AutoCodes – Scion – P0133 Scion

P0133 Scion Code - Heated Oxygen Sensor Circuit Slow Response Bank 1 Sensor 1

Quick Answer

The Heated Oxygen (HO2) sensor (bank 1 sensor 1) monitors the oxygen concentration in the exhaust gas. Common causes include Open or short in HO2 sensor (bank 1 sensor 1) circuit, HO2 sensor (bank 1 sensor 1), HO2 sensor heater (bank 1 sensor 1). Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: P0133 Scion indicates Heated Oxygen Sensor Circuit Slow Response Bank 1 Sensor 1.
Common causes: Common causes include Open or short in HO2 sensor (bank 1 sensor 1) circuit, HO2 sensor (bank 1 sensor 1), HO2 sensor heater (bank 1 sensor 1).
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

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Code Popularity 8,508

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 14, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code P0133 Scion Description

The Heated Oxygen (HO2) sensor (bank 1 sensor 1) monitors the oxygen concentration in the exhaust
gas. For optimum TWC operation, the air-fuel mixture must be maintained as close as possible to the
stoichiometric ratio. The HO2 sensor output voltage changes dramatically in the vicinity of the
stoichiometric ratio. By making adjustments in accordance with these signal voltages, the ECM adjusts
the fuel injection time so that the air-fuel ratio remains close to stoichiometric levels.
If the oxygen concentration in the exhaust gas increases, the air-fuel ratio is lean and the HO2 sensor
output voltage to the ECM drops below 0.45 V. If the oxygen concentration in the exhaust gas decreases,
the air-fuel ratio is rich and the HO2 sensor output voltage to the ECM increases to above 0.45 V.

OBDII Code P0133 Scion - Heated Oxygen Sensor Circuit Slow Response Bank 1 Sensor 1 - AutoCodes.com — P0133 Scion Code - Heated Oxygen Sensor Circuit Slow Response Bank 1 Sensor 1

What does this mean?

What are the Possible Causes of the DTC P0133 Scion?

Open or short in HO2 sensor (bank 1 sensor 1) circuit
HO2 sensor (bank 1 sensor 1)
HO2 sensor heater (bank 1 sensor 1)
EFI relay
Air induction system
Fuel pressure
Injector
ECM

How to Fix the DTC P0133 Scion?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

Replacing the Front Heated Oxygen Sensor Bank 1 usually takes care of the problem.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0133 Scion code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.