B3935 on 2015-2019 Chevrolet Silverado 3500: No-Start Causes and Fixes

What's Unique About the 2015-2019 Chevrolet SILVERADO 3500

The K2XX platform, which includes the 2015-2019 Silverado 3500 and its siblings (GMC Sierra, Tahoe, Suburban, Yukon, and Escalade), is known for the sensitivity of its immobilizer system. General Motors has issued multiple Technical Service Bulletins (TSBs) warning technicians that intermittent no-start conditions with code B3935 are frequently caused by external Radio Frequency Interference (RFI), not component failure. The official guidance in TSBs like #PIC5650L and its successors explicitly states not to replace parts until RFI has been ruled out. Additionally, some 2015 models may be affected by a BCM software glitch that requires a dealer-installed update, as noted in TSB #PI1180A, which is specific to a "No Click, No Crank, No Start" condition when B3935 is paired with B2955.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Intermittent no-crank, no-start condition. [Bulletin #PIC5650M]
• Engine starts and immediately stalls. [Bulletin #PIC5650M]
• Security indicator light is illuminated or flashing on the dashboard. 🎬 Watch: Troubleshooting a flashing security light and no-start condition. [Bulletin #PIC5650M, 5]
• A "No Click, No Crank, No Start" condition, especially when code B2955 is also present.
• Remote start may work, but the engine dies when the key is inserted and turned to 'ON'.

Most Likely Causes

1. Radio Frequency (RF) Interference 🔴 High Probability As documented in GM TSBs #PIC5650L and #PIC5650M, the immobilizer system on this platform is sensitive to external electronic signals. Common sources include other key fobs on the same ring, building access cards (RFID), toll passes, and aftermarket electronics like cheap, unshielded phone chargers or dash cams.
   How to confirm: Remove the Silverado key from your keychain. Ensure no other keys, fobs, or RFID cards are near the ignition or key. Unplug all aftermarket 12V accessories. Attempt to start the vehicle with the isolated key. If it starts, RF interference was the cause. This is the first diagnostic step recommended by GM.
   Typical fix: Identify and remove the source of RF interference. Keep other RFID-enabled cards and key fobs separate from the vehicle key. Replace low-quality aftermarket chargers with shielded, high-quality units.
   Est. part cost: $0
2. Body Control Module (BCM) Software Glitch 🟡 Medium Probability → Shop Body Control Module TSB #PI1180A specifically addresses 2015 Silverado 2500/3500 models. A software issue in the BCM can cause it to fail to read the immobilizer information correctly, causing a 'No Click, No Crank, No Start' and setting B3935 along with B2955.
   How to confirm: This issue must be diagnosed with a scan tool. If both B3935 and B2955 are present on a 2015 model, and the symptom is a "no click, no crank, no start," this is the likely cause. A dealer can verify if the update has already been applied.
   Typical fix: The Body Control Module needs to be reprogrammed with updated software by a GM dealer or a qualified shop with access to the Service Programming System (SPS). 🎬 See how a technician performs the BCM programming and setup. The warranty labor time for this procedure is 0.5 hours.
   Est. part cost: $0 (labor cost only)
3. Weak or Faulty Key ⚪ Low Probability While less common than RF interference, the internal transponder chip in the key can be damaged from being dropped, or the key fob battery can become weak, causing intermittent communication issues.
   How to confirm: Try starting the vehicle with your spare key. If the spare key works reliably, the primary key is likely faulty. You can also try replacing the battery in the key fob (typically a CR2032) as a low-cost test.
   Typical fix: Replace the faulty key. A new key will need to be cut and programmed to the vehicle by a dealer or an automotive locksmith.
   Est. part cost: $50-$250

Rare But Worth Checking

• Poor Body Control Module (BCM) Ground: → Shop Body Control Module

Diagnosis Steps

1. Verify the active symptoms: Security light on, no-crank/no-start, or start/stall. [Bulletin #PIC5650M]
2. Question the driver about any new electronic devices, keys, or access cards in the vehicle or on their person. [Bulletin #PIC5650L]
3. CRITICAL FIRST STEP: Remove the Silverado key from the keychain. Isolate it from all other keys, fobs, and RFID cards.
4. Unplug any aftermarket devices from the 12V power outlets (phone chargers, dash cams, etc.).
5. Attempt to start the vehicle with only the isolated Silverado key. If it starts, the issue is RF interference.
6. If the vehicle still does not start, try the spare key. If the spare key works, the primary key is likely faulty.
7. If neither key works and RF interference has been ruled out, connect a high-end scan tool.
8. Check for other codes. If B2955 is present with B3935 on a 2015 model, suspect the BCM software glitch (TSB #PI1180A).
9. If the BCM software update applies, have the module reprogrammed by a qualified technician.
10. If the issue persists, inspect the BCM ground connection (G218, behind the driver's side kick panel) for tightness and corrosion.
11. If all the above steps fail, further diagnosis of the BCM, wiring, and immobilizer antenna (ignition lock cylinder) may be required by a professional.

Parts You'll Likely Need

• None (RF Interference Mitigation) — The most common cause is RF interference, which requires removing the interfering object, not replacing a part. This is a $0 fix.
  OEM price range: $0
  Aftermarket price range: $0
• Key Fob Battery (OEM #CR2032) — A weak battery can sometimes cause communication issues. It's a cheap and easy item to replace as part of diagnosis.
  Trusted brands: Energizer, Duracell
  OEM price range: $5-$10
  Aftermarket price range: $2-$8
• Ignition Key / Fob (OEM #ACDelco 22881480 (Verify by VIN)) — If a spare key works and the primary does not (after ruling out RF interference and a weak battery), the key itself has likely failed and needs replacement and programming. Part number can vary by trim and options.
  Trusted brands: ACDelco
  OEM price range: $100-$250
  Aftermarket price range: $50-$150

Related Codes That Often Appear With This One

• B3055 — Often set with B3935, it relates to not receiving a signal from the key's transponder, frequently caused by the same RF interference. [Bulletin #PIC5650M, 3]
• B3060 — Indicates an unprogrammed transponder, which can be triggered during a failed authentication attempt alongside B3935. [Bulletin #PIC5650M, 3]
• B2955 — On 2015 models, this code is the key companion to B3935 that points directly to the BCM software issue described in TSB #PI1180A. If you have B3935 without B2955, the TSB does not apply.
• C0750 / C0755 / C0760 / C0765 / C0775 — These are Tire Pressure Monitor Sensor (TPMS) codes that can sometimes be set alongside B3935 due to broad RF interference or BCM communication issues, as noted in TSB #PIC5650M.

Technical Service Bulletins (TSBs) & Recalls

• PIC5650M: Addresses intermittent no crank/start/stall with security light on, lists B3935, and points to RF interference.
• PIC5650L: Explicitly warns technicians not to replace parts for this concern and to ask the customer about Radio Frequency Identification devices.
• PI1180A: Details a BCM software update for 2015 models that experience a no-start with codes B3935 and B2955.

Platform-Specific Known Issues

• A known sensitivity to Radio Frequency (RF) interference is the primary issue for this platform, as documented in TSBs #PIC5650L and #PIC5650M. The bulletins explicitly warn against replacing parts before investigating this as the root cause.
• For 2015 models specifically, a BCM software update may be required to fix a 'No Click, No Crank, No Start' condition where B3935 is set with B2955, per TSB #PI1180A.
• A poor ground connection at G218 (driver's kick panel) has been noted on K2XX platform vehicles as a potential source of various electrical issues, including this one.

Hidden / Shadow Codes Worth Checking

• B3935 57: Transponder Authentication Error: Invalid or Mismatched Key. This specific symptom byte indicates the BCM read the key's transponder value and recognized it as valid, but the cryptographic challenge/response calculation failed. This points away from a 'no signal' issue (like B3055) and toward a data corruption or interference problem. (see via A dealer-level scan tool like the GM GDS2 or a high-end professional scanner that can read manufacturer-specific symptom bytes.)

Scan Tool Commands That Help

• GDS2 (GM Global Diagnostic System 2): Module Diagnostics > Body Control Module > Immobilizer Learn — This function is required to program new keys or to resynchronize the system after replacing the BCM. It initiates a 10-12 minute security wait time to authorize new keys.
• GDS2 (GM Global Diagnostic System 2): Module Diagnostics > Body Control Module > Data Display > Immobilizer Data — Use this to view live data to see the 'state' of the security system. A technician can see the reason for the last security event, which is critical for confirming if the BCM is rejecting the key and why.
• SPS (Service Programming System): BCM Programming and Setup — This is the online system used with GDS2 to flash the BCM with new software. It is the required fix for the no-start condition on 2015 models when both B3935 and B2955 are present, as per TSB PI1180A.
• GDS2 (GM Global Diagnostic System 2): Serial Data Authentication Configuration (SDAC) — After replacing or reprogramming a module like the BCM, this security handshake must complete successfully. If it fails, it can cause a no-start and set codes like U1962. Running this procedure manually may be necessary if the immobilizer learn function fails.

Wiring & Ground Locations

• G218 — Inside the cabin, behind the driver's side dash panel, near the A-pillar speaker. Access requires removing the A-pillar trim and the side dash panel.. This is a primary ground point for the Body Control Module (BCM) and instrument cluster. A loose or corroded connection here, sometimes caused by insulation trapped under the nut from the factory, can cause intermittent BCM power loss, leading to failed key authentication and a B3935 code.
• BCM (Body Control Module) — Under the driver's side of the dashboard, to the left of the steering column and brake pedal. It is a black plastic box with multiple large electrical connectors.. The BCM is the central computer for the immobilizer system. It receives the key data, performs the authentication, and sends the start/disable command to the ECM. All relevant wiring terminates here.
• Immobilizer Fuse (F26) — In the fuse box located on the driver's side of the dashboard, accessible after opening the driver's door and removing the side dash cover. It is a 10A fuse.. This fuse supplies power to the immobilizer system. While a blown fuse is a rare cause for this specific code (which implies the system is powered but failing authentication), it's a valid check for any no-start condition involving the security system.

Real Owner Repair Stories

• Professional technician forum discussion (2014 Chevy Silverado (K2XX Platform)) — Persistent B3935 and B2955 codes with a no-crank condition.
  ❌ Tried (didn't work) Reprogramming the BCM per TSB PI1180A.
  ✅ What actually fixed it An improperly installed aftermarket remote start system had its T-harness tapping into the immobilizer data wire, causing signal corruption. The final fix was to remove the remote start harness and correctly splice the factory wires back together.
• YouTube User Comment (2014-2018 Chevy Silverado/GMC Sierra (K2XX Platform)) — Flickering dash lights, radio shutting down, intermittent no-start, and other random electrical issues.
  ❌ Tried (didn't work) Replacing battery, Checking fuses
  ✅ What actually fixed it The user located the G218 ground behind the driver's side dash, found it was loose or had insulation under it, cleaned the contact points to bare metal, and tightened the nut. This resolved all electrical issues.

OEM Part Supersession History

• 13587754, 13594963, 13598179 → 13506228 — Standard part revision and consolidation by the manufacturer.
  Heads up: When replacing a BCM, it is critical to match the part number or use a verified superseded number. A replacement BCM, new or used, is not plug-and-play and MUST be programmed to the vehicle's VIN using GM's Service Programming System (SPS) to function correctly.

Model Year Variations Within This Range

• 2015: Models from this year are specifically called out in TSB #PI1180A for a BCM software glitch that causes B3935 and B2955 to set together, resulting in a 'No Click, No Crank, No Start'. Later model years are not affected by this specific software issue.
• 2014-2016 vs 2017-2019: The layout of the interior fuse panel on the driver's side of the dash differs between these year groups, but the immobilizer fuse remains in position F26 for both layouts.