B0078 high Severity

B0078: Third Row Right Seatbelt Pretensioner Deployment Control (Subfault)

No direct engine or driveline impact but indicates fault in safety restraint system which could compromise occupant protection.

Overview

B0078 indicates a fault with the third row right seatbelt pretensioner control circuit in the Supplemental Restraint System (SRS) potentially due to wiring, sensor, or module issues.

Common Symptoms

  • Airbag / SRS warning light illuminated on dashboard
  • Stored code B0078 in SRS module
  • Potential non‑deployment of third row right seatbelt pretensioner in crash scenarios

Most Common Causes

Faulty seatbelt pretensioner (third row right) medium

Component internal failure can trigger code; requires testing.

Wiring harness damage or poor connection to pretensioner high

Corrosion, breaks, or loose connectors common in third row area.

Fault within SRS control module medium

Occasionally module internal errors or communication problems.

Diagnostic Steps

  1. Use advanced scan tool capable of reading SRS/B‑codes to confirm B0078 and related SRS codes.
    Expected: B0078 present and no contradictory codes.
    Interpretation: Confirms right third row pretensioner circuit fault.
  2. Perform visual inspection of wiring and connectors under third row right seat and associated pretensioner harness.
    Expected: Check for broken wires, corrosion, loose or unseated connectors.
    Interpretation: Faulty wiring/connectors likely if damage found.
  3. Measure continuity and resistance in pretensioner circuit with multimeter per factory specs.
    Expected: Circuit continuity within spec and resistance within expected range.
    Interpretation: Open, short, or out‑of‑spec resistance indicates wiring or pretensioner issue.
  4. Test/replace third row right seatbelt pretensioner if wiring checks pass but component is suspect.
    Expected: Pretensioner component operation confirmed or replaced.
    Interpretation: If code clears after pretensioner replacement, original was faulty.
  5. Check SRS control module for faults and perform module reset or reprogramming if needed.
    Expected: No internal module faults and proper communication with sensors.
    Interpretation: Module issues suspected if faults persist after wiring/component repair.

Repair Solutions

Repair or replace damaged wiring/connectors in pretensioner circuit medium
Estimated Cost: $50 - $300

Labour varies by vehicle; harness repair may be required.

Replace third row right seatbelt pretensioner hard
Estimated Cost: $200 - $600

Safety component replacement often expensive; OEM part recommended.

SRS control module reprogramming or replacement hard
Estimated Cost: $300 - $1200

Only if diagnostics confirm module fault; needs dealer‑level tool.

Common Misdiagnoses

Avoid these common diagnostic mistakes:

  • Confusing B0078 with generic passenger impact sensor codes; this specific code refers to seatbelt pretensioner deployment control.

Frequently Asked Questions

Technical definition of B0078 OBD-II Code

The B0078 code stands for Third Row Right Seatbelt Pretensioner Deployment Control (Subfault). This generally indicates an issue with the Sensors system.

How serious is the B0078 code?

With a severity level of high, no direct engine or driveline impact but indicates fault in safety restraint system which could compromise occupant protection.

What happens when the B0078 code is active?

Drivers often report: Airbag / SRS warning light illuminated on dashboard, Stored code B0078 in SRS module, Potential non‑deployment of third row right seatbelt pretensioner in crash scenarios when this code is present.

Potential causes for OBDII code B0078

Potential culprits include: Faulty seatbelt pretensioner (third row right), Wiring harness damage or poor connection to pretensioner, Fault within SRS control module. A proper diagnosis is recommended.

What is the price difference for fixing B0078?

Expect to pay around $300 if the issue is a Repair or replace damaged wiring/connectors in pretensioner circuit, but up to $1200 if the SRS control module reprogramming or replacement needs replacement.

Does B0078 affect Ford, Toyota, or Honda?

The B0078 code is a generic powertrain code, meaning it applies to almost all makes and models, such as Honda, Toyota, VW, Ford, and Chevy.

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