B0013 on 2008-2015 Cadillac CTS: Airbag Light Causes and Fixes

What's Unique About the 2008-2015 Cadillac CTS

For this specific vehicle range, General Motors has issued two key Technical Service Bulletins (TSBs) that pinpoint common, inexpensive connection-related failures as the root cause, rather than a bad airbag itself. For the second generation (2008-2014), a faulty Connector Position Assurance (CPA) retainer is a known issue. For the early third generation (2015), the focus shifts to poor terminal tension in a specific clock spring connector. This platform-specific history means the fix is often simpler and cheaper than replacing major components.

Diagnostic Flowchart

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

Generation note: This range covers two CTS generations, and the most likely cause can differ: - Second Generation (2008-2014): More likely to be affected by the issue described in TSB #08-09-41-002H, which points to a broken or loose Connector Position Assurance (CPA) retainer on an airbag system connector. - Third Generation (2015 model year): More likely to be affected by the issue in TSB #PI1474, which identifies poor terminal tension in the steering wheel air bag coil connector, specifically on vehicles built between August 1 and October 1, 2014.

Symptoms You May Notice

• Air Bag warning light is illuminated on the instrument panel.
• "Service Airbag" message may appear on the Driver Information Center (DIC).

Most Likely Causes

1. Broken or Loose Connector Position Assurance (CPA) Retainer 🔴 High Probability This is a well-documented issue across dozens of GM vehicles from this era, as cited in TSB #08-09-41-002H. 🎬 See how these GM airbag codes relate to connector issues. The small plastic retainers become brittle over time and can break or fall out, causing a loose connection at an SIR module or harness connector.
   How to confirm: After safely disabling the SIR system, visually inspect the yellow airbag connectors at the back of the airbag module and at the clock spring. The CPA is a small, often black, plastic clip that locks the main connector in place. If it's missing, broken, or doesn't 'click' into place, this is the likely cause.
   Typical fix: Replace the broken CPA retainer. The connector itself is usually fine. The part is often GM P/N 88988974.
   Est. part cost: $5-$15
2. Poor Terminal Tension in Clock Spring Connector 🔴 High Probability Specifically called out for the 2015 CTS (and 2015 ATS) in TSB #PI1474. The female terminals within the X85 steering wheel air bag coil X3 connector can lose their grip on the male pins, leading to an intermittent or open circuit. This TSB applies to vehicles built between August 1 and October 1, 2014.
   How to confirm: This requires using a special terminal test probe (like J-35616) to check the tension of each pin in the connector. If the probe feels loose, the tension is poor. This should be done before replacing the clock spring or airbag module.
   Typical fix: Replace the faulty connector with a new service connector pigtail (GM Part #13580115, also known as ACDelco PT2630). This involves cutting the old connector off and splicing the new one in, then re-wrapping the harness.
   Est. part cost: $20-$50
3. Faulty Clock Spring (Steering Wheel Air Bag Coil) 🟡 Medium Probability The clock spring contains a flexible ribbon cable that winds and unwinds as the steering wheel turns. Over time, this cable can fatigue and break, causing an open circuit. This is a common wear item on many vehicles.
   How to confirm: If both the CPA and terminal tension are good, the clock spring is the next suspect. This is confirmed by testing for continuity through the clock spring for the Stage 2 circuit. If the circuit is open, the clock spring is bad. A 2009 CTS-V owner on YouTube confirmed a broken clock spring caused his 'Service Airbag' light after other steering work was performed. 🎬 Watch: A 2009 CTS-V owner demonstrates this clock spring failure.
   Typical fix: Replace the clock spring assembly. This requires removing the steering wheel.
   Est. part cost: $70-$200

Rare But Worth Checking

• Faulty Driver's Airbag Module: While possible, this should only be considered after all wiring, connectors, and the clock spring have been ruled out. The issue is more often in the connection to the airbag than the airbag itself. Both TSBs for this issue explicitly state to check connections before replacing the airbag module.
• Damaged Wiring Harness: A wire could be chafed or broken somewhere between the clock spring and the main Sensing and Diagnostic Module (SDM). This is uncommon without other signs of damage or recent repair work in the steering column or dash.
• Faulty Sensing and Diagnostic Module (SDM): This is the least likely cause. The SDM is the computer for the airbag system, and failure is rare. It should be the last item to be considered for replacement after all other components and wiring have been verified as good. Note that GM has had recalls on other models for SDM software issues, but they are not the primary cause for this specific code on this platform.

Diagnosis Steps

1. SAFETY WARNING: The following steps must begin by properly disabling the SIR/airbag system. Typically, this involves disconnecting the negative battery terminal and waiting at least 2 minutes (some sources recommend up to an hour to be safe) for the system's backup power to discharge. Failure to do so can result in accidental deployment and serious injury.
2. Read the specific DTC with a scan tool capable of reading SRS/Body codes to confirm B0013 is present and note the symptom bytes (e.g., 04, 0D, 0E).
🎬 Watch: Step-by-step guide to fixing airbag code B0013.
3. Disable the SIR system.
4. Remove the driver's airbag module from the steering wheel. This usually involves inserting a tool into small holes on the side or back of the steering wheel to release spring clips.
5. For 2008-2014 models (or if TSB PI1474 doesn't apply): Inspect the yellow airbag connector and its CPA retainer on the back of the airbag module. Check if the CPA (P/N 88988974) is broken, loose, or missing. Also inspect the connector at the base of the clock spring.
6. For 2015 models (built Aug-Oct 2014): Pay close attention to the X85 steering wheel air bag coil X3 connector. If a visual inspection reveals no issues, test the terminal tension in the connector using the appropriate tool (e.g., J-35616), as described in TSB #PI1474.
7. If poor terminal tension is found, replace the connector with the pigtail service part (GM P/N 13580115).
8. If all connectors and terminals are confirmed to be good, test the clock spring for continuity on the Stage 2 circuit. If the circuit is open or has high resistance, the clock spring is faulty.
9. If the clock spring tests good, inspect the wiring harness between the clock spring and the SDM for damage.
10. If all wiring and components test normal, the fault may lie within the airbag module itself or, rarely, the SDM.

Parts You'll Likely Need

• Connector Position Assurance (CPA) Retainer (OEM #88988974) — This small plastic clip is the common failure point noted in TSB #08-09-41-002H and is the most likely and cheapest fix, especially on 2008-2014 models.
  Trusted brands: ACDelco, GM Genuine Parts
  OEM price range: $3-$10
  Aftermarket price range: $2-$8
• Steering Wheel Air Bag Coil Connector (OEM #13580115) — TSB #PI1474 identifies this as the fix for poor terminal tension, a common issue on 2015 models built in a specific date range. It is sold as a pigtail for splicing.
  Trusted brands: ACDelco (P/N: PT2630), GM Genuine Parts
  OEM price range: $20-$40
  Aftermarket price range: $15-$30
• Clock Spring (Steering Wheel Module Coil) — If the connectors are not the issue, the internal ribbon cable of the clock spring is the next most likely component to have failed due to wear from steering rotation.
  Trusted brands: ACDelco, Standard Motor Products, Dorman
  OEM price range: $70-$200

Related Codes That Often Appear With This One

• B0012 — B0012 refers to the 'Driver Steering Wheel Air Bag Deployment Loop Stage 1'. Since both Stage 1 and Stage 2 circuits run through the same connectors and clock spring, a loose connector (due to a bad CPA) or failing clock spring can often trigger both codes simultaneously. Both TSBs PI1474 and 08-09-41-002H explicitly mention B0012 alongside B0013.

Technical Service Bulletins (TSBs) & Recalls

• PI1474: Air Bag indicator Illuminated with DTC B0012 or B0013.
• 08-09-41-002H: Intermittent AIR BAG Indicator/Lamp Illuminated with DTC(s) B0012, B0013... Set (Inspect and Replace Connector Position Assurance (CPA) Retainer).

Platform-Specific Known Issues

• TSB #08-09-41-002H documents that an intermittent airbag light with code B0013 (and many others) can be caused by a loose, missing, or damaged Connector Position Assurance (CPA) retainer on an SIR connector. This applies to the 2008-2014 CTS.
• TSB #PI1474 for 2015 models states that code B0013 can be caused by poor terminal tension in the steering wheel air bag coil connector, requiring connector replacement with P/N 13580115. This is specific to vehicles built between August 1 and October 1, 2014.

Mechanic-Grade Diagnostic Values

• Driver Steering Wheel Air Bag Deployment Loop 2 Resistance — expected: Normal resistance is typically between 1.74 and 3.41 ohms.. Failure: A resistance greater than 5.1 ohms will set a B0013 0D. A resistance below a certain threshold (e.g., <~1.7 ohms) will set a B0013 0E.

Hidden / Shadow Codes Worth Checking

• B0013 01: Driver Steering Wheel Air Bag Deployment Loop Stage 2 Short to Battery. (see via Requires a professional scan tool capable of reading GM-specific SRS codes and symptom bytes, such as a Tech2 or GDS2.)
• B0013 02: Driver Steering Wheel Air Bag Deployment Loop Stage 2 Short to Ground. (see via Requires a professional scan tool capable of reading GM-specific SRS codes and symptom bytes, such as a Tech2 or GDS2.)
• B0013 04: Driver Steering Wheel Air Bag Deployment Loop Stage 2 Open Circuit. This is a common symptom byte for the issues described in the TSBs. (see via Requires a professional scan tool capable of reading GM-specific SRS codes and symptom bytes, such as a Tech2 or GDS2.)
• B0013 0D: Driver Steering Wheel Air Bag Deployment Loop Stage 2 Resistance Above Threshold. This is a common symptom byte for the issues described in the TSBs. (see via Requires a professional scan tool capable of reading GM-specific SRS codes and symptom bytes, such as a Tech2 or GDS2.)
• B0013 0E: Driver Steering Wheel Air Bag Deployment Loop Stage 2 Resistance Below Threshold. (see via Requires a professional scan tool capable of reading GM-specific SRS codes and symptom bytes, such as a Tech2 or GDS2.)

Scan Tool Commands That Help

• GDS2 (GM Global Diagnostic System 2): Data Display > Deployment Loop Resistance Data — Use this to monitor the live resistance value of the deployment loop while diagnosing an intermittent connection. For example, wiggling wires or turning the steering wheel while watching this data can help pinpoint the location of the fault. One GM document specifies the path: Module Diagnostics > K36 Restraints Control Module > Data Display > Deployment Loop 1-14 Resistance Data.
• Professional SRS Scan Tool: Clear DTCs / Erase Codes — After a repair is completed, the airbag light will not turn off by itself. A scan tool capable of communicating with the SRS module is required to clear the stored B0013 code. A basic engine code reader will not work.

Wiring & Ground Locations

• Sensing and Diagnostic Module (SDM) — In the Cadillac CTS, the SDM is typically located under the center console, between the two front seats, bolted to the floor pan.. This is the central computer for the entire airbag system. All deployment loop circuits, including the one for B0013, terminate here. While SDM failure is rare, inspecting its connectors for corrosion or damage is a valid step in advanced diagnosis after all other components have been checked.
• X85 Steering Wheel Air Bag Coil X3 connector — This connector is part of the clock spring (air bag coil) assembly located within the steering column, behind the steering wheel.. This is a primary failure point for the 2015 model year, as identified in TSB #PI1474. Poor terminal tension within this specific connector can cause an open or high resistance circuit, triggering code B0013.

Real Owner Repair Stories

• YouTube channel 'well hello friends' (2006 Chevrolet Malibu (demonstrates the same TSB #08-09-41-002E that applies to the CTS)) — Airbag light on with code B0013.
  ✅ What actually fixed it The Connector Position Assurance (CPA) clip on the back of the driver's airbag was found to be broken. Replacing the small plastic CPA clip (GM P/N 88988974) and clearing the codes with a scan tool resolved the issue completely.

OEM Part Supersession History

• 88987853 → 13580115 — Standard part update/replacement.
  Heads up: The new part number, 13580115, is the correct service pigtail connector to use for the repair outlined in TSB #PI1474. It is also sold under the ACDelco part number PT2630.