P0546: Exhaust Gas Temperature Sensor Circuit High Bank 1 Sensor 1

What it means

The exhaust gas temperature sensor signal at bank 1, sensor 1 is above the upper diagnostic threshold. Typically open circuit or short to power.

At a glance

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

How it works

Bank 1 Sensor 1 is the exhaust gas temperature sensor at the first monitored position on the Bank 1 exhaust side. P0546 sets when its signal exceeds the upper diagnostic threshold, which can result from an internally open sensor, a disconnected circuit, or wiring that drives the signal high.

Common causes

Most likely first.

1. Sensor open internally
2. Wiring open or disconnected

Symptoms

• Check-engine light on
• Possible reduced engine power or altered exhaust-system operation

How to diagnose it

1. Record freeze-frame data and check whether Bank 1 Sensor 1 live data is unusually high or fixed at an implausible value.
2. With the exhaust cool, inspect the Bank 1 Sensor 1 connector for disconnection, loose pins, corrosion, or heat damage.
3. Trace the sensor harness for breaks or an open circuit, paying attention to sections near hot exhaust components.
4. Use the wiring diagram to test the signal circuit for an open or short to power and compare results with the manufacturer's procedure.
5. Test the sensor itself and confirm that its reading changes plausibly after the circuit fault is corrected.

Common fixes

• Reconnect a loose or disconnected Bank 1 Sensor 1 connector.
• Repair an open or heat-damaged section of sensor wiring.
• Replace the Bank 1 Sensor 1 sensor if it is internally open on testing.
• Repair a signal wire shorted to power or a failed connector terminal.

Can I keep driving?

Limit driving if power is reduced or exhaust-system operation has changed, and avoid heavy loads or sustained high speeds. A signal stuck high can prevent reliable exhaust temperature monitoring.