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DTC codes / B00xx · Airbags, seats, doors, lights and comfort systems / B0073

B0073Driver Seatbelt Pretensioner Loop Short to Ground

B0073 means the restraint control module has detected a short to ground on the driver seatbelt pretensioner circuit, which is the pyrotechnic device that tightens the belt during a crash. The module monitors the loop resistance and sees it pulled to chassis ground instead of the expected value, so it disables that pretensioner and turns on the airbag warning light.

SystemBody
Code typeGeneric (all makes)
SeverityHigh
Fix difficultyProfessional
AreaAirbags, seats, doors, lights and comfort systems

Symptoms you may notice

  • Airbag or supplemental restraint system warning light illuminated on the dashboard
  • Often no symptoms besides the warning light, with the belt and buckle feeling completely normal
  • The driver seatbelt pretensioner will not deploy in a collision while the fault is stored
  • In some vehicles the restraint module logs a history code and may also disable other functions on the same circuit
  • Intermittent warning light that comes and goes when the seat is moved or the belt is buckled

Common causes, most likely first

  1. Damaged or chafed pretensioner wiring harness shorting against the seat frame or floor pan
  2. Corroded or loose connector pins at the pretensioner pigtail or the under-seat inline connector
  3. Moisture or water intrusion into the connector or the pretensioner housing causing a ground path
  4. Internal short to ground inside the pretensioner squib itself
  5. Pinched harness where the seat track slides over the wiring during seat adjustment
  6. Faulty restraint control module with an internal short on the driver pretensioner driver circuit

How to diagnose and fix it

  1. Disconnect the battery and wait the manufacturer-specified time, then inspect the driver seatbelt pretensioner connector and harness for chafing, corrosion, or pinched wires
  2. Measure resistance from the pretensioner side of the connector to chassis ground with the module disconnected; a near-zero reading confirms a short in the harness or squib
  3. Isolate the fault by disconnecting the pretensioner and rechecking the code; if the short clears, the squib is suspect, and if it remains, the harness or module is suspect
  4. Perform a wiggle test on the under-seat harness while watching live resistance data or the code status to catch intermittent shorts
  5. Repair or replace the damaged section of harness and any corroded terminals, then clear the code and verify the loop resistance is within specification
  6. If the harness and squib test good, substitute a known-good restraint control module only after confirming power and ground integrity at the module
  7. After repair, clear all codes and perform the manufacturer's restraint system verification, confirming no codes return after a road test over rough surfaces

What a shorted pretensioner loop really means

  • A short to ground on the pretensioner loop is often caused by the seat track slicing the harness as the driver adjusts the seat, so always inspect the wiring under full seat travel rather than at one position.
  • The code does not always mean the pretensioner is bad; a corroded connector pin or a chafed wire grounding on the seat frame produces the same stored fault and is far cheaper to fix.
  • Never probe or measure resistance directly across the pretensioner squib with a powered meter, because the small test current can trigger deployment; always use the manufacturer's specified tool and procedure.
  • A weak or failing restraint control module ground can create a false short-to-ground reading, so verify the module's own ground circuit before condemning the pretensioner or harness.
  • After any repair, the restraint module may need a learn or clear procedure with a capable scan tool, and some vehicles will keep the airbag light on until the stored crash or fault data is cleared properly.

Can I keep driving with B0073?

The vehicle is safe to drive normally because the pretensioner is disabled, not deployed, but the driver seatbelt will not tighten in a crash, so avoid aggressive driving and get the fault repaired promptly. Do not attempt to repair the pretensioner circuit yourself unless you are trained in restraint systems, because accidental deployment can cause serious injury.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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