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P0135 on Cadillac CT5-V Blackwing: Fix & DLC Location

Factory diagnostic troubleshooting wire for fault code P0135 (O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)) specifically on the Cadillac CT5-V Blackwing (2022–2026, 6.2L Handbuilt Supercharged LT4 V8 (668HP / 659 lb-ft / 6-Speed Manual / 10-Speed Auto)).

Cadillac CT5-V Blackwing
DIY Parts Estimate
$80 - $240 (DIY Sensor: $45)
CT5-V Blackwing OEM Fitment
Shop Labor Quote
$180 – $380
Based on $165/hr labor
Drivability Status
Drivable (Short Trip)
Low to Medium urgency level
Est. DIY Time
45 – 90 Min
Basic hand tools
Check P0135 On Another Cadillac Model:
Cadillac EscaladeCadillac Escalade-VCadillac CT5Cadillac CT5-V BlackwingCadillac XT5Cadillac Lyriq

1. Symptoms of P0135 on Cadillac CT5-V Blackwing

When the Engine Control Module (ECM/PCM) on your Cadillac CT5-V Blackwing (6.2L Handbuilt Supercharged LT4 V8 (668HP / 659 lb-ft / 6-Speed Manual / 10-Speed Auto)) logs fault code P0135, drivers commonly observe:

Check Engine Light on on Cadillac CT5-V Blackwing (6.2L Handbuilt Supercharged LT4 V8 (668HP / 659 lb-ft / 6-Speed Manual / 10-Speed Auto))
Slightly increased fuel consumption on short trips on Cadillac CT5-V Blackwing (6.2L Handbuilt Supercharged LT4 V8 (668HP / 659 lb-ft / 6-Speed Manual / 10-Speed Auto))
Failed state emissions inspection on Cadillac CT5-V Blackwing (6.2L Handbuilt Supercharged LT4 V8 (668HP / 659 lb-ft / 6-Speed Manual / 10-Speed Auto))
Cadillac CT5-V Blackwing OBD-II Port Location
The 16-pin diagnostic connector is located Driver A-pillar base kick panel. Plug in your scan tool to verify freeze-frame sensor values.

2. Most Likely Causes on Cadillac CT5-V Blackwing

Historical warranty claims and technical repair bulletins for Cadillac CT5-V Blackwing point to the following failure distribution:

55%
Burnt-out internal heating element in upstream oxygen sensor (Cadillac OEM Part)
25%
Blown O2 sensor heater fuse (Cadillac OEM Part)
12%
Melted or damaged sensor wiring near exhaust manifold (Cadillac OEM Part)
8%
Excessive circuit resistance (Cadillac OEM Part)

3. Step-by-Step DIY Repair Guide for Cadillac CT5-V Blackwing

01
Check the Heater Fuse

Locate the under-hood fuse box and test the O2 sensor heater fuse with a multimeter or test light. on the Cadillac CT5-V Blackwing equipped with 6.2L Handbuilt Supercharged LT4 V8 (668HP / 659 lb-ft / 6-Speed Manual / 10-Speed Auto).

02
Measure Sensor Heater Resistance

Unplug the Bank 1 Sensor 1 connector and test resistance between the two heater pins (typically 3 to 15 ohms). on the Cadillac CT5-V Blackwing equipped with 6.2L Handbuilt Supercharged LT4 V8 (668HP / 659 lb-ft / 6-Speed Manual / 10-Speed Auto).

03
Replace Upstream O2 Sensor

Use an O2 sensor socket wrench to remove the old sensor from the exhaust manifold and install an OEM-spec replacement with anti-seize on the threads. on the Cadillac CT5-V Blackwing equipped with 6.2L Handbuilt Supercharged LT4 V8 (668HP / 659 lb-ft / 6-Speed Manual / 10-Speed Auto).

Other Common Fault Codes on Cadillac CT5-V Blackwing

Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Cadillac CT5-V Blackwing:

4. Cadillac CT5-V Blackwing P0135 FAQs

What causes code P0135 to trigger on a Cadillac CT5-V Blackwing?

On the Cadillac CT5-V Blackwing (6.2L Handbuilt Supercharged LT4 V8 (668HP / 659 lb-ft / 6-Speed Manual / 10-Speed Auto)), P0135 is most frequently caused by Burnt-out internal heating element in upstream oxygen sensor or Blown O2 sensor heater fuse.

Where is the OBD-II port located on my Cadillac CT5-V Blackwing?

On the Cadillac CT5-V Blackwing, the 16-pin DLC diagnostic connector is located Driver A-pillar base kick panel. 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 CT5-V Blackwing with code P0135?

Yes, vehicle is safe to drive, but will stay in open-loop mode longer upon startup. Given that P0135 carries a Low to Medium severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.