OBD Guide

P05B8

Restraint Deployment Signal Circuit/Open

Severity
🔴 High
Can you drive?
Do not drive — repair immediately

Symptoms

  • The SRS (airbag) or Check Engine light is on
  • Possible incomplete activation of emergency algorithms during an accident
  • Other security systems may not receive a trigger signal
  • SRS self-diagnosis detects intersystem communication error

Causes

  • Open signal circuit wire between SRS module and ECU
  • Damaged or disconnected connector in the circuit
  • Oxidation of connector contacts
  • Damage to SRS module with loss of output signal
  • Open circuit in the wiring harness (under the dashboard or under the seats)

How to Fix

  1. ATTENTION: before working with the SRS system, disconnect the battery and wait at least 10 minutes for the capacitors to discharge
  2. Read codes from the SRS module with a specialized scanner
  3. Check the wiring and signal circuit connectors between the SRS module and the ECU
  4. Measure the circuit resistance (with the connectors disconnected)
  5. Check the integrity of the wiring harness under the instrument panel
  6. Repair the break or replace the SRS module if it is faulty
  7. It is recommended to entrust diagnostics and repair of SRS to a specialist

Related codes

Error P05B8 by Vehicle Brand