If your scan tool displays C0269, your vehicle’s Electronic Brake Control Module (EBCM) has detected that the ABS hydraulic pump motor circuit voltage is higher than expected while the pump motor is operating.
The ABS pump motor restores brake pressure after the Anti-lock Braking System releases hydraulic pressure to prevent wheel lockup. During every ABS event, the EBCM continuously monitors voltage, current, and relay feedback. If the module detects excessive voltage in the pump motor circuit, it stores C0269 and usually disables the ABS, Traction Control (TCS), and Electronic Stability Control (ESC/StabiliTrak) systems to prevent component damage.
Unlike C0268, which indicates low voltage, C0269 points to an over-voltage condition, often caused by an overcharging alternator, short-to-voltage wiring fault, defective relay, poor ground reference, or an internal Electronic Brake Control Module failure.
For additional chassis diagnostics and repair guides, visit our Complete OBD-II Trouble Code Guide:
https://my.prostreetonline.com/dtc-obdii
Quick Facts
| Item | Information |
|---|---|
| OBD-II Code | C0269 |
| Description | ABS Pump Motor Circuit High Voltage |
| Category | Chassis (C) Codes |
| System | Anti-lock Braking System (ABS) |
| Severity | ★★★★☆ High |
| Safe to Drive? | Yes, but ABS and stability systems may be disabled |
| Common Causes | Overcharging alternator, short to battery voltage, faulty relay, damaged wiring, poor ground, EBCM failure |
| Typical Repair Cost | $75–1,900 |
What Does C0269 Mean?
The C0269 code indicates the Electronic Brake Control Module (EBCM) has detected higher-than-normal voltage in the ABS pump motor circuit.
The ABS pump motor normally operates near vehicle charging system voltage. If voltage exceeds the manufacturer’s calibrated limit, the EBCM determines that the circuit is no longer operating safely and stores C0269.
Common causes of excessive voltage include:
- Overcharging alternator
- Failed voltage regulator
- Short to battery voltage
- High-resistance ground circuit
- Faulty pump motor relay
- Damaged wiring harness
- Internal Electronic Brake Control Module failure
Because excessive voltage can damage sensitive electronic components, the EBCM typically disables ABS operation until the fault is repaired.
Symptoms of C0269
Drivers may experience:
- ABS warning light illuminated
- Traction Control warning light
- StabiliTrak or ESC warning
- Service Brake System message
- Service StabiliTrak message (GM vehicles)
- ABS disabled
- Traction Control disabled
- Electronic Stability Control unavailable
- Stored C0269 diagnostic code
Normal braking performance generally remains unaffected during routine driving.
Common Causes
Overcharging Alternator
A faulty voltage regulator may allow charging voltage to exceed safe operating limits.
Overcharging commonly affects multiple vehicle systems simultaneously.
Faulty Voltage Regulator
Many modern alternators contain an internal voltage regulator.
Failure can produce charging voltages well above specification.
Short to Battery Voltage
Damaged wiring may allow constant battery voltage to reach the ABS pump motor circuit.
Inspect for:
- Pinched wiring
- Melted insulation
- Previous repair damage
- Harness abrasion
Faulty Pump Motor Relay
Relay contacts that stick closed or develop internal faults may produce incorrect voltage readings.
Poor Ground Connection
A weak or corroded ground may create false high-voltage readings at the Electronic Brake Control Module.
Ground problems frequently produce intermittent ABS faults.
Electronic Brake Control Module Failure
Although less common, an internal EBCM fault may incorrectly report excessive circuit voltage.
How Serious Is C0269?
High.
When C0269 is active, the vehicle usually loses:
- Anti-lock Braking System (ABS)
- Traction Control
- Electronic Stability Control
- Brake Assist
Although standard hydraulic brakes continue to function, emergency braking performance and vehicle stability are significantly reduced.
Can You Drive With C0269?
Yes—but with caution.
You can usually continue driving because normal braking remains functional.
However:
- Wheels may lock during hard braking.
- Vehicle stability is reduced.
- Traction control cannot assist on slippery roads.
- Emergency stopping distances may increase.
The underlying electrical problem should be repaired promptly.
How to Diagnose C0269
1. Scan the ABS Module
Use a professional scan tool capable of reading manufacturer-specific ABS codes.
Check for additional codes including:
2. Test Charging Voltage
Measure charging voltage at the battery.
Typical charging voltage should remain between:
- 13.5–14.8 volts
Charging voltage exceeding approximately 15 volts often indicates an alternator or voltage regulator problem.
3. Inspect Battery Condition
A damaged battery can occasionally contribute to unstable charging system voltage.
Verify:
- Battery health
- Terminal condition
- Cable integrity
4. Inspect Wiring
Inspect the ABS wiring harness for:
- Shorts to battery voltage
- Melted insulation
- Pinched harnesses
- Corroded connectors
- Moisture intrusion
5. Check Ground Circuits
Inspect:
- Battery grounds
- Chassis grounds
- Engine grounds
- EBCM grounds
High-resistance grounds frequently create inaccurate voltage readings.
6. Test the Pump Motor Relay
Verify proper relay operation.
Inspect for:
- Stuck contacts
- Burned terminals
- Excessive resistance
Replace faulty relays as needed.
7. Perform Active Pump Motor Testing
Most professional scan tools allow activation of the ABS pump motor.
Monitor:
- Supply voltage
- Pump current draw
- Relay feedback
- EBCM data
Compare measured voltage with manufacturer specifications.
Common Repairs
| Repair | Estimated Cost |
|---|---|
| Replace voltage regulator | $200–600 |
| Replace alternator | $450–950 |
| Repair wiring | $100–350 |
| Clean or repair grounds | $50–150 |
| Replace pump motor relay | $40–120 |
| Replace ABS pump motor | $500–1,200 |
| Replace Electronic Brake Control Module | $800–2,000 |
Common Diagnostic Mistakes
Technicians commonly:
- Replace the ABS module before checking charging voltage.
- Ignore alternator overcharging.
- Fail to inspect ground circuits.
- Replace wheel speed sensors unnecessarily.
- Overlook wiring shorts.
- Skip relay testing.
Vehicles Commonly Affected
C0269 is commonly 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 particularly common on GM trucks and SUVs equipped with Bosch ABS systems, although similar high-voltage pump motor faults may appear on other manufacturers.
How to Prevent C0269
Reduce the likelihood of C0269 by:
- Maintaining the charging system.
- Replacing failing alternators promptly.
- Inspecting battery cables regularly.
- Cleaning chassis and engine ground connections.
- Protecting ABS wiring from heat and abrasion.
- Repairing electrical problems before they damage ABS components.
Frequently Asked Questions
What causes C0269?
The most common causes include an overcharging alternator, faulty voltage regulator, wiring shorted to battery voltage, poor grounds, defective relay, or an Electronic Brake Control Module fault.
Is C0269 serious?
Yes.
The loss of ABS, traction control, and stability control reduces vehicle safety during emergency braking and low-traction conditions.
Can an alternator cause C0269?
Absolutely.
An alternator producing excessive charging voltage is one of the leading causes of this code.
Will replacing the ABS module fix C0269?
Not usually.
The charging system and wiring should always be tested before replacing expensive ABS components.
Does C0269 affect engine performance?
No.
The code only affects the vehicle’s braking and chassis safety systems.
Final Thoughts
The C0269 code indicates that the Electronic Brake Control Module has detected excessive voltage in the ABS pump motor circuit. In many cases, the underlying cause is an overcharging alternator, faulty voltage regulator, wiring fault, or poor ground rather than a failed ABS module. Because excessive voltage can damage sensitive electronic components, the EBCM disables ABS, traction control, and stability control until the problem is corrected.
Proper diagnosis should begin with a complete charging system inspection before replacing expensive brake system components. Identifying the root electrical fault early can prevent unnecessary repairs while restoring full ABS functionality.
For additional chassis diagnostics and repair guides, browse our complete Chassis (C) OBD-II Code Library:
- Complete OBD-II Code Guide: https://my.prostreetonline.com/dtc-obdii/
- Chassis (B) Code Library: https://my.prostreetonline.com/dtc-doctor/b-code-obd-ii-codes/
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