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Federal filingsHome›Trouble codes› B3935
Diagnostic trouble code

B3935

1 owner report and 1,999 manufacturer filings across 406 model years from Buick, Cadillac, Chevrolet, GMC.

Body Manufacturer-specific 1,999 manufacturer filings 1 owner report

Where B3935 shows up

Source: NHTSA manufacturer communications and complaints
Model yearFiled underBulletinsOwner reportsParts
2016 GMC YukonElectrical System19—Battery →
2017 GMC YukonElectrical System18—Battery →
2016 Cadillac EscaladeElectrical System17—Battery →
2018 GMC YukonElectrical System17—Battery →
2018 Cadillac EscaladeElectrical System16—Battery →
2017 Cadillac EscaladeElectrical System14—Battery →
2016 Chevrolet ExpressNot specified13—
2017 Chevrolet ExpressElectrical System12—Battery →
2018 Cadillac CT6Electrical System11—Battery →
2017 Cadillac CT6Electrical System11—Battery →
2016 Cadillac CTSElectrical System11—Battery →
2018 Chevrolet ExpressElectrical System11—Battery →
2017 Chevrolet SparkElectrical System11—Battery →
2016 Chevrolet SparkElectrical System11—Battery →
2016 Chevrolet TahoeElectrical System11—Battery →
2017 GMC SavanaNot specified11—
2016 GMC SavanaNot specified11—
2018 GMC SierraElectrical System11—Battery →
2017 GMC SierraElectrical System11—Battery →
2016 GMC SierraElectrical System11—Battery →
2017 Buick CascadaElectrical System10—Battery →
2016 Buick CascadaElectrical System10—Battery →
2017 Buick EnclaveElectrical System10—Battery →
2016 Buick EnclaveElectrical System10—Battery →
2018 Buick EncoreElectrical System10—Battery →

Showing the 25 model years where B3935 appears most; it is on file for 406 in total.

A model year appears here because the code is named in its record, not because every one of these vehicles sets it. Counts are mentions in the federal files, not failure rates — nobody publishes the denominator.

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B3935 by make

The same record, one make at a time: the model years, bulletins and owner reports that name B3935 on that maker’s vehicles.

Chevrolet 190GMC 86Cadillac 79Buick 51

What it gets filed under

Electrical System 676 Not specified 353 Power Train 243 Engine 203 Air Bags 86 Equipment 76

What owners said

Source: NHTSA complaint database

Owners’ own words, one per nameplate, scrubbed of anything identifying. These are unverified reports filed with NHTSA — they are what was said, not a finding that it was true.

When putting shell premium gas I noticed my cars Rmps is way lower than usually and my acceleration is a lot slower/delayed I never had this problem when I put regular and midgrade (plus) gas furthermore I noticed I got a weird B3935 error…
2020 Chevrolet Trax Aug 1, 2025 NHTSA owner report

1,999 manufacturer filings name B3935. Start with what the maker wrote down.

A code names the test that failed, not the part. A bulletin that names it is often a diagnosis someone has already written down — quote its number at the service desk.

Photo: Compagnons / Unsplash

Manufacturer filings that name it

Source: NHTSA manufacturer communications

Service bulletins and campaigns whose filed summary names B3935.

What B3935 means

Source: SAE J2012 / OBD-II

B3935 is a manufacturer-specific code: the second character is a 3, which under the OBD-II standard hands the definition to whoever built the vehicle. The same code can mean one thing on a Ford and something unrelated on a Hyundai. Any site that prints a single definition for it is guessing.

A stored code names the test that failed, never the part that caused it. It is the starting point of a diagnosis, not its conclusion — the same code has several possible causes and the cheap one is not always right.

From here

Common questions about B3935

Source: NHTSA files and the OBD-II standard

Why does this page not define B3935?

Because it cannot be defined honestly. The second character of a trouble code says who owns its meaning, and a 1 or a 3 hands that to the manufacturer. Sites that print one definition for a manufacturer-specific code are showing you one automaker's meaning and hoping it is yours.

Can I keep driving with B3935 stored?

Nobody can answer that from the code alone, and a site that does is guessing. A steady light means a fault was logged and the car should be checked soon; a flashing light means a severe misfire — slow down and get it seen as soon as possible, because severe misfire can quickly damage the catalytic converter. The safe read of this page is the mileage and the components, not permission.

Does a code mean the car is recalled?

No. Recalls are filed by campaign and matched by VIN, and none of them are triggered by a scan tool. If you want to know whether an open recall applies to one specific vehicle, check the VIN at nhtsa.gov/recalls — that is the only source that settles it.

Why do the counts here differ from other sites?

Because these are not estimates. Every number on this page is a count of documents in NHTSA's own files: manufacturer communications that name the code in their filed summary, and owner complaints that name it in the narrative. We do not model, weight or extrapolate them.

Will clearing the code fix it?

Clearing turns the light off and erases the freeze-frame data a technician would have used to work out what happened. If the condition is still there the code returns, usually within a few drive cycles, and the diagnosis now starts from less information than before.