P2489: Exhaust Gas Temperature Sensor Circuit Intermittent/Erratic (Bank 2 Sensor 5)

P2489 points to an unsteady signal from the fifth exhaust probe on bank 2: the value stays within its electrical limits but jumps or drops out briefly. This code is not documented by any manufacturer, as no public layout carries five probes per bank on a twin-bank engine. For the bank 1 position GM shows the method under P2484: samples every 100 ms are compared, and in 2025 a step above 100 °C in 12 of 25 samples, valid only between 140 and 1070 °C, sets a Type B fault. CARB requires monitoring of inputs for erratic behaviour where it affects emissions. Such faults usually come from loose terminals or a harness that touches hot parts, so a careful check of routing and clips pays off.

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

Symptoms

• Warning lamp coming and going
• Jumping value in live data

Most likely causes

• Loose terminal in the connector
• Harness touching hot exhaust parts
• Internal crack in the probe

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. Gently move the wiring with the engine running and watch whether the reading changes.
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 affects emissions.

What each character of P2489 means

• P: Powertrain: engine and transmission
• 2: Generic code: same on every make
• 4: Emissions
• 89: Specific fault in that system

Frequently asked questions

Can I keep driving with code P2489?

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 P2489?

The most common causes are: loose terminal in the connector; harness touching hot exhaust parts; internal crack in the probe.

Related codes

• P2484Exhaust Gas Temperature Sensor Circuit Intermittent/Erratic (Bank 1 Sensor 5)
• P2485Exhaust Gas Temperature Sensor Circuit/Open (Bank 2 Sensor 5)
• P2486Exhaust Gas Temperature Sensor Circuit Low (Bank 2 Sensor 5)
• P2487Exhaust Gas Temperature Sensor Circuit High (Bank 2 Sensor 5)
• P2488Exhaust Gas Temperature Sensor Circuit Range/Performance (Bank 2 Sensor 5)

Sources

• law.cornell.edu: 13 CCR 1968.2
• gsi.ext.gm.com: 25OBDG04A

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.