If your scan tool displays C0273, your vehicle’s Electronic Brake Control Module (EBCM) has detected an open circuit in the ABS delivery solenoid circuit inside the Hydraulic Control Unit (HCU).
The delivery solenoid—also known as the isolation solenoid—is responsible for controlling hydraulic brake pressure during Anti-lock Braking System (ABS) operation. When the EBCM detects a wheel beginning to lock during hard braking, it energizes the delivery solenoid to isolate hydraulic pressure while the return solenoid and pump motor regulate braking force. If the EBCM commands the delivery solenoid to operate but detects little or no current flow, it stores C0273 and typically disables the ABS, Traction Control (TCS), and Electronic Stability Control (ESC/StabiliTrak).
Unlike C0271, which indicates a general delivery solenoid circuit fault, C0273 specifically identifies an open electrical circuit in the delivery solenoid.
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 | C0273 |
| Description | ABS Delivery Solenoid Circuit Open |
| 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 | Open delivery solenoid winding, broken wiring, loose connectors, Hydraulic Control Unit failure, faulty EBCM |
| Typical Repair Cost | $100–2,000 |
What Does C0273 Mean?
The C0273 code indicates the Electronic Brake Control Module has detected an open circuit in the ABS delivery (isolation) solenoid circuit.
An open circuit occurs when electrical continuity is interrupted, preventing current from flowing through the delivery solenoid. When the EBCM commands the solenoid to energize but measures no current flow or improper circuit feedback, it determines that the circuit is open and stores C0273.
The EBCM continuously monitors:
- Solenoid resistance
- Circuit continuity
- Current flow
- Driver output
- Commanded versus actual operation
If the electrical path is interrupted anywhere between the EBCM and the delivery solenoid, the ABS system disables itself to prevent improper brake pressure control.
Symptoms of C0273
Drivers may notice:
- ABS warning light illuminated
- Traction Control warning light
- Electronic Stability Control warning
- Service Brake System message
- Service StabiliTrak message (GM vehicles)
- ABS disabled
- Traction Control unavailable
- Stability control disabled
- Stored C0273 diagnostic code
Conventional braking generally continues to operate normally.
Common Causes
Open Delivery Solenoid Coil
The delivery solenoid winding may fail internally due to:
- Broken winding
- Coil separation
- Internal electrical failure
This is one of the most common causes of C0273.
Broken Wiring
Inspect for:
- Broken conductors
- Pinched harnesses
- Chafed insulation
- Rodent damage
- Heat damage
Loose Electrical Connectors
Loose connector terminals may interrupt current flow.
Inspect connectors for:
- Poor terminal engagement
- Bent pins
- Connector damage
Corroded Connectors
Moisture intrusion may cause corrosion that creates an open circuit.
Hydraulic Control Unit Failure
Since the delivery solenoid is integrated into the Hydraulic Control Unit on many vehicles, an internal HCU failure may require replacement of the complete hydraulic assembly.
Faulty Electronic Brake Control Module
Although uncommon, an internal EBCM failure may prevent proper operation or monitoring of the delivery solenoid circuit.
How Serious Is C0273?
High.
With C0273 active, the Electronic Brake Control Module typically disables:
- Anti-lock Braking System
- Traction Control
- Electronic Stability Control
- Brake Assist
Normal hydraulic braking remains available, but emergency braking performance is reduced.
Can You Drive With C0273?
Yes—but with caution.
While standard braking remains functional:
- Wheels may lock during hard braking.
- Steering control under emergency braking is reduced.
- Stability control becomes unavailable.
- Traction control cannot intervene on slippery roads.
Repairs should be completed promptly.
How to Diagnose C0273
1. Scan the ABS Module
Use a professional scan tool capable of accessing manufacturer-specific ABS codes.
Check for related codes including:
- C0271
- C0272
- C0274
- C0275
- C0265
- U-series communication codes
2. Inspect Battery and Charging System
Verify:
- Battery voltage
- Charging voltage
- Ground integrity
Low system voltage can occasionally contribute to intermittent ABS electrical faults.
3. Inspect Wiring
Carefully inspect the harness between the EBCM and Hydraulic Control Unit for:
- Broken wires
- Chafed insulation
- Connector damage
- Corrosion
- Water intrusion
4. Measure Solenoid Resistance
Using manufacturer specifications, measure resistance across the delivery solenoid.
Infinite resistance generally confirms an open solenoid winding.
5. Perform Active Solenoid Testing
Many professional scan tools allow activation of individual ABS solenoids.
Verify:
- Audible clicking
- Current draw
- Circuit feedback
- Solenoid operation
Failure to activate usually confirms an open circuit.
6. Inspect the Hydraulic Control Unit
If wiring tests good but the solenoid measures open, replacement of the Hydraulic Control Unit may be necessary.
Some manufacturers allow replacement of the Electronic Brake Control Module separately, while others require replacement of the complete ABS hydraulic assembly.
Common Repairs
| Repair | Estimated Cost |
|---|---|
| Repair broken wiring | $100–350 |
| Clean or repair connectors | $50–150 |
| Repair ground connection | $50–150 |
| Replace Hydraulic Control Unit | $700–1,800 |
| Replace Electronic Brake Control Module | $800–2,000 |
| Module programming | $100–250 |
Common Diagnostic Mistakes
Technicians frequently:
- Replace wheel speed sensors unnecessarily.
- Replace the Hydraulic Control Unit before checking wiring.
- Ignore connector corrosion.
- Fail to measure delivery solenoid resistance.
- Overlook poor ground connections.
- Skip active solenoid testing.
Vehicles Commonly Affected
C0273 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
Similar delivery solenoid open-circuit faults are also found on other manufacturers using Bosch ABS hydraulic control systems.
How to Prevent C0273
Reduce the likelihood of C0273 by:
- Performing regular brake fluid service.
- Keeping ABS electrical connectors dry.
- Inspecting wiring during brake repairs.
- Repairing damaged harnesses promptly.
- Maintaining battery and charging system health.
- Addressing ABS warning lights immediately.
Frequently Asked Questions
What causes C0273?
The most common causes include an open delivery solenoid winding, broken wiring, corroded connectors, Hydraulic Control Unit failure, poor electrical connections, or an Electronic Brake Control Module fault.
Is C0273 serious?
Yes.
Although standard braking remains available, ABS, traction control, and stability control are disabled until the fault is repaired.
Does C0273 mean the Hydraulic Control Unit is bad?
Not necessarily.
The electrical circuit should always be tested before replacing the Hydraulic Control Unit because wiring and connector problems are common.
Can damaged wiring trigger C0273?
Absolutely.
Broken or corroded wiring is one of the leading causes of an open delivery solenoid circuit.
Does C0273 affect engine performance?
No.
The code only affects the vehicle’s braking and chassis safety systems.
Final Thoughts
The C0273 code indicates an open electrical circuit in the ABS delivery solenoid, preventing the Electronic Brake Control Module from properly controlling hydraulic brake pressure during anti-lock braking events. In many cases, the underlying issue is damaged wiring, connector corrosion, or an open solenoid winding rather than a failed Electronic Brake Control Module.
Proper diagnosis should begin with continuity testing, resistance measurements, and active solenoid testing before replacing expensive ABS components. Following a systematic troubleshooting process can 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:
- Complete OBD-II Code Guide: https://my.prostreetonline.com/dtc-obdii/
- Chassis (C) Code Library: https://my.prostreetonline.com/dtc-doctor/b-code-obd-ii-codes/
Related Articles
- C0271 Code Explained – ABS Delivery Solenoid Circuit
- C0272 Code Explained – ABS Return Solenoid Circuit
