P1133

Air/Fuel Sensor Circuit Response (Bank 1 Sensor 1)

Car Fault Codes Toyota Emissions & exhaust

Can you still drive? Yes, normally

Who can fix it? DIY with some experience

Typical repair time 30 minutes – 2 hours

Typical cost SAR 100 to 1,200

What it means

This is a Toyota-specific code; other makes may use the number differently. The engine computer tests how quickly the upstream air/fuel (A/F) sensor signal follows changes in the mixture, and found the sensor responding too slowly. The most common cause is an aged or contaminated sensor.

Models covered: Toyota models with air/fuel ratio (A/F) sensors, mainly model years around 1998–2004 (e.g. Camry, Corolla, RAV4, Highlander, Sienna, Tacoma, Tundra); later models use generic codes (P2195–P2198, P0031/P0032).

Symptoms4

Check engine light on.
Slightly higher fuel consumption.
Usually no obvious driveability symptoms.
The car may fail an emissions inspection.

Possible causes5

A/F sensor worn out with mileage.
Sensor contaminated by burnt oil, coolant or silicone.
Exhaust leak ahead of the sensor.
Weak sensor heater leaving the sensor too cool.
High resistance in the wiring or connector.

How to diagnose5

Watch the sensor on a scan tool while snapping and releasing the throttle; a slow sensor shows a late or flat change.
Check for heater codes such as P1135 and fix those first.
Look for signs of oil burning or coolant entering the combustion chamber.
Check the exhaust ahead of the sensor for leaks.
Inspect the sensor wiring and connector.

How to fix5

Repair any exhaust leak.
Fix oil burning or coolant leaks before fitting a new sensor so it is not contaminated again.
Repair wiring or the connector.
Replace the A/F sensor with a part matching the Toyota specification.
Clear the codes and drive until the sensor monitor completes.

Repair cost

0–500

500–2,000

2,000–5,000

5,000+

In Saudi riyals; the highlighted part is the expected range for this fault.

The cost is usually the sensor plus fitting; it is lower when the cause is only an exhaust leak or a connector.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions

Does P1133 harm the engine?

Not directly, but it weakens mixture control, which raises fuel use and emissions and can hurt the catalytic converter if ignored for a long time.

Why did my new sensor fail quickly?

If the engine burns oil or coolant, the new sensor gets contaminated too. Fix the root cause before replacing the sensor.

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This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.

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