P043D: Catalyst Temperature Sensor Circuit High (Bank 2 Sensor 2)

What it means

Catalyst temperature sensor at bank 2 sensor 2 above upper plausibility — open signal or short to B+.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The catalyst temperature sensor at bank 2, sensor 2 reports exhaust catalyst temperature from the engine’s second bank. P043D sets when the control module sees a signal higher than plausible, often from an open signal wire or a short to battery power.

Common causes

Most likely first.

1. Open signal line
2. Connector pins corroded - high contact resistance
3. Supply wire pinched against B+ source

Symptoms

• Check engine light on
• Failed emissions inspection
• Possibly slightly increased fuel consumption
• Sulfur (rotten egg) smell from exhaust under load

How to diagnose it

1. Confirm P043D and review the freeze-frame and live data to see whether the bank 2 sensor 2 reading is unusually high or fixed.
2. With the exhaust cool, inspect the sensor connector for disconnection, corrosion, damaged pins, or a terminal that has backed out.
3. Follow the bank 2 sensor 2 harness and check for a break, heat damage, or insulation pinched against a powered wire.
4. Use the vehicle wiring diagram to check for an open signal path and a short to power, and verify connector contact.
5. If the circuit checks out, test the sensor against the manufacturer's specification before suspecting the control module.

Common fixes

• Reconnect and secure the bank 2 sensor 2 connector.
• Repair an open signal wire or insulation damaged by heat or pinching.
• Replace damaged connector terminals and restore their proper fit.
• Replace the sensor if it fails testing with a sound circuit.

Can I keep driving?

The fault generally does not trigger limp mode, but it can disrupt catalyst temperature monitoring and cause an emissions inspection failure. Limit heavy loads if a sulfur smell appears and arrange diagnosis soon.