P0171 on Cadillac Lyriq: Fix & DLC Location
Factory diagnostic troubleshooting wire for fault code P0171 (P0171: System Too Lean (Bank 1)) specifically on the Cadillac Lyriq (2023–2026, Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP)).
1. Symptoms of P0171 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 P0171, 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 the battery, unclip the MAF sensor on the air intake tube, and spray 10-15 bursts of dedicated MAF cleaner onto the thin wire sensor. Allow to dry 15 minutes before reinstalling. on the Cadillac Lyriq equipped with Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP).
Check the rubber accordion hose between air filter box and throttle body for tears or dry rot cracks. on the Cadillac Lyriq equipped with Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP).
Shake the PCV valve; if it doesn't rattle cleanly, replace it. Inspect attached rubber hoses for collapsing. on the Cadillac Lyriq equipped with Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP).
Connect fuel pressure gauge to the Schrader valve on fuel rail. Verify pressure meets factory PSI specs. on the Cadillac Lyriq equipped with Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP).
Clear DTCs and verify Long Term Fuel Trims (LTFT) return below +/- 10% on your scanner. on the Cadillac Lyriq equipped with Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP).
Other Common Fault Codes on Cadillac Lyriq
Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Cadillac Lyriq:
4. Cadillac Lyriq P0171 FAQs
What causes code P0171 to trigger on a Cadillac Lyriq?
On the Cadillac Lyriq (Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP)), P0171 is most frequently caused by Dirty or failing Mass Air Flow (MAF) sensor or Cracked intake air boot or disconnected vacuum hose.
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 P0171?
Yes, but prolonged lean running increases cylinder combustion temperatures. Given that P0171 carries a Medium severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.