P0135 on Toyota Grand 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 Grand Highlander (2024–2026, 2.4L Turbo / 2.5L Hybrid / Hybrid MAX 362HP Turbo AWD).
1. Symptoms of P0135 on Toyota Grand Highlander
When the Engine Control Module (ECM/PCM) on your Toyota Grand Highlander (2.4L Turbo / 2.5L Hybrid / Hybrid MAX 362HP Turbo AWD) logs fault code P0135, drivers commonly observe:
2. Most Likely Causes on Toyota Grand Highlander
Historical warranty claims and technical repair bulletins for Toyota Grand Highlander point to the following failure distribution:
3. Step-by-Step DIY Repair Guide for Toyota Grand Highlander
Locate the under-hood fuse box and test the O2 sensor heater fuse with a multimeter or test light. on the Toyota Grand Highlander equipped with 2.4L Turbo / 2.5L Hybrid / Hybrid MAX 362HP Turbo AWD.
Unplug the Bank 1 Sensor 1 connector and test resistance between the two heater pins (typically 3 to 15 ohms). on the Toyota Grand Highlander equipped with 2.4L Turbo / 2.5L Hybrid / Hybrid MAX 362HP Turbo AWD.
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 Grand Highlander equipped with 2.4L Turbo / 2.5L Hybrid / Hybrid MAX 362HP Turbo AWD.
Other Common Fault Codes on Toyota Grand Highlander
Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Toyota Grand Highlander:
4. Toyota Grand Highlander P0135 FAQs
What causes code P0135 to trigger on a Toyota Grand Highlander?
On the Toyota Grand Highlander (2.4L Turbo / 2.5L Hybrid / Hybrid MAX 362HP Turbo AWD), 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 Grand Highlander?
On the Toyota Grand Highlander, the 16-pin DLC diagnostic connector is located Driver side lower knee panel above dead pedal. 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 Grand 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.