P0135 Nissan Pathfinder
O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1) · Powertrain Code · Low · Repair: Easy
What is P0135?
The heater circuit in the upstream O2 sensor on bank 1 has failed, delaying sensor warm-up.
When the Nissan Pathfinder triggers code P0135 (o2 sensor heater circuit malfunction (bank 1, sensor 1)), it typically points to an issue in the powertrain system. Below you'll find the most common causes, symptoms, and repair options specific to the Nissan Pathfinder.
This repair is rated easy, meaning basic tools, no lift needed.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Nissan Pathfinder.
Common Causes on Nissan Pathfinder
- Burned-out A/F ratio sensor heater element
- Blown sensor heater fuse or relay in the IPDM (Intelligent Power Distribution Module)
- Corroded sensor connector from moisture exposure
- IPDM relay failure (common Nissan issue)
Symptoms
- Check Engine Light on
- Extended warmup before closed-loop operation
- Slightly rich running when cold
- Failed emissions test
Notes for Nissan Pathfinder
Check the IPDM (fuse/relay box) first; Nissan IPDMs are known for relay failures that affect O2 heater circuits.