

How to Prevent C0268

Reduce the chances of C0268 by:

  • Replacing weak batteries before failure.
  • Keeping battery terminals clean.
  • Maintaining a healthy charging system.
  • Inspecting ABS wiring during brake service.
  • Protecting connectors from moisture and corrosion.
  • Repairing electrical faults before they worsen.

Frequently Asked Questions

What causes C0268?

The most common causes include a weak battery, failing alternator, corroded wiring, poor ground connections, faulty ABS relay, worn pump motor, or an Electronic Brake Control Module fault.

Is C0268 serious?

Yes.

Although normal braking remains available, the loss of ABS and stability control reduces braking performance during emergency situations.

Can a weak battery cause C0268?

Absolutely.

Low battery voltage is one of the most common causes of this code, particularly during cold weather.

Will replacing the battery fix C0268?

If low system voltage is the root cause, replacing the battery or repairing the charging system may resolve the issue. The circuit should always be tested before replacing ABS components.

Does C0268 affect engine performance?

No.

The code only impacts the vehicle’s braking and stability systems.

Final Thoughts

The C0268 code indicates that the ABS pump motor is receiving lower-than-expected voltage, preventing the Electronic Brake Control Module from operating the anti-lock braking system correctly. In many cases, the underlying problem is not the ABS module itself but rather a weak battery, charging system issue, corroded wiring, or excessive voltage drop within the electrical circuit.

Proper diagnosis should begin with testing battery and charging system performance before replacing expensive ABS components. Identifying voltage loss early can significantly reduce repair costs while restoring full ABS, traction control, and stability control functionality.

For additional chassis diagnostics and repair guides, browse our complete Chassis (C) OBD-II Code Library:

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