B1A20

Code

Generic B — Body

Manufacturer-Specific: Passenger Airbag Circuit Fault

Brand: Generic

Type: B — Body

Views: UK: 10 EN: 15 RU: 8

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Open or short in passenger airbag squib (inflator) wiring
Corroded, loose or damaged airbag connector at the passenger airbag
Poor connection at the SRS/airbag control module connector
Faulty passenger airbag squib (inflator)
Faulty SRS/airbag control module or internal driver circuit
Damage to wiring harness (pinched, chafed, water ingress)

Symptoms

SRS/airbag warning lamp illuminated or flashing
Possible disabling of passenger airbag (passenger airbag OFF light active)
Diagnostic trouble code stored in SRS module (B1A20)
Inconsistent passenger airbag enable/disable behavior
Potential loss of passenger-side airbag deployment readiness

What to check

Read and record all SRS codes and freeze-frame data with a capable scan tool
Verify battery voltage and good power/ground to SRS control module
Visually inspect passenger airbag connector(s) and harness for damage, corrosion, or moisture
Check for other related codes (occupant classification, seatbelt pretensioner, module faults)
Measure continuity and resistance of the passenger airbag squib with an ohmmeter (see signal_params)
Perform wiggle test on wiring while monitoring live data and resistance for intermittent faults

Signal parameters

Passenger airbag squib resistance: typically low (commonly ~2–5 ohms for most squibs). Exact spec is manufacturer-specific — consult service data
Open-circuit: infinite/OL on ohmmeter between squib pins
Short to ground: near 0 ohms between squib circuit and chassis ground
Short to battery: near 0 ohms between squib circuit and battery positive (with respect to supply rail)
Module supply voltage: battery voltage present at SRS power pins (typically ~12 V) when key on

Diagnostic algorithm

Safety first: follow manufacturer procedures to disable SRS power before accessing airbag connectors (disconnect battery and wait the specified time or use diagnostic service procedure).
Connect a compatible scan tool, confirm B1A20 and record any additional SRS codes and freeze-frame data.
Visually inspect passenger airbag area and wiring harness for physical damage, signs of impact, water ingress or corrosion.
Locate passenger airbag connector(s). With SRS power disabled per service instructions, disconnect and inspect pins for corrosion, bent pins, or loose terminals.
Measure squib resistance at the airbag connector with an ohmmeter. Compare to manufacturer specification (typical low-ohm value). An open or very high resistance indicates a broken/open circuit; very low near zero suggests a short.
If resistance is out of range, isolate the harness and check continuity between the airbag connector and the SRS module connector. Repair any opens or shorts found.
If wiring and connectors check good, swap or bench-test the passenger airbag (only if service procedures allow) or replace with a known-good module following safety rules.
If wiring and squib test normal, inspect and test the SRS/airbag control module connectors and grounds. Replace or reprogram module only when confirmed faulty and per manufacturer instructions.
Clear codes and perform verification: reconnect power, clear codes with scan tool, and re-check for reappearance of B1A20 during system self-checks and by performing any manufacturer-specified verification steps.
If intermittent fault persists, perform wiggle/stress tests on harness while monitoring live resistance and DTCs to locate hidden breaks.

Likely causes

Disconnected or corroded connector at passenger airbag
Short to ground or short to battery in the passenger airbag wiring
High resistance in squib (partial break or corrosion)
Faulty passenger airbag module (squib)
Intermittent wiring fault in dash harness

Fault status

⚠️ Status

Passenger airbag circuit fault detected — open/short/high resistance in passenger airbag loop or related wiring/connectors. SRS module has stored B1A20.

🔴 Repair difficulty: Hard

⏱️ Diagnostic time: 0.5-2.5 hours