A failing EGT sensor on bank 1 sensor 2 that has an internal intermittent connection or cracked element.; Damaged or chafed wiring between the sensor and the PCM, often near hot exhaust components or sharp brackets.; Corroded, loose, or water-intruded connector pins at the sensor or PCM harness.; A poor ground connection for the sensor circuit, causing a floating reference voltage.; Exhaust leaks upstream of the sensor that allow outside air to pulse across the sensing element.; A PCM with an intermittent internal driver or analog-to-digital fault on that input channel.; Aftermarket or incorrectly installed exhaust components that place the sensor in a different temperature zone.

DTC codes / P20xx · Fuel and air metering and auxiliary emission controls / P2085

P2085Exhaust Gas Temperature Sensor Circuit Intermittent (Bank 1 Sensor 2)

P2085 means the powertrain control module (PCM) has seen the exhaust gas temperature (EGT) sensor on bank 1 sensor 2 report a signal that cuts in and out intermittently, rather than failing completely. The PCM monitors this sensor's voltage or resistance over time and flags the code when the reading jumps, drops out, or becomes erratic beyond a calibrated window for a set number of drive cycles.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering and auxiliary emission controls

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms.
Intermittent hesitation or slight loss of power under load when the sensor signal drops out.
A momentary surge or stumble during acceleration if the PCM defaults to a substitute value.
Reduced fuel economy if the fault causes the PCM to run a richer default strategy.
A pending P2085 that appears and clears on its own over several drive cycles.
In rare cases, a rough idle or elevated exhaust temperatures if the PCM misreads the sensor signal.

Common causes, most likely first

A failing EGT sensor on bank 1 sensor 2 that has an internal intermittent connection or cracked element.
Damaged or chafed wiring between the sensor and the PCM, often near hot exhaust components or sharp brackets.
Corroded, loose, or water-intruded connector pins at the sensor or PCM harness.
A poor ground connection for the sensor circuit, causing a floating reference voltage.
Exhaust leaks upstream of the sensor that allow outside air to pulse across the sensing element.
A PCM with an intermittent internal driver or analog-to-digital fault on that input channel.
Aftermarket or incorrectly installed exhaust components that place the sensor in a different temperature zone.

How to diagnose and fix it

Scan all modules and record freeze-frame data for P2085, then clear the code and road-test to confirm it returns.
Visually inspect the bank 1 sensor 2 EGT sensor, its connector, and the harness routing for chafing, heat damage, or corrosion.
Back-probe the sensor signal and ground wires at the connector and wiggle the harness while watching live data for dropouts.
Measure sensor resistance or voltage against the manufacturer's specification at ambient and operating temperature.
Check for exhaust leaks and verify the sensor is the correct part and is threaded fully into the bung.
If the harness and sensor check out, perform a continuity and load test on the signal and ground circuits back to the PCM.
Replace the EGT sensor only after confirming the circuit is sound, then clear codes and verify the repair with a long road test.

Intermittent EGT faults that fool good technicians

A sensor that tests perfectly on a cold bench can still fail intermittently when the exhaust reaches operating temperature, so always test the circuit hot and with the engine under load.
Chafed wiring hidden behind heat shields or inside a split loom is a more common cause of P2085 than a failed sensor, and a wiggle test with live data visible is the fastest way to expose it.
The PCM may substitute a fixed default exhaust temperature when the signal drops out, which can mask driveability symptoms and make the fault look harmless until the sensor fails completely.
An exhaust leak just ahead of the sensor can create temperature pulsations that mimic an intermittent sensor, so a smoke test of the exhaust is a worthwhile cheap check before replacing parts.
Clearing P2085 without checking freeze-frame data can send you chasing the wrong bank or sensor if a related code such as P2086 or P2087 is also pending.

Can I keep driving with P2085?

You can usually drive with P2085 because the PCM has default strategies, but avoid heavy towing or sustained high-load driving until it is repaired. If the check engine light starts flashing or you notice a significant power loss, stop driving and have it diagnosed promptly.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.