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P0135ToyotaToyota Highlander HubAll Toyota P0135Low to Medium Severity

P0135 on Toyota Highlander: Fix & DLC Location

Factory diagnostic troubleshooting wire for fault code P0135 (O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)) specifically on the Toyota Highlander (2020–2026, 2.4L Turbo 4-Cyl (T24A-FTS 265HP) / 3.5L V6 / 2.5L Hybrid).

Toyota Highlander
DIY Parts Estimate
$80 - $240 (DIY Sensor: $45)
Highlander OEM Fitment
Shop Labor Quote
$180 – $380
Based on $110/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 Toyota Model:
Toyota CamryToyota Camry HybridToyota Camry TRDToyota CorollaToyota RAV4Toyota HighlanderToyota Grand HighlanderToyota TacomaToyota TundraToyota 4RunnerToyota CrownToyota PriusToyota Land Cruiser

1. Symptoms of P0135 on Toyota Highlander

When the Engine Control Module (ECM/PCM) on your Toyota Highlander (2.4L Turbo 4-Cyl (T24A-FTS 265HP) / 3.5L V6 / 2.5L Hybrid) logs fault code P0135, drivers commonly observe:

Check Engine Light on on Toyota Highlander (2.4L Turbo 4-Cyl (T24A-FTS 265HP) / 3.5L V6 / 2.5L Hybrid)
Slightly increased fuel consumption on short trips on Toyota Highlander (2.4L Turbo 4-Cyl (T24A-FTS 265HP) / 3.5L V6 / 2.5L Hybrid)
Failed state emissions inspection on Toyota Highlander (2.4L Turbo 4-Cyl (T24A-FTS 265HP) / 3.5L V6 / 2.5L Hybrid)
Toyota Highlander OBD-II Port Location
The 16-pin diagnostic connector is located Under driver steering column near kick panel. Plug in your scan tool to verify freeze-frame sensor values.

2. Most Likely Causes on Toyota Highlander

Historical warranty claims and technical repair bulletins for Toyota Highlander point to the following failure distribution:

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

3. Step-by-Step DIY Repair Guide for Toyota Highlander

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 Toyota Highlander equipped with 2.4L Turbo 4-Cyl (T24A-FTS 265HP) / 3.5L V6 / 2.5L Hybrid.

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 Toyota Highlander equipped with 2.4L Turbo 4-Cyl (T24A-FTS 265HP) / 3.5L V6 / 2.5L Hybrid.

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 Toyota Highlander equipped with 2.4L Turbo 4-Cyl (T24A-FTS 265HP) / 3.5L V6 / 2.5L Hybrid.

Other Common Fault Codes on Toyota Highlander

Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Toyota Highlander:

4. Toyota Highlander P0135 FAQs

What causes code P0135 to trigger on a Toyota Highlander?

On the Toyota Highlander (2.4L Turbo 4-Cyl (T24A-FTS 265HP) / 3.5L V6 / 2.5L Hybrid), 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 Toyota Highlander?

On the Toyota Highlander, the 16-pin DLC diagnostic connector is located Under driver steering column near 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 Toyota Highlander 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.