B3978

Incorrect Environmental Identifier Received from Inflatable Restraint Sensing and Diagnostic Module

Severity

🔴 High

Can you drive?

Do not drive — repair immediately

Approx. repair cost

$167–444 (est.)

Symptoms

Airbag light is on
The safety system may not work in an accident
The error does not disappear after a scanner reset

Causes

Security module firmware mismatch
Damage to the wiring harness between modules
Incorrect replacement of security components
Corrosion or poor contact in connectors
SDM module failure

How to Fix

Diagnostics of the communication bus using an oscilloscope
Checking software versions of all security modules
Updating or flashing modules
Checking the integrity of the wiring harness
Replacement of faulty components if necessary

Related codes

B0028 B0051 U0121