P0130 Toyota 4Runner
O2 Sensor Circuit Malfunction (Bank 1, Sensor 1) · Powertrain Code · Medium · Repair: Moderate
What is P0130?
The upstream oxygen sensor on bank 1 is not functioning correctly, affecting fuel mixture control.
When the Toyota 4Runner triggers code P0130 (o2 sensor 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 Toyota 4Runner.
This repair is rated moderate, meaning some experience and specialty tools required.
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 Toyota 4Runner.
Common Causes on Toyota 4Runner
- Bank 1 Sensor 1 oxygen sensor circuit malfunction — common on high-mileage Toyota VVT-i engines
- Denso upstream O2 sensor heater element failed
- Exhaust leak before the upstream O2 sensor
- Wiring harness damage from heat shield contact
Symptoms
- Check Engine Light on
- Decreased fuel economy (3-5 MPG)
- Slight rough idle
- Failed emissions test
Notes for Toyota 4Runner
Always use Denso OE oxygen sensors on Toyota — aftermarket universal sensors frequently cause driveability issues and repeat codes.