P0548: Exhaust Gas Temperature Sensor Circuit Low Bank 2 Sensor 1

The exhaust gas temperature sensor is a thermistor in a voltage divider with the module's pull-up resistor; the first one (sensor 1) sits before the turbocharger, the oxidation catalyst or after it depending on the maker. Diesels use it for particulate filter regeneration and component protection; CARB names it explicitly as a monitored input. Bank 2 sensor 1 exists only on V engines with a separate exhaust path per cylinder bank. No manufacturer document available to us uses this code; the thresholds known for bank 1 apply by analogy. P0548 means the signal is below range, usually a short to ground – for bank 1 GM uses below 142 Ω, Ford below 0.10 V.

Bank 2 is the side without cylinder 1, so it only exists on V or boxer engines.

Symptoms

• Check engine light on
• Particulate filter regeneration missing, filter warning
• Possible power reduction

Most likely causes

• Signal line shorted to ground
• Sensor shorted internally
• Connector damp or corroded
• Engine module

What to check, in order

Start with the simplest. You can tick off each step.

1. Read the soot load and differential pressure with a scanner
2. With the connector unplugged, check whether the signal wire is making contact with ground.
3. Check the differential pressure sensor's hoses
4. Check the temperatures before and after the filter
5. Fix any fuel injection or EGR codes before regenerating
6. Perform a regeneration while driving or at a repair shop when the diagnosis allows it

Good to know

• Repair difficulty: medium
• It can trigger limp mode.
• It affects emissions.

What each character of P0548 means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• 5: Speed and idle
• 48: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0548?

If the light is on steadily, take a highway drive or go to a repair shop soon. If the car is in limp mode or the light is flashing, do not push the engine.

What causes code P0548?

The most common causes are: signal line shorted to ground; sensor shorted internally; connector damp or corroded.

Related codes

• P0547Exhaust Gas Temperature Sensor Circuit Bank 2 Sensor 1
• P0549Exhaust Gas Temperature Sensor Circuit High Bank 2 Sensor 1
• P0545Exhaust Gas Temperature Sensor Circuit Low Bank 1 Sensor 1
• P2035Exhaust Gas Temperature Sensor Circuit Low (Bank 2 Sensor 2)

Sources

• hella.com: checking the exhaust gas temperature sensor
• gsi.ext.gm.com: 18OBDG04 Engine Diagnostics
• fordservicecontent.com: obd summary diesel 2023
• law.cornell.edu: 13 CCR 1968.2

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.