B0137 – Left pretensioner squib circuit short to ground

B0137 means the airbag system detected an electrical short to ground in the left belt pretensioner circuit. In plain terms, the SRS warning light usually turns on and the system may disable part of the restraint protection. This is a safety-critical fault, so do not touch SRS connectors until you follow the OEM depowering procedure. According to manufacturer factory diagnostic data, this code indicates a “Left pretensioner squib circuit short to ground.” The code points to a suspected circuit problem, not a confirmed bad pretensioner. You must prove the short with approved SRS test methods before replacing parts.

B0137 Quick Answer

B0137 points to a short-to-ground condition in the left pretensioner squib circuit. Start with SRS depower, then inspect the left pretensioner wiring and connectors for chafing or pinched insulation before condemning any component.

What Does B0137 Mean?

B0137 code means the SRS/airbag control module flagged the left pretensioner squib circuit as “short to ground.” In practice, that usually turns on the airbag light and can inhibit pretensioner or related deployment logic. The module does not prove the pretensioner failed. It only reports it sees an abnormal electrical condition in that circuit.

Technically, the SRS module monitors the squib loop for expected resistance and isolation. A short to ground occurs when either squib wire contacts chassis ground or a grounded shield. The module can also interpret internal shorting bar issues at connectors as a shorted condition. That distinction matters because the correct repair may be a harness or connector fault, not a pretensioner or SRS module replacement.

Theory of Operation

The left pretensioner contains a pyrotechnic squib that tightens the belt during a crash event. The SRS module controls that squib through a dedicated two-wire loop. Under normal conditions, the module sees a stable, isolated circuit with no path to vehicle ground.

B0137 sets when the module detects the loop pulled toward ground. Harness damage under the commonly causes that. movement can pinch wiring and rub insulation through. A compromised connector, shorting bar, or water intrusion can also create a ground path that the module interprets as a short.

Symptoms

Because B0137 involves the SRS pretensioner circuit, symptoms center on airbag system warnings and disabled protection.

• Warning light: Airbag/SRS indicator stays on, sometimes with a “Service Airbag” message.
• Scan tool: B0137 stored as current or history, often with additional pretensioner or -related SRS codes.
• Safety function: The left pretensioner may be disabled, and the module may alter deployment strategy.
• Intermittent behavior: Light may change with position or after moving the fore/aft.
• After repair work: Code appears after removal, upholstery work, or console work near the pretensioner harness.
• Inspection clue: Visible harness scuffing or a crushed loom under the driver-side area on left-hand-drive vehicles.

Common Causes

• Chafed pretensioner harness contacting body ground: Insulation damage lets the squib circuit touch metal, so the SRS module sees a short to ground.
• Corrosion or moisture in the left pretensioner connector: Water intrusion bridges terminals to ground paths and pulls the circuit low.
• Connector damage from movement: A stretched or partially unseated connector can deform terminals and create an unintended ground contact.
• Pinched wiring under the track: track hardware can crush the harness and force the conductor into contact with grounded structures.
• Aftermarket , upholstery, or remote-start wiring interference: Non-OEM work often reroutes or ties into harnesses and creates shorts near SRS wiring.
• Shorted pretensioner squib (component internal fault): An internal short in the pretensioner’s initiator circuit can mimic a harness short to ground.
• Terminal back-out or mis-pin at the SRS module connector: A backed-out terminal can contact adjacent grounded shielding or the connector shell.
• High-resistance ground strategy masking as a short (rare): A compromised module ground can distort the module’s circuit diagnostics and falsely flag a short-to-ground condition.

Diagnosis Steps

Use a scan tool with full SRS access, OEM wiring diagrams, and the manufacturer’s SRS depower procedure. Keep an approved DVOM available, but do not probe squib circuits with standard test leads. Use OEM-approved breakout tools and shorting bars when specified. Plan for voltage-drop testing on SRS power and grounds under load.

1. Confirm B0137 with an SRS-capable scan tool and record code status. Capture freeze frame or event data, including battery voltage, ignition state, vehicle speed, and any other SRS DTCs. A hard short-to-ground often resets immediately at key-on after you restore power.
2. Follow the OEM SRS depowering procedure before touching any pretensioner or SRS connectors. Disable the system, wait the specified time, and verify the system remains depowered. Do not use a test light anywhere on SRS circuits.
3. Check SRS fuses and power distribution feeds first. Inspect related fuse block cavities for heat damage and loose terminals. Do not jump to the SRS module connector until you confirm clean power delivery upstream.
4. Verify SRS module power and grounds with voltage-drop testing under load. Backprobe only where the OEM allows, or use an approved breakout harness. Target less than 0.1 V drop on grounds with the circuit operating, because continuity alone misses high resistance.
5. Perform a focused visual inspection of the left pretensioner circuit path before any resistance checks. Inspect under- routing, track pinch points, sharp brackets, and any signs of previous removal. Look for rubbed-through loom, exposed copper, or tape repairs.
6. Disconnect and inspect the left pretensioner connector and the related harness connector(s) using OEM handling rules. Check for corrosion, bent pins, terminal spread, or a partially latched connector. Verify the connector CPA/lock engages and the harness has proper strain relief.
7. Isolate the harness from the pretensioner and test the squib circuit for short-to-ground using OEM-approved methods. Measure the harness side only, at the points the OEM specifies, and never apply power to a squib. If the short disappears when you disconnect a segment, you just narrowed the fault location.
8. Wiggle-test the harness while monitoring the scan tool’s SRS data and DTC status, with the system powered only when the OEM allows it. If the short appears with movement or harness flex, focus on that physical area. Use a scan tool snapshot to capture the moment the fault returns during your manipulation.
9. If the harness checks good, follow the OEM test that substitutes an approved simulator or test load in place of the pretensioner. This step helps separate a harness short from a possible internal pretensioner issue. Never substitute resistors unless the service information explicitly approves it.
10. After repairs, reassemble all connectors, confirm proper routing, and restore SRS power per OEM procedure. Clear codes only after you correct the fault and complete all required SRS checks. Re-scan to confirm B0137 does not reset and no additional SRS codes appear.

Professional tip: Treat B0137 as a wiring fault until you prove otherwise. Most confirmed fixes come from finding a pinched harness under the track or moisture in a connector. Also, do not trust an ohmmeter reading alone; a marginal short can disappear when the harness relaxes, so use isolation and controlled wiggle tests to make the fault repeat safely.

Possible Fixes

• Repair damaged wiring and restore proper harness routing and retention under the to prevent re-chafing.
• Clean, dry, and correct connector issues, including terminal repair or replacement when the OEM permits it.
• Remove aftermarket wiring or hardware interference and return the SRS harness to factory routing and clips.
• Replace the left pretensioner only after you confirm the harness does not short to ground and the OEM test points to the component.
• Repair SRS power or ground faults found by voltage-drop testing, including loose grounds or overheated fuse connections.
• Repair connector pin fit or terminal back-out at the SRS module connector using OEM-approved terminal service parts and procedures.

Can I Still Drive With B0137?

You can usually drive the vehicle with a B0137 code, but you should treat it as an SRS safety problem, not a convenience issue. B0137 means the SRS module sees the left pretensioner squib circuit shorted to ground. That condition can disable the affected pretensioner and may disable other SRS functions, depending on the vehicle design. The car will still steer, stop, and run normally in most cases, but crash protection may not work as designed. Do not attempt DIY probing at the pretensioner or SRS connectors. Do not unplug connectors with the battery connected. Follow the OEM SRS depowering procedure and have an SRS-capable scan tool confirm which loop the module flagged.

How Serious Is This Code?

B0137 is serious because it involves a squib circuit, which is part of the deployment system. In day-to-day driving, you may only notice the airbag light and a stored DTC. In a collision, the consequence can be major because the left pretensioner may not fire, or the system may inhibit deployment to prevent an unintended event. A short-to-ground fault also raises handling risk during service because incorrect test methods can trigger additional faults or damage the SRS module’s firing circuit. Diagnosis requires OEM-approved SRS procedures, proper depowering, and a scan tool with full SRS access. If you lack SRS training and equipment, do not attempt this repair at home.

Common Misdiagnoses

The most common mistake is replacing the left pretensioner or belt assembly before proving the circuit short. Techs often find B0137 and assume the squib failed. . Another frequent error involves using a standard ohmmeter or test light on a squib circuit. That can violate OEM procedures and create new SRS faults. Shops also miss poor terminal tension because the connector “looks fine.” Confirm the short-to-ground with OEM-approved breakout methods and circuit checks from the SRS module side.

Most Likely Fix

The most common confirmed repair path for B0137 starts with correcting a short-to-ground in the left pretensioner squib wiring between the SRS module and the pretensioner connector. That often means repairing chafed insulation, rerouting or securing the under- harness, or replacing a damaged connector or terminals. If circuit integrity checks good and the short disappears when you isolate the pretensioner (using OEM-approved methods), the pretensioner unit becomes a stronger suspect. After repairs, clear the SRS DTC with an SRS-capable scan tool and perform the OEM verification procedure. Many vehicles require an ignition cycle sequence and a self-test to confirm the fix.

Repair Costs

SRS/airbag repair costs vary significantly by component. Diagnosis must be performed by a qualified technician with SRS-capable equipment. Do not attempt airbag system repairs without proper training and safety procedures.

Last updated: March 30, 2026