MazicBay Diagnostics
MAZICBAYDiagnostics
FTC Reader Disclosure: When you purchase or register through links on our site, we may earn an affiliate commission at no extra cost to you. Read our Editorial & Advertising Policy.

P0457 on Cadillac Lyriq

EVAP System Leak Detected (Fuel Cap Loose/Off)

Factory diagnostic protocol and troubleshooting wire for fault code P0457 specifically for the Cadillac Lyriq (2023–2026, Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP)).

Verified OEM Telemetry & Field Repair Tree
Cadillac Lyriq2023–2026
Cadillac Lyriq
EVUltium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP)
Reliability
Sensor Voltage Ref
0.1V – 5.0V Ref
Lyriq SAE Mode $01
ECU Network Bus
500 kbps CAN-FD
ISO 15765-4 Compliant
Drivability Status
Drivable (Short Trip)
Low urgency level
Est. Repair Cost
$0 - $120 (DIY: $0 - $30)
Parts & Labor DIY
Check P0457 On Another Cadillac Model:
Diagnose P0457 on Specific Lyriq Model Year:

1. Symptoms of P0457 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 P0457, drivers commonly observe:

'CHECK FUEL CAP' message in dash display on Cadillac Lyriq (Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP))
Illuminated Check Engine Light on Cadillac Lyriq (Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP))
Slight gasoline vapor odor near fuel door on Cadillac Lyriq (Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP))
Cadillac Lyriq OBD-II Port Location
The 16-pin diagnostic connector is located Under driver steering column beneath knee bolster. Plug in your scan tool to verify freeze-frame sensor values.

2. Most Likely Causes on Cadillac Lyriq

Historical warranty claims and technical repair bulletins for Cadillac Lyriq point to the following failure distribution:

55%
Loose, unclicked, or forgotten gas cap (Cadillac OEM Part)
25%
Cracked, dried out, or missing rubber O-ring gasket on fuel cap (Cadillac OEM Part)
12%
Cracked filler neck neck where gas cap seals (Cadillac OEM Part)
8%
Faulty EVAP fuel tank pressure sensor (FTP) (Cadillac OEM Part)
* Source: Synthesized from NHTSA ODI field repair telemetry and verified OEM Technical Service Bulletin (TSB) repair tree frequency percentiles for Cadillac Lyriq.

3. Step-by-Step DIY Repair Guide for Cadillac Lyriq

01
Inspect and Tighten Gas Cap

Unscrew gas cap, inspect rubber seal for cracks, reinstall and turn until it clicks firmly 3 times. on the Cadillac Lyriq equipped with Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP).

Required Tool: None
02
Inspect Fuel Filler Neck Lip

Check the metal filler neck lip for rust, grit, or dings preventing a tight seal. on the Cadillac Lyriq equipped with Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP).

Required Tool: Clean Rag
03
Replace Gas Cap with OEM Replacement

If rubber gasket is flattened or hardened, buy a factory OEM gas cap. on the Cadillac Lyriq equipped with Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP).

Required Tool: OEM Gas Cap
04
Clear Trouble Code or Drive

Clear DTCs with scanner, or drive vehicle for 3–5 days until the PCM runs an overnight EVAP vacuum decay test and turns off the light automatically. on the Cadillac Lyriq equipped with Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP).

Required Tool: OBD-II Scanner
Recommended Parts & Testing Tools

Equipment for Diagnosing Cadillac Lyriq (P0457)

Prime Fast Delivery & Verified Fitment
EVAP Seal Replacement

OEM Tethered Fuel Gas Cap with O-Ring

4.7 / 5.0 (Direct Fit)

Tight-sealing factory fuel cap resolves common EVAP small/large leak codes without workshop visits.

$17 – $26 Prime
Check Fitment on Amazon
Sensor Signal Voltage Meter

AstroAI Auto-Ranging Digital Multimeter

4.6 / 5.0 (Best Seller)

Essential for testing 0.1V–5.0V sensor reference signals, ground continuity (<0.20Ω), and harness resistance.

$29.99 Prime
View on Amazon
Top Mobile OBD-II Scanner

BlueDriver Bluetooth Pro OBDII Scan Tool

4.7 / 5.0 (50,000+ Reviews)

Reads and clears enhanced codes (ABS, Airbag, Transmission, Engine) & live freeze-frame telemetry on phone.

Compare OEM & Aftermarket Replacement Sensors for Cadillac LyriqVerified direct-fit pricing from Denso, Bosch, Motorcraft, and ACDelco on Amazon.
Find Parts on Amazon
* As an Amazon Associate, MazicBay earns from qualifying purchases. Prices & availability subject to change.

Other Common Fault Codes on Cadillac Lyriq

Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Cadillac Lyriq:

4. Cadillac Lyriq P0457 FAQs

What causes code P0457 to trigger on a Cadillac Lyriq?

On the Cadillac Lyriq (Ultium Dual Motor AWD (500HP / 450 lb-ft) / Single Motor RWD (340HP)), P0457 is most frequently caused by Loose, unclicked, or forgotten gas cap or Cracked, dried out, or missing rubber O-ring gasket on fuel cap.

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 P0457?

Yes. Safe to drive indefinitely, but fuel vapors escape into the atmosphere. Given that P0457 carries a Low severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.