By iCarsoft Official Store Technical Team, Automotive Diagnostics Editors · Updated September 27, 2026 · Technical sources checked
Quick Answer
In the cited GM application, C0024 identifies the brake pedal simulator separating solenoid valve. Confirm the VIN, full fault text and current service procedure. The code does not prove that the valve or complete brake assembly needs replacement. A pedal change or loss of assistance requires immediate safety assessment.
What Does the C0024 Code Mean?
GM bulletin 20-NA-073 lists C0024 as Brake Pedal Simulator Separating Solenoid Valve for its specified applications. This guide uses that GM meaning; it does not establish a universal definition for every vehicle. The full fault record determines the test branch.
An electronically controlled braking system can use a pedal simulator to provide the intended pedal response while other elements manage brake pressure. Identify the installed arrangement before applying a test. The simulator valve is not interchangeable with a wheel-speed sensor, stop-lamp switch or conventional vacuum-booster component. A familiar-sounding scan description does not identify an accessible standalone replacement part.
The important distinction is between a reported valve-related fault and the actual state of the brake system. Code wording, pedal behavior, controller supply and related records should be considered together. A scan tool may display a command or status, but that does not prove physical valve movement or pressure at a wheel. Use the prescribed functional and electrical checks to resolve that gap.
GM bulletin 20-NA-073, September 2020, includes selected 2019–2020 vehicles and names C0024 among faults associated with altered pedal response or reduced assist. It describes a calibration-related condition and a BSCM programming path. Those statements apply only after the model, equipment and condition match; the bulletin is not a recall lookup or a universal instruction to reflash any vehicle with C0024.
Record when the warning appeared relative to brake work. Record whether the pedal changed before or after the warning, whether the code is current, and what was disconnected or programmed. Distinguish historical records from current safety problems. Address an unsafe physical condition before attempting software or code-clearing experiments.
Save the full module wording and suffix before clearing; they can change the test path.
Separate C0024 from adjacent fault families
| Code | General description | Key distinction |
|---|---|---|
| C0024 | GM simulator separating solenoid valve | Use the exact application and full fault record. |
| C0022 | Brake Booster Solenoid in the NHTSA reference | Different label; not a substitute test procedure. |
| C0021 | Brake Booster Performance in the NHTSA reference | Performance wording must match the reporting module. |
| C0023 | Stop Lamp Control in the NHTSA reference | Lamp/control path is distinct from simulator diagnosis. |
Record the complete C0024 description. Use the exact module, suffix and OEM procedure to select the test path.
C0024 Symptoms and Likely Causes
Record C0024 symptoms and fault status; symptoms alone cannot identify a failed part.
Check whether companion faults share a proven cause.
Longer travel, unusual softness or increased pedal effort requires prompt professional assessment. Do not treat a displayed valve code as reassurance that hydraulic braking is normal.
Record the exact dashboard messages and when they appear. Different warnings can represent different levels of assistance or braking-system availability; follow the owner manual.
Other brake-control or supply faults may accompany the event. Their status and order can help choose the appropriate diagnostic branch without proving several separate failed parts.
A stored event after a previous warning still deserves documentation. A warning that disappeared after a restart does not establish that the original cause or any unsafe pedal condition has been corrected.
Practical cause-checking order
- Identify the full event: Confirm that the vehicle actually uses the cited GM simulator-valve description. Retrieve the complete subfault and controller identification before discussing a replacement.
- Check the connections: Check accessible connectors and harness routing around components disturbed during recent work, using the required isolation procedure. A visual inspection can guide testing but cannot certify the internal valve.
- Test the relevant circuit: Verify controller power and return paths according to the applicable diagram. Do not use an arbitrary resistance value or direct battery jumper to test an electronically controlled brake valve.
- Check the physical counterpart: Have a qualified technician assess pedal and hydraulic operation using the correct brake-system procedure. A scan status and a physical measurement answer different questions.
- Confirm the final repair branch: Check current OEM bulletin and calibration applicability. If a programming path applies, use the approved equipment and prerequisites; otherwise continue the specific diagnostic tree rather than assuming software is the cause.
Did C0024 appear after recent brake-control, battery, pedal or hydraulic-system work? Recheck the documented connections, parts and setup steps affected by that work. Record battery and software history; a post-repair code does not prove the new part is defective.
How Serious Is C0024, and Can You Drive?
Arrange prompt brake diagnosis and follow the owner manual. Do not assume ABS or stability assistance remains available. Abnormal pedal effort, pulling, fluid loss, dragging or a red brake warning requires stopping safely and arranging recovery. The code cannot establish a safe driving distance.
Record brake warnings, pedal changes, fluid loss and recent service. Do not induce wheel slip or emergency braking to test assistance on public roads; warning-state assessment comes before any functional verification.
Stop and arrange a tow if braking changes, pedal effort or travel is abnormal, a wheel drags, fluid leaks or a red brake warning appears.
Brake systems may retain pressure or operate electrically after the engine stops. Follow the exact shutdown and pressure-release procedure before opening anything. Support a raised vehicle on approved equipment, keep hands away from moving parts, and do not energize unidentified brake circuits with jumper wires. A public-road emergency stop is not an acceptable diagnostic experiment.
How to Diagnose C0024 in the Right Order
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Save the full GM brake-control fault record
Read the brake controller and related modules, preserving the complete C0024 description, status, suffix and available event data. Record the actual warning messages, pedal symptoms and recent battery or brake work. Do not clear the code merely to see whether it returns, and do not attempt a road test when assistance or pedal operation is abnormal.
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Confirm the exact vehicle and valve description
Use the VIN, model year, equipment and controller identification to obtain the current diagnostic procedure. Confirm that the scanned description matches the GM simulator-valve meaning used here. Check the full application table and any superseding information before using bulletin 20-NA-073. A similar model name or shared base code alone is insufficient evidence of applicability.
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Assess braking safety before invasive tests
With the vehicle safely secured, have the brake system assessed for the reported pedal behavior, warning state and visible fluid problems. Follow the manufacturer shutdown and pressure-release instructions before accessing an energized or pressurized assembly. Do not open a hydraulic line, disconnect a live actuator or command a brake function as an informal way to locate the fault.
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Check supplies, connectors and disturbed work
Inspect the connections and routing affected by recent service, then perform the specified supply, return and circuit checks at approved test points. Record the result and required operating condition together. A voltage reading without the prescribed load or state may not answer the diagnostic question. Keep physical evidence separate from a commanded value displayed on the scanner.
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Separate a supported calibration path from hardware diagnosis
If the current OEM procedure identifies an applicable calibration issue, document that match and arrange the approved programming process. If the vehicle does not match, or the prescribed check still fails, continue normal circuit and component diagnosis. Do not infer programming support from a scanner product name or use an available menu as proof that the required OEM operation is supported.
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Verify pedal response and the complete repair
After the demonstrated cause is corrected, complete the specified setup and any required hydraulic procedures. Confirm normal pedal and braking operation before an authorized functional check. Save a final scan and record whether the original conditions were reproduced safely and the fault remained absent. A cleared dashboard warning by itself is not a complete brake-system release check.
Specifications are vehicle-specific. Use the exact VIN specifications, approved test points and required operating state. No generic value or drive cycle can replace the applicable procedure. Manufacturer examples here do not establish specifications for other applications.
C0024 Repairs and Cost Planning
A C0024 repair must address the demonstrated failure. Do not replace an assembly from the code alone.
Recheck installation and required setup after repair. Ask whether the proposed part is individually serviceable and whether the estimate includes the required setup, fluid handling and verification. A broad brake assembly estimate should identify the failed test, not merely repeat the code description. A software recommendation should identify the applicable calibration or service procedure and explain why it matches this vehicle.
Ask which measurement supports each proposed repair.
Authorize diagnosis before parts while the cause remains uncertain.
| Possible path | Quote basis |
|---|---|
| Repair the connector or harness after a documented circuit failure | VIN-specific quote |
| Correct the demonstrated physical or installation fault | VIN-specific quote |
| Replace only the component that fails its prescribed test | VIN-specific quote |
| Complete required setup and safe functional verification | VIN-specific quote |
These are alternatives, not cumulative charges. Request a VIN-specific breakdown of diagnosis, parts, labor, fluids, taxes, setup and verification. Ask which test supports the repair and whether warranty applies.
Using iCarsoft CR Eagle P for C0024
On a supported vehicle, iCarsoft CR Eagle P can save accessible faults, available freeze frame, live data and diagnostic reports. Preserve the C0024 evidence before clearing.
Compare available brake-controller records before and after repair. The report supports diagnosis but cannot replace the OEM physical and functional checks.
Preserve the GM brake-pedal simulator valve diagnosis evidence
iCarsoft CR Eagle P
Review supported codes and relevant live data together. Confirm the exact VIN, controller access, PIDs and any requested active test with iCarsoft before purchase; generic product capabilities do not guarantee a C0024-specific function.
Check current CR Eagle P price and availabilityCheck CR Eagle P compatibility by VINConfirm VIN-specific brake-controller access and any requested function with iCarsoft. Follow OEM prerequisites and stop for abnormal operation.
Know the measurement boundary. Scan data describes ECU-provided information; it does not directly prove the physical condition of the GM brake-pedal simulator valve diagnosis. Where required, use the specified multimeter, oscilloscope and approved brake-system test equipment and compare reported values with the relevant measured evidence.
Verify the C0024 Repair
Verify connections, setup and controller supply after repair. Save findings before clearing erasable records. Battery disconnection is not a repair.
Run the applicable confirmation checks in a safe setting. Compare original and current brake-controller conditions and inspect related faults. One clean restart does not prove the complete verification passed.
Compare baseline and final scans, required setup and fault confirmation. Record whether the original event returned.
If C0024 returns, compare its suffix, status, failure order and operating conditions with the saved baseline before replacing another part. Revisit the failed branch and inspect anything disturbed. Confirm the prescribed brake-system verification separately from code clearing.
Stored and Active brake-control faults require different decisions. Preserve the original record and follow the OEM confirmation procedure. A cleared display does not prove restored assistance or safe braking.
Related GM Brake-Pedal Simulator Valve Diagnosis Code Guides
Use each related code's own diagnostic procedure.
C0024 Frequently Asked Questions
Does C0024 always mean the simulator valve must be replaced?
No. This guide uses the GM simulator-valve meaning documented in the cited bulletin. Confirm the full OEM wording and VIN application first. A valve-related record does not alone prove a failed standalone valve or complete assembly; the applicable circuit, functional and calibration checks determine the repair path.
What should I check first for C0024?
Save every module's codes and freeze frame before clearing. Confirm the full definition, suffix and VIN architecture. Then inspect recent brake-control, battery, pedal or hydraulic-system work, connectors and shared supplies. Those facts determine whether the next test needs the specified multimeter, oscilloscope and approved brake-system test equipment or a manufacturer-specific functional procedure.
Can I drive with the C0024 code?
Arrange prompt brake diagnosis and follow the owner manual. Do not assume ABS or stability assistance remains available. Abnormal pedal effort, pulling, fluid loss, dragging or a red brake warning requires stopping safely and arranging recovery. The code cannot establish a safe driving distance.
Why did C0024 return after a part was replaced?
A returning C0024 may be a different subfault, an unresolved external condition, an incomplete required setup or a condition outside the bulletin. Save the new record and compare it with the original. Do not repeatedly program a controller or replace a second assembly without establishing why the previous repair did not meet the prescribed confirmation checks.
What should a C0024 repair estimate include?
Request failed-test evidence and itemized diagnosis, parts, labor, setup and verification costs. The code cannot determine the price.
Can CR Eagle P diagnose and clear C0024?
On a supported vehicle, CR Eagle P can organize available faults, freeze frame, live data and reports, and can clear erasable records after repair. Confirm exact ECU coverage. It cannot establish safe braking from an erase command or replace physical measurements for the GM brake-pedal simulator valve diagnosis.
The iCarsoft Official Store Technical Team maintains the store's fault-code library. This guide organizes published technical references and verified product information; it does not document a hands-on test of a particular vehicle or claim an individual engineer's review.
Technical and cost references
- GM bulletin 20-NA-073 — September 2020. Application-limited C0024 label and brake-control condition; check current VIN applicability and any superseding instructions.
- NHTSA DOT HS 812 574 — Hydraulic Braking System Appendices. March 2018; Appendix K, Table K-2 provides selected chassis-code labels. It does not replace current VIN-specific service information.
Product information: Official iCarsoft CR Eagle P page.
Editorial note: General diagnostic education, not a substitute for the owner's manual, current VIN-specific service information or professional inspection. Test limits, procedures, coverage and costs vary. Related articles provide context; apply only the specifications and repair procedures that match the vehicle. No universal failure rate, repair price or outcome is implied.
