P2084: Exhaust Gas Temperature Sensor Circuit Range/Performance (Bank 1 Sensor 2)

P2084 applies the plausibility check to the second exhaust temperature sensor on bank 1, on diesels usually the one behind the oxidation catalyst or ahead of the particulate filter or SCR stage. GM runs the same tests here as for sensor 1: a heat balance on the 6.6 L Duramax (15OBDG09) and a cold-soak rise check on the 3.0 L LZO (25OBDG04B), both Type B. On the Ford 6.7 L diesel, P2084 sits next to P2080 in the sensor-to-sensor check that runs after 6 h off. VW's 2014 Touareg TDI is stricter in one direction only and fails sensor 2 once it reads more than 100 K below its model. Deutz stores the plausibility fault of the sensor ahead of the SCR catalyst as P2084-62 or -64 on its EMR L1 controller. A wrong value here can upset DEF dosing and regeneration control. Unsteady readings fall under P2085.

Bank 1 is the side of the engine with cylinder 1. Inline engines only have this bank.

Symptoms

• Engine warning lamp on
• Particulate filter regeneration or DEF dosing restricted
• Reduced engine power on some diesels

Most likely causes

• Sensor 2 reads low or responds slowly due to ageing or soot
• Sensor connectors swapped with another exhaust temperature sensor after repair
• Oxidation catalyst not producing the expected heat, so the reading looks implausible

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. Compare the reading with other engine data while varying the engine speed.
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 P2084 means

• P: Powertrain: engine and transmission
• 2: Generic code: same on every make
• 0: Subsystem depends on the code range
• 84: Specific fault in that system

Frequently asked questions

Can I keep driving with code P2084?

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 P2084?

The most common causes are: sensor 2 reads low or responds slowly due to ageing or soot; sensor connectors swapped with another exhaust temperature sensor after repair; oxidation catalyst not producing the expected heat, so the reading looks implausible.

Related codes

• P2080Exhaust Gas Temperature Sensor Circuit Range/Performance (Bank 1 Sensor 1)
• P2085Exhaust Gas Temperature Sensor Circuit Intermittent (Bank 1 Sensor 2)
• P2086Exhaust Gas Temperature Sensor Circuit Range/Performance (Bank 2 Sensor 2)
• P2031Exhaust Gas Temperature Sensor Circuit (Bank 1 Sensor 2)
• P2032Exhaust Gas Temperature Sensor Circuit Low (Bank 1 Sensor 2)
• P2033Exhaust Gas Temperature Sensor Circuit High (Bank 1 Sensor 2)

Sources

• gsi.ext.gm.com: 15OBDG09 Engine Diagnostics
• gsi.ext.gm.com: 25OBDG04B
• static.nhtsa.gov: MC 10074008 2280
• serdia.deutz.com: DTCList EMRL1 MainECU EN

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.