B0091 on Cadillac Lyriq
Factory diagnostic protocol and troubleshooting wire for fault code B0091 specifically for the Cadillac Lyriq (2023–2026, Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP)).
1. Symptoms of B0091 on Cadillac Lyriq
When the Engine Control Module (ECM/PCM) on your Cadillac Lyriq (Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP)) logs fault code B0091, drivers commonly observe:
2. Most Likely Causes on Cadillac Lyriq
Historical warranty claims and technical repair bulletins for Cadillac Lyriq point to the following failure distribution:
3. Step-by-Step DIY Repair Guide for Cadillac Lyriq
Disconnect battery negative cable and wait 15 minutes to fully discharge SRS backup capacitors before touching airbag components. on the Cadillac Lyriq equipped with Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP).
Remove driver side door sill trim / lower B-pillar trim to access the yellow impact sensor. on the Cadillac Lyriq equipped with Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP).
Inspect sensor for water corrosion or cracked plastic housing. on the Cadillac Lyriq equipped with Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP).
Bolt new OEM side impact sensor into clean, rust-free ground location, torque bolt to spec, and click yellow locking connector firmly. on the Cadillac Lyriq equipped with Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP).
Reconnect battery, clear SRS trouble codes with an airbag-capable scanner, and verify light turns off after 5-second bulb check. on the Cadillac Lyriq equipped with Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP).
Equipment for Diagnosing Cadillac Lyriq (B0091)
Cadillac Lyriq OEM Replacement Sensor
Direct-fit replacement assembly engineered to OEM tolerances for Cadillac Lyriq.
AstroAI Auto-Ranging Digital Multimeter
Essential for testing 0.1V–5.0V sensor reference signals, ground continuity (<0.20Ω), and harness resistance.
BlueDriver Bluetooth Pro OBDII Scan Tool
Reads and clears enhanced codes (ABS, Airbag, Transmission, Engine) & live freeze-frame telemetry on phone.
Other Common Fault Codes on Cadillac Lyriq
Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Cadillac Lyriq:
4. Cadillac Lyriq B0091 FAQs
What causes code B0091 to trigger on a Cadillac Lyriq?
On the Cadillac Lyriq (Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP)), B0091 is most frequently caused by Corroded or damaged left side impact crash sensor (B-pillar or door sill) or Corroded wiring harness under driver seat / driver door sill.
Where is the OBD-II port located on my Cadillac Lyriq?
On the Cadillac Lyriq, the 16-pin DLC diagnostic connector is located Under driver steering column beneath knee bolster. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.
Can I safely drive my Cadillac Lyriq with code B0091?
Caution. Side curtain and seat airbag deployment may be disabled in a side-impact collision. Given that B0091 carries a Critical severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.