B3055 on 2015-2022 Chevrolet Equinox: No Start, Security Light Causes & Fixes

What's Unique About the 2015-2022 Chevrolet EQUINOX

The 2015-2022 Equinox range spans two generations with different key systems, which affects how B3055 presents. On the second-generation models (2015-2017) with a traditional flip-key, a GM Technical Service Bulletin (PIT5030E) points out that simply not having the key fully extended can cause this code and a no-start condition. For the third-generation models (2018-2022), which often feature a push-button start, the issue is more likely related to a weak key fob battery or interference, requiring the fob to be placed in a specific transmitter pocket in the front cupholder to start the vehicle.

Diagnostic Flowchart

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

Generation note: This range covers the end of the second generation (2015-2017) and the beginning of the third generation (2018-2022). The second generation typically uses a metal flip-key (e.g., Strattec P/N: 5912545, 5913597; GM P/N: 13504200) that is inserted into an ignition cylinder. The third generation primarily uses a keyless entry fob (e.g., Strattec P/N: 5942495; GM P/N: 13529665) with a push-button start. Causes and diagnostic steps can differ slightly between the two systems.

Symptoms You May Notice

• Engine does not crank or makes no attempt to start.
• Engine starts briefly and then immediately shuts off. [⭐ MANUFACTURER TSB — highest authority]
• The security indicator light (an icon of a car with a lock) is illuminated or flashing on the dashboard.
• A "Service Theft Deterrent System" message appears on the driver information center.
• For push-button start models, a "No Remote Detected" message may be displayed.

Most Likely Causes

1. Defective Ignition Key or Key Fob 🔴 High Probability → Shop Ignition Switch The internal transponder chip in the key can fail over time due to being dropped or from normal wear and tear. This is the most frequent point of failure in the system, sometimes intermittently.
   How to confirm: The easiest way to confirm is to try starting the vehicle with a spare key. If the spare key works reliably, the original key is faulty. A locksmith can also test the transponder chip directly.
   Typical fix: Replace the faulty key. A new key must be cut and programmed to the vehicle by a dealership or a qualified automotive locksmith.
   Est. part cost: $70-$200
2. Incorrect Flip-Key Position (2015-2017) 🟡 Medium Probability A GM Technical Service Bulletin (PIT5030E) notes that if the flip-key is not fully extended and locked in the straight position, its transponder may not align correctly with the reader coil in the ignition, causing an intermittent no-start.
   How to confirm: If the vehicle fails to start, remove the key, ensure it is fully clicked open and straight, and re-insert it. If the vehicle then starts, this was the cause.
   Typical fix: No parts needed. This is a user-awareness issue. 🎬 Watch: How to easily replace your flip key remote battery. Always ensure the key is fully extended before inserting it into the ignition.
   Est. part cost: $0
3. Weak or Dead Key Fob Battery (2018-2022) 🟡 Medium Probability → Shop Vehicle Battery On push-button start models, the key fob's battery is required for the car to detect its presence. A weak battery can prevent this communication.
   How to confirm: A "No Remote Detected" message is a strong indicator. Try placing the key fob in the designated transmitter pocket (located in the front section of the center console cupholder 🎬 Watch: How to find the transmitter pocket and start your car.) and attempt to start the vehicle. If it starts, the fob battery is weak.
   Typical fix: Replace the CR2032 battery inside the key fob.
   Est. part cost: $5-$10
4. Signal Interference ⚪ Low Probability Other transponder keys, key fobs, or strong RFID-blocking wallets on the same keychain can interfere with the signal from the correct key. GM TSB PIC5650 also warns that aftermarket electronics like USB chargers and LED interior lights can cause Radio Frequency Interference (RFI) that jams the key's signal.
   How to confirm: Remove all other keys and electronic devices from the keychain so only the single Equinox key is present. Unplug any aftermarket chargers or devices from the vehicle's power outlets. Attempt to start the vehicle.
   Typical fix: Keep the vehicle key separate from other fobs or large numbers of keys. Remove low-quality aftermarket electronics.
   Est. part cost: $0
5. Faulty Immobilizer Exciter Coil (Antenna) ⚪ Low Probability The exciter coil is a wire antenna that surrounds the ignition lock cylinder. It energizes the transponder chip in the key. If this coil or its wiring fails, it cannot read any key, new or old.
   How to confirm: If multiple known-good keys fail to start the vehicle, the exciter coil is a likely suspect. A technician can test the circuit for continuity and proper resistance (typically looking for less than 10 ohms on the ground circuit and checking for shorts).
   Typical fix: Replace the immobilizer exciter coil/antenna module, which is often part of the ignition lock cylinder assembly. The wiring pigtail (e.g., GM P/N 13587321) may also need replacement if corroded or damaged.
   Est. part cost: $50-$150

Rare But Worth Checking

• Faulty Body Control Module (BCM): → Shop Body Control Module While uncommon, the BCM is the brain of the anti-theft system. If it fails internally, it may not be able to read a valid key or send the correct password to the ECM. This is typically diagnosed after all other possibilities (key, antenna, wiring) have been ruled out. A low vehicle battery can also cause communication issues with the BCM, sometimes triggering this code.

Diagnosis Steps

1. Check the dashboard for a flashing or solid security light. This confirms an anti-theft issue.
2. If you have a spare key, try to start the vehicle with it. If it works, the first key is bad.
3. For 2015-2017 models with a flip key, remove the key, ensure it is fully extended and locked straight, then re-insert and try again.
4. For 2018-2022 models with push-button start, try replacing the CR2032 battery in the key fob. If it still doesn't work, place the fob flat in the transmitter pocket (in the front cupholder) and try starting.
5. Remove all other keys, fobs, and electronic devices from the keychain to eliminate signal interference. Unplug any aftermarket phone chargers or accessories.
6. Attempt the '30-Minute Key Relearn Procedure': Turn the key to the 'ON' position (without starting) and leave it for approximately 10 minutes until the security light stops flashing and turns off. Turn the key off for 5-10 seconds. Repeat this process two more times for a total of three 10-minute cycles. After the third cycle, turn the key off and then try to start the engine.
7. If the vehicle still won't start, professional diagnosis is required. A technician will use a scan tool to check communication with the Theft Deterrent Module/BCM and test the exciter coil circuit for opens, shorts, or high resistance.

Parts You'll Likely Need

• Transponder Ignition Key (Flip Key, 2015-2017) (OEM #13504200) — This is the most common point of failure for the keyed ignition system. The internal chip can be damaged, preventing the car from recognizing it.
  Trusted brands: ACDelco, Strattec (P/N: 5912545 or 5913597)
  OEM price range: $100-$200
  Aftermarket price range: $40-$90
• Smart Key Fob (Push-Button Start, 2018-2022) (OEM #13529665) — For push-button start models, the entire fob can fail, though a dead battery is more common. A replacement requires professional programming.
  Trusted brands: ACDelco, Strattec (P/N: 5942495)
  OEM price range: $120-$220
  Aftermarket price range: $50-$100
• Key Fob Battery (CR2032) — For push-button start models, a dead battery is a frequent cause of the 'No Remote Detected' message, which is related to this fault.
  Trusted brands: Duracell, Energizer
  OEM price range: $5-$10
  Aftermarket price range: $2-$5

Related Codes That Often Appear With This One

• B3060 — This code relates to an Unprogrammed Transponder. It often appears with B3055 if a new, unprogrammed key is used or if the system loses its memory. [⭐ MANUFACTURER TSB — highest authority]
• B3935 — Transponder Authentication Failed. This indicates the system read a key, but the key's security code did not match what was stored in the vehicle's memory. [⭐ MANUFACTURER TSB — highest authority]

Technical Service Bulletins (TSBs) & Recalls

• PIT5030E: Diagnostic Tip - Intermittent No Crank When Ignition Key Is Turned To The Crank Position.
• PIC5650M: Intermittent no crank, no start, or start stall concern with the security light coming on. [⭐ MANUFACTURER TSB — highest authority]

Platform-Specific Known Issues

• A known issue on 2010-2014+ GM models, including the Equinox, is an intermittent no-crank caused by the flip key not being fully extended, which sets a history code for B3055. This is documented in TSB PIT5030E.

Mechanic-Grade Diagnostic Values

• Theft Deterrent Module Ground Circuit Resistance — expected: Less than 10 ohms. Failure: A value greater than 10 ohms indicates an open or high resistance in the ground circuit.
• Theft Deterrent Module Signal Circuit Voltage (Key ON) — expected: Less than 1.0 V. Failure: A value greater than 1.0 V indicates a short to voltage on the signal circuit.
• Theft Deterrent Module Signal Circuit Resistance to Ground — expected: Infinite resistance (OL). Failure: Any reading less than infinite resistance indicates a short to ground on the signal circuit.

Scan Tool Commands That Help

• GDS2 (GM Global Diagnostic System 2): Immobilizer Learn — Used after replacing the BCM or when all keys need to be relearned to the vehicle. This is a comprehensive security programming function.
• GDS2 (GM Global Diagnostic System 2): Add/Replace Key Fobs — Used when adding a new key or replacing a single lost/damaged key. This function is found under the 'Remote Control Door Lock Receiver' module diagnostics.
• GDS2 (GM Global Diagnostic System 2): Module Diagnostics > BCM > Data Display — Used to view live data parameters like 'Transponder Key' status (Present/Not Present) to determine if the BCM is recognizing an attempt to read a key.

Wiring & Ground Locations

• Body Control Module (BCM) — For 2015-2017 models, the BCM is located under the driver's side of the dashboard.. The BCM is the primary module for the theft deterrent system on these models. All immobilizer wiring connects here.
• Body Control Module (BCM) — For 2018-2022 models, the BCM is located on the passenger side of the center console, accessible by removing the side trim panel.. The BCM's location changed with the generation redesign. Knowing the correct location is critical for diagnosis and checking connections.
• BCM Connector C4, Pin 26 — On the BCM of 2010-2017 models, this is a BLACK with WHITE stripe wire.. This is a primary ground connection for the BCM. A poor connection here can cause various electrical issues, including immobilizer faults.
• Engine Block Ground (G104) — On some 2018+ models, a key ground point (G104) is located on the left side of the engine block. Another critical PCM ground is located under the alternator on the 2.4L engine.. While not directly for the immobilizer coil, poor engine and module grounds can cause communication errors between the BCM and ECM, leading to no-start conditions and various codes.

Real Owner Repair Stories

• YouTube channel 'ADD AUTOMOBILE SERVICES' (2013 Chevrolet Equinox) — Intermittent no-start with security light on and DTC B3055. The key would sometimes work and sometimes not.
  ❌ Tried (didn't work) Cycling the key multiple times.
  ✅ What actually fixed it The technician used a VVDI key tool to read the intermittent original transponder chip and clone its data onto a new, stable 'super chip'. He then placed this new chip inside the original key housing, effectively creating a redundant signal. The car started reliably afterward.
• YouTube channel 'Hands On Auto Training' (2015 Chevrolet Malibu (similar GM platform)) — No crank, no start with a current DTC B3055 'No Transponder Modulation'.
  ❌ Tried (didn't work) Clearing the codes (the B3055 code returned immediately).
  ✅ What actually fixed it The original key's transponder had failed. The technician used a professional scan/programming tool (AutoProPAD) to perform the 'Immobilizer Learn' function and program a brand new key to the vehicle. The car started immediately with the new key.

When the Usual Fixes Don't Work

• While Pass 2 correctly identifies common causes like faulty keys and antennas, a significant number of intermittent cases that are difficult to diagnose are caused by Radio Frequency Interference (RFI), as detailed in multiple GM Technical Service Bulletins (PIC5650 series). Technicians may replace keys or modules unnecessarily if they don't first investigate and remove all aftermarket electronic devices (phone chargers, LED lights, dash cams) from the vehicle to see if the problem resolves. The issue is often that the customer removes the interfering device before the service appointment, making the fault impossible to replicate.

OEM Part Supersession History

• 13587321 (GM) → PT2930 (ACDelco) — Brand part number cross-reference.
  Heads up: This is the same part, a multi-purpose pigtail connector often used for the immobilizer exciter coil wiring. It is not a supersession but an alternative part number from GM's own brand, ACDelco.

Model Year Variations Within This Range

• 2015-2022: All vehicles in this year range require the GM GDS2 (Global Diagnostic System 2) software for immobilizer diagnostics and key programming. The older Tech2/Tech2Win tools are not compatible.
• 2015-2017 vs 2018-2022: The Body Control Module (BCM) is in a different location. On 2015-2017 models, it is under the driver's side dashboard. On 2018-2022 models, it is behind the passenger side trim panel of the center console.