B1937 — Air Bag Passenger Pressure Switch Circuit Open

body electrical

Is it safe to drive?

Drive with caution The car drives normally, but with the SRS light on the airbags may not deploy in a crash. Treat it as a safety-critical repair: fine to drive to the shop, not fine to ignore for months.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm B1937 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many B0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the airbag / restraint system (SRS) for damage, corrosion, chafing or poor contact.
Subsystem check Do a continuity test end-to-end on the air bag passenger pressure switch circuit and wiggle the harness while measuring — intermittent opens show up as fluctuating readings.
Subsystem check Read the SRS module with a scanner that supports airbag systems — generic OBD2 readers cannot see these codes.
Subsystem check Inspect under-seat connectors — they are often disturbed by seat movement or cleaning.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm B1937 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for B1937 (parts and labor, USD, independent shop rates): SRS module reset or replacement: $300–$1,000; Reconnect or repair SRS wiring/connectors: $80–$250; Replace a sensor or clockspring: $150–$500. Overall, fixing B1937 usually costs between $80 and $1,000. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

Is it safe to drive with B1937?

The car drives normally, but with the SRS light on the airbags may not deploy in a crash. Treat it as a safety-critical repair: fine to drive to the shop, not fine to ignore for months.

How do I diagnose B1937 myself?

Start with a scan: confirm B1937, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the air bag passenger pressure switch, and verify the suspect component against live data before buying parts.

What does OBD2 code B1937 mean?

Air Bag Passenger Pressure Switch Circuit Open (B1937): a body electrical fault affecting the airbag / restraint system (SRS). Short, gentle driving to a shop is usually possible. Most often caused by failed clockspring (driver airbag circuit), SRS control module fault or stored crash data, faulty impact or occupancy sensor.

What are the symptoms of B1937?

Drivers most often notice: airbag system disabled message, no other driving symptoms, airbag (SRS) warning light on.

How much does it cost to fix B1937?

SRS module reset or replacement — $300–$1,000; Reconnect or repair SRS wiring/connectors — $80–$250; Replace a sensor or clockspring — $150–$500. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

When your vehicle's computer detects that the electrical pathway feeding the passenger airbag pressure switch has been interrupted, it logs trouble code B1937. This fault lives in the body control module or supplemental restraint system (SRS) computer, depending on your vehicle's architecture. The code specifically flags an open circuit condition — meaning the module sent voltage down the line and received no signal back, or the circuit resistance measured infinity instead of the expected value.

The passenger pressure switch tells the SRS module whether the front seat is occupied and, if so, how much force the passenger airbag should deliver in a collision. It's a simple pressure-sensitive device mounted in the seat cushion. When someone sits down, the switch closes and the module knows to arm the passenger airbag. If that switch loses its electrical connection entirely, the module can't confirm seat status and defaults to treating the seat as empty or invalid. Repeated failures across multiple drive cycles trigger B1937 and illuminate the airbag warning light on your dash.

What makes this code tricky is that it describes the symptom — an open circuit — rather than naming the exact failed part. The break could be in the switch itself, in the wiring between the switch and module, in a connector that backed out, or even in the module's own output stage. Freeze frame data stored alongside B1937 captures engine RPM, vehicle speed, and temperature at the moment of detection, giving you reproducible test conditions to chase the intermittent.

Symptoms of B1937

Illuminated airbag (SRS) warning light stays on after engine start
Dashboard displays "airbag system disabled" or similar restraint system message
No noticeable engine performance issues or drivability complaints
Possible intermittent warning light behavior if the open is temperature-dependent
Passenger airbag may not deploy regardless of seat occupancy
In rare cases, multiple SRS codes appear alongside B1937

Common Causes of B1937

The most frequent culprit is a loose or corroded connector, particularly under the front seats where wiring endures constant flexing. Seat removal for cleaning or cargo hauling often disturbs these connections just enough to create an intermittent open.

Disconnected or backed-out wiring connector at the pressure switch or module
Corrosion on connector pins from spills, moisture, or age
Broken or chafed wires in the seat harness from repeated flex cycles
Internally failed passenger pressure switch (less common but possible with age)
Blown fuse protecting the SRS circuit
Failed clockspring (affects the driver side circuit but related wiring runs nearby)
Low system voltage or depleted backup battery causing intermittent module behavior
Stored crash data or module failure in the SRS computer itself

How to Diagnose B1937

Before buying any parts, confirm you have the right code and rule out easy fixes.

Scan for B1937 with a capable OBD2 scanner — use a tool that reads manufacturer-specific SRS codes, not just generic powertrain codes. Save the freeze frame data and note any related codes in the restraint system.
Research factory technical service bulletins for your make, model, and year. Search the NHTSA database or your manufacturer's site using your VIN. Some vehicles have known software updates or harness modifications that resolve B1937 without parts replacement.
Perform a visual inspection of the passenger seat area. Pull back the seat trim, check the harness routing along the seat rails, and look for pinched, chafed, or melted wire insulation. Inspect connectors for bent pins, moisture intrusion, or corrosion deposits.
Test circuit continuity end-to-end from the pressure switch to the SRS module. Use a digital multimeter in resistance mode. With the harness disconnected at both ends, a reading above 1 ohm indicates a problem. Wiggle the harness during testing to catch intermittent opens.
If the wiring checks out, test the pressure switch itself for internal continuity when the seat is unloaded versus loaded. Compare your readings against manufacturer specifications.
Verify system voltage and check the relevant fuses. A weak backup battery in the SRS module can cause false opens that clear after a battery charge or replacement.
After repairs, clear B1937, complete a full drive cycle that matches the freeze frame conditions, and verify the light stays off.

Repair Options for B1937

Costs vary widely depending on which component actually failed. Work from cheap to expensive.

Reconnect or repair wiring/connectors: $80–$250
Replace passenger pressure switch sensor: $150–$500
Replace clockspring: $150–$500
SRS module reset or replacement: $300–$1,000

Total Cost to Fix B1937

At independent shop labor rates, the total bill typically lands between $80 and $1,000 depending on what needs fixing. Most cases involve connector issues or loose wiring, which cost the least to resolve. Module replacement is the worst-case scenario and should only be pursued after wiring and sensor tests confirm those components are good. An accurate diagnosis upfront prevents spending $1,000 on a new module when the problem was a loose seat connector.

Can You Drive with B1937?

B1937 itself causes no engine running problems. Your car drives, steers, and brakes exactly as designed. The safety risk is that the passenger airbag may not deploy in a collision if the module can't confirm seat status. Treat this as a caution-level issue: safe to drive to a repair facility, but not something to ignore indefinitely. Get it diagnosed within a week or two rather than months down the road.