B0001

B0001 means Driver Frontal Stage 1 Deployment Control has a fault — the airbag control module (RCM/ACM/SDM depending on manufacturer) has tested the driver-side frontal airbag squib circuit and either measured a resistance out of spec, detected an open or shorted squib, or seen its own deployment driver fail self-test. This is a hard SRS code: the airbag warning lamp is on solid, the driver airbag is almost certainly disabled, and the vehicle should not be driven for an extended period in that state. Diagnostic order, cheapest first AND safest first — and this is the single most important rule in SRS diagnostics: NEVER probe live SRS circuits with a multimeter, NEVER apply 12V or any voltage source to a squib, and NEVER use a non-SRS-rated test light anywhere in the SRS harness, because the squib (igniter) fires at as little as 1.2 amps of test current and accidental deployment is a $1,500+ replacement and a real injury hazard from the inflator gas. Step 1: With the battery disconnected for at least 3 minutes (capacitor discharge time inside the RCM), unbolt the driver-side clock-spring connector at the steering column and inspect the connector for corrosion, bent pins, or contamination — the clock-spring is the rotating contact between the steering-wheel airbag and the body harness, and a corroded clock-spring pigtail is the #1 cause of B0001 on vehicles past 8 years old. (2) With battery still disconnected, use an SRS-rated load box (Snap-on, Launch, Otofix, or OEM tools — these substitute a calibrated 2.0-ohm resistor for the squib and let you read the rest of the circuit without firing anything) to measure the loop resistance from the RCM connector through the clock-spring to the airbag connector; typical squib resistance is 1.5-3 ohms and the harness should add less than 0.5 ohms on top. (3) If the loop resistance reads OK with the load box but the code returns when the real squib is reconnected, the airbag itself is the fault — replace the inflator module. (4) If the loop reads open or wildly out of spec, the clock-spring is the part; replacing a clock-spring on most vehicles is a 1-2 hr job with a mandatory SRS scan-tool 'rearm' afterward. Hand a B0001 to a tech without SRS training and you can damage a $400 airbag, deploy a $1,500 inflator, or injure yourself.

Vehicle-specific patterns: 2005-2010 Chevy Cobalt / Pontiac G5 / HHR are the highest-volume B0001 ticket in North America because the GM ignition-switch recall (which produced 124 confirmed deaths and millions of vehicle recalls) is intertwined with clock-spring failure on these same platforms — if a Cobalt comes in with B0001 plus any ignition-position weirdness, check the recall completion before quoting any work, the clock-spring and ignition switch are both potentially recall-covered. 2002-2016 Honda Accord / Civic / CR-V / Odyssey / Pilot / Acura models with Takata airbag inflators are subject to the largest automotive recall in U.S. history (over 67 million inflators), and B0001 on any of these vehicles should be VIN-checked against the NHTSA recall database before any repair quote — the inflator and sometimes the entire module are covered. 2007-2014 Ford F-150 / Expedition / Lincoln Navigator with the cruise-control / horn / airbag combined clock-spring throws B0001 from clock-spring tape wear after 80k miles of steering input. 2004-2010 Toyota Tacoma / 4Runner throws B0001 from harness chafe inside the steering column where the clock-spring pigtail flexes. Estimated repair: $0 (recall coverage on Takata or GM ignition cluster) to $900 (clock-spring replacement plus SRS rearm and inflator if needed at a dealer).