B1926 – Rear pretensioner squib (left) circuit open (Toyota)

Toyota-specific code — factory diagnostic data

B1926 means the Toyota RAV4 SRS system has a fault in the left rear seat belt pretensioner circuit, and the airbags may not protect you as designed. In real terms, you will usually see the SRS/airbag warning light and lose proper restraint control for that seating position. This is a Toyota manufacturer-specific code, and the exact test logic can vary by platform. According to Toyota factory diagnostic data, this code indicates an open circuit in the rear pretensioner squib (left) circuit. Treat this as a safety-critical electrical fault. Follow Toyota SRS depowering procedures before you touch any related connector.

🔍Decode any Toyota RAV4 VIN — free recalls, specs & safety ratings — free VIN decoder with NHTSA data

B1926 Quick Answer

On Toyota vehicles, B1926 points to an open circuit in the left rear pretensioner squib circuit. The SRS module cannot see the correct electrical load, so it disables that circuit and turns the airbag light on.

What Does B1926 Mean?

Official definition: Rear pretensioner squib (left) circuit open. The SRS airbag module logged B1926 because it cannot confirm continuity through the left rear pretensioner igniter circuit. In practice, the system flags a restraint fault and may limit deployment strategies to protect occupants.

What the module checks: The Toyota SRS ECU monitors the pretensioner squib circuit for a valid resistance range and stable continuity. An “open” means the ECU sees resistance too high or no current path. Why it matters: The DTC points to a suspected trouble area only. Per SAE J2012 guidance, the message does not name a failed part. You must prove whether the open comes from wiring, connectors, the pretensioner unit, or a terminal fit problem.

Theory of Operation

Under normal conditions, the Toyota SRS ECU supplies a low-energy monitoring signal to each squib circuit. The rear seat belt pretensioner contains an igniter (squib) that tightens the belt during a crash event. The ECU continuously checks that circuit so it can deploy reliably when needed.

B1926 sets when the ECU detects an open in the left rear pretensioner squib circuit. A disconnected connector, backed-out terminal, damaged harness, or high resistance at a contact can make the ECU read “open.” Because SRS circuits are tightly controlled, you must depower the SRS system and use OEM-approved methods. Do not probe squib circuits with standard test leads or a powered test light.

Symptoms

You will usually notice a warning first, then scan-tool confirmation with SRS access.

• SRS warning light stays on in the cluster
• Message display may show an airbag or safety system warning, depending on trim
• Disabled protection for the left rear pretensioner circuit during a fault condition
• Stored DTC B1926 present in the SRS airbag module memory
• Failed self-check SRS indicator does not complete its normal bulb check sequence
• Intermittent light if a loose connector opens only with seat movement or vibration
• Related codes may appear for other rear restraint circuits if a shared connector or harness section has issues

Common Causes

• Loose or partially seated rear seat pretensioner connector (left): A backed-out lock or poor terminal contact opens the squib circuit and the SRS airbag module flags an open.
• Corrosion or terminal fretting at the squib connector: Oxidation and micro-movement increase resistance until the module interprets the circuit as open.
• Harness damage under the rear seat or along the seat track path: Pinched, cut, or stretched wiring can break a conductor and create an intermittent or hard open.
• Connector damage from improper probing or aftermarket accessories: Standard test leads, back-probing, or added wiring near SRS looms can spread terminals and cause an open circuit.
• High resistance in the ground or return path for the pretensioner circuit: A weak splice, poor crimp, or stressed terminal can look like an “open” to the module during self-checks.
• Left rear pretensioner squib internal open: A failed squib element or internal connection opens the load, so the module cannot see expected circuit continuity.
• Misrouted or strained wiring after seat removal or interior work: Reassembly that traps the SRS harness under brackets or foam can break conductors over time.
• Wrong component installed or incorrect connector pairing: Mixing left/right or using a non-matching pretensioner sub-harness can prevent proper terminal engagement and trigger an open.

Diagnosis Steps

Use a scan tool with full Toyota SRS airbag access, plus OEM wiring diagrams and connector views for the RAV4. You also need a quality DMM and back-end voltage-drop leads. Follow Toyota SRS depowering procedures before touching any SRS connector. Do not probe squib circuits with standard test leads. Use only OEM-approved methods and adapters.

1. Connect the scan tool and confirm B1926 in the SRS airbag module. Record DTC status and any companion SRS codes. Save freeze frame data, focusing on battery voltage, ignition state, and when the code set. Freeze frame shows the conditions at the fault event. Use a scan-tool snapshot later to catch intermittent opens during a wiggle test.
2. Perform a fast visual check of the circuit path before meter work. Inspect the left rear seat area, under-seat harness routing, and any recent interior work zones. Look for pinched looms, pulled connectors, or signs of water intrusion. Stop if you find damaged yellow SRS wiring and plan a controlled repair.
3. Check SRS-related fuses and power distribution next. Verify fuse integrity and correct seating in the junction blocks. Do not assume a fuse is good by sight. A power feed issue can create multiple SRS codes, so document what else appears in the module.
4. Verify SRS airbag module power and ground under load with voltage-drop testing. Keep the circuit operating per Toyota service procedure. Measure ground drop while the module powers up. Accept less than 0.1 V drop on grounds under load. Do not rely on continuity alone.
5. Depower the SRS system using Toyota’s OEM procedure and wait the specified time. Confirm the system is disabled before disconnecting any SRS connectors. Never use an ohmmeter directly across a squib or pretensioner connector. Avoid static discharge and keep your body grounded.
6. Inspect the left rear pretensioner and harness connectors closely. Check CPA locks, secondary locks, terminal tension, and signs of spread terminals. Look for corrosion, moisture tracks, or damaged seals. Correct any connector seating issues first, since they often create intermittent opens.
7. Use OEM-approved test methods to isolate the open between the SRS airbag module and the left rear pretensioner connector. Follow Toyota service information for the correct adapter and check strategy. Verify each conductor for an open and for short-to-ground or short-to-power. Perform a controlled wiggle test on the harness while monitoring the circuit status with the scan tool.
8. If the harness checks good, test the pretensioner side per Toyota’s approved procedure. Many Toyota platforms require a specified load tool or service resistor in place of the squib for circuit testing. Confirm the module can recognize a proper load without setting B1926. This step differentiates a wiring open from a squib internal open.
9. After repairs, reconnect all components using correct routing and retainers. Repower the SRS system per OEM procedure. Clear codes with the SRS-capable scan tool. Cycle ignition and confirm the code does not return at key-on. Recheck for pending versus stored status, since a hard open typically resets immediately.
10. Run a final scan of the SRS airbag module and document the repair. Verify no related DTCs remain. If the concern was intermittent, capture a scan-tool snapshot during a controlled road test over bumps. Use that data to confirm the fix under real-world vibration.

Professional tip: On Toyota SRS circuits, the most common “open” culprit is connector contact, not the pretensioner itself. Focus on terminal fit, lock engagement, and harness strain near the rear seat first. Use voltage-drop principles for power and ground checks, and use only Toyota-approved load tools for squib circuit verification. That approach prevents accidental deployment risk and avoids unnecessary parts.

Possible Fixes

• Reseat and secure the left rear pretensioner connector: Restore proper terminal engagement, locks, and routing so the module sees a stable circuit.
• Repair harness damage using OEM-approved SRS wiring practices: Correct pinched or broken conductors and restore strain relief, clips, and protective covering.
• Clean or replace corroded terminals and connector bodies: Replace damaged terminals or connectors when corrosion or spread terminals prevent reliable contact.
• Correct harness routing and retention under the rear seat: Remove tension points and prevent future opens from seat movement or occupant loading.
• Replace the left rear pretensioner only after circuit verification: Confirm wiring integrity and module power/ground first, then replace the pretensioner if the squib itself tests open using OEM-approved methods.

Can I Still Drive With B1926?

You can usually drive a Toyota RAV4 with DTC B1926, but you should treat it as a safety-critical fault. B1926 means the SRS airbag module sees an open circuit on the rear pretensioner squib (left). That condition can disable that pretensioner, and it can also affect other SRS functions depending on Toyota’s internal fail-safe strategy. The vehicle will typically drive normally, but crash protection may drop. Do not attempt DIY probing at SRS connectors. Depower the SRS system using Toyota procedures before any inspection, and use a scan tool with full SRS access.

How Serious Is This Code?

This code ranges from “no drivability issue” to “major safety concern.” It rarely causes stalling or poor running. It often looks like an inconvenience because the only symptom may be an SRS warning light. However, the rear left pretensioner circuit can be compromised, and the SRS system may limit deployment logic when it detects a squib circuit open. Treat the SRS system as potentially compromised until you confirm the root cause and verify repair with an SRS-capable scan tool. Proper diagnosis requires SRS-safe test methods, correct depowering steps, and technician training. Avoid DIY repairs on squib circuits.

Common Misdiagnoses

Technicians often replace the rear left pretensioner first because the DTC “sounds like” a failed unit. That wastes money when the real fault sits in the connector, terminal fit, or harness routing. Another common mistake involves using a standard multimeter or test light directly on squib circuits. That can damage components or create a safety risk. Many shops also skip verifying SRS power and grounds and ignore freeze-frame or “current/history” status in the SRS airbag module. Finally, some try clearing codes repeatedly to “see if it comes back.” That does not prove a fix and can hide intermittent opens.

Most Likely Fix

The most common confirmed repair directions for B1926 involve correcting an open in the rear left pretensioner circuit rather than replacing the module. Start with the rear seat area pretensioner connector and harness routing. Look for poor terminal tension, backed-out pins, corrosion, or damage from seat movement. Next, verify continuity and integrity of the circuit between the pretensioner connector and the SRS airbag module using OEM-approved methods and the correct depowered procedure. Only after you prove the circuit wiring and terminals can you justify replacing the rear left pretensioner or related harness section.

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: April 8, 2026

Definition source: Toyota factory description · Autel MaxiSys Ultra & EV. Diagnostic guidance is based on factory-defined fault logic for this code.