P0434 Catalyst temperature sensor: too low (heated catalyst, bank 2)

By: Diagno editorial team · Updated: 2026-10-15

P0434 means: Catalyst temperature sensor: too low (heated catalyst, bank 2). The exhaust pressure or temperature sensor tells the computer the exhaust gas pressure or temperature. Drive gently and have the car checked soon. The repair usually costs about €60–300 in Estonia. The most common cause: sensor damaged by heat.

What it means

The exhaust pressure or temperature sensor tells the computer the exhaust gas pressure or temperature. The turbo, particulate filter and emission cleaning are controlled by it. Bank 2 is the side of a V engine without cylinder 1.

What you may notice

• Engine light on
• Particulate filter regeneration doesn't start
• The car may go into limp mode

What could be wrong

1. 1Sensor damaged by heat
2. 2Sensor hose blocked or cracked
3. 3Wire or connector damaged by heat
4. 4Engine computer fault (rare)

Repair difficulty: Easy

What you can check yourself

Check that the sensor hoses are intact and fitted the right way round. You can do the simpler checks yourself.

How we fix it

1. We read the sensor on the diagnostic tool and compare it with other sensors
2. We check the connector, supply and ground
3. We repair the wiring or replace the sensor

Standard SAE description: Heated Catalyst Temperature Below Threshold (Bank 2)