Excessive Dump/Isolation Time (GM)
The C0274 code means the vehicle's onboard diagnostic system has detected: Excessive Dump/Isolation Time (GM). This is a serious severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $100 - $600 (wheel-speed sensor or wiring most often; EBCM/pump work costs more)
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Basic scanners cannot read ABS codes. This one reads all four systems so you know exactly which sensor failed.
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What Are the Symptoms of C0274?
- ABS and/or traction control warning lights on
- ABS and stability assist may be disabled (base brakes still work)
- Possible false ABS activation at low speed with a failing wheel-speed sensor
What Causes C0274? (Most Likely First)
- Fault in the ABS/traction control component this code names (Excessive Dump/Isolation Time) High
- Damaged wiring or a corroded connector in that circuit - road-splash zones corrode connectors High
- Failed related sensor or actuator Moderate
- Control module fault Low
Can I Still Drive with C0274?
Yes, but fix soon. C0274 is rated serious severity. It is not an immediate stop-driving fault, but it will not clear itself — book the repair rather than ignoring the light.
Frequently Asked Questions
What does C0274 mean?
C0274 is a chassis code used primarily by GM vehicles: Excessive Dump/Isolation Time. It concerns the ABS/traction control system.
Can I keep driving with C0274?
Base brakes keep working, but assume ABS and stability control are offline until repaired - allow longer stopping distances and drive gently, especially in rain or snow. Repair promptly.
Is C0274 the same on every make?
The decimal C0xxx range is dominated by GM's assignments (Chevrolet, GMC, Buick, Cadillac). Other makes may use this ID differently - if your vehicle is not a GM product, verify the meaning in your make's service information.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose C0274?
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Read the code with a GM-capable scan tool and note the symptom byte/subcode if shown.
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View live data for the named circuit (e.g. all four wheel speeds while rolling for wheel-speed codes).
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Inspect the circuit's wiring and connectors - chassis harnesses live in the splash zone and corrode first.
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Follow the GM pinpoint test for C0274 before replacing components.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
Which Vehicles Commonly Get C0274?
- Chevrolet, GMC, Buick, Cadillac (GM chassis code range)
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