P2085 — Exhaust Gas Temperature Sensor Circuit Intermittent #

The description of this Diagnostic Trouble Code (DTC) may vary depending on the vehicle manufacturer. Always refer to your specific OEM (Original Equipment Manufacturer) documentation for the official wording.

Known description variations:

• Exhaust Gas Temperature Sensor 2 Circuit Intermittent (Ford)
• EGT Sensor Circuit Intermittent Bank 1 Sensor 2 (GM/Chevrolet)
• Exhaust Temp Sensor B Circuit Intermittent (Mercedes-Benz)
• Exhaust Gas Temperature Sensor “B” Circuit Intermittent (Volkswagen/Audi)
• Exhaust Gas Temp Sensor Circuit Intermittent (Toyota)

Code P2085 Summary #

Code P2085 signals that the Engine Control Module (ECM)—the vehicle’s main computer—has detected an intermittent fault in the electrical circuit of an Exhaust Gas Temperature (EGT) sensor. The EGT sensor plays a crucial role in monitoring exhaust temperatures, especially for vehicles equipped with advanced emission control systems like Diesel Particulate Filters (DPF). An “intermittent” fault means the issue comes and goes, making it more challenging to pinpoint. If ignored, this code can lead to emission system inefficiency, possible damage, or even limp mode. Prompt and precise diagnosis is key to maintaining both performance and compliance.

Frequent Symptoms for Code P2085 #

When code P2085 is stored, you may notice subtle or more obvious changes in your vehicle’s behavior. Sometimes, there are no noticeable symptoms, but often, the following issues may arise:

• Check Engine Light (CEL) illuminated on the dashboard
• Reduced engine performance or power (especially during acceleration)
• Poor fuel economy
• Regeneration issues with the Diesel Particulate Filter (for diesel vehicles)
• Intermittent rough idling or hesitation
• Occasional increase in exhaust smoke

Probable Causes for Code P2085 #

P2085 is most often triggered by issues affecting the EGT sensor’s signal integrity. The following are the most common root causes, ranked by their likelihood:

1. Faulty or failing EGT sensor (worn out, internal short/open)
2. Intermittent wiring or connector issues (corrosion, loose pins, broken wires)
3. ECM or PCM software glitches (rare, but possible after updates or voltage spikes)
4. Exhaust leaks near the sensor (causing incorrect readings)
5. Aftermarket modifications disrupting OEM sensor operation

Step-by-Step Diagnostic for Code P2085 #

Proper diagnosis ensures you fix the real problem, not just the symptoms. Follow these steps to systematically check the system:

• 1. Confirm the code using a professional OBD-II scanner. Note any other related codes.
• 2. Visually inspect the EGT sensor and its wiring for physical damage, corrosion, or loose connections.
• 3. Perform a wiggle test on the harness with the engine running—if the code resets or the CEL flickers, suspect wiring or connector issues.
• 4. Check sensor resistance with a multimeter (compare to OEM specifications).
• 5. Inspect for exhaust leaks near the sensor—look for soot marks or unusual smells.
• 6. If all else checks out, consider software updates or ECM issues (rare).

Possible Repairs for Code P2085 #

Depending on your diagnostic findings, the following repairs are commonly performed to resolve P2085:

• Replace the faulty EGT sensor (most frequent solution)
• Repair or replace damaged wiring/connectors (clean terminals, fix broken wires, secure connections)
• Seal exhaust leaks near the sensor if present
• Update or reflash the ECM/PCM if a software bug is confirmed
• Restore any modified components to OEM specification

Is It Safe to Drive with Code P2085? #

Limited—You can often drive with P2085 for a short period, but it is not recommended for extended use. While the engine might run, emission controls can be compromised. If you notice reduced power, increased smoke, or other side effects, minimize driving and schedule repairs as soon as possible to avoid further damage, potential limp mode, or costly DPF/engine repairs.

Vehicles Most Commonly Affected by Code P2085 #

P2085 is seen most frequently on diesel vehicles and models equipped with advanced emission systems. The following makes and models are most often reported with this code:

• Ford (F-Series trucks, Transit, Super Duty diesels)
• Chevrolet/GMC (Silverado, Sierra, Duramax-equipped models)
• Volkswagen/Audi (TDI engines)
• Mercedes-Benz (Sprinter, BlueTEC diesels)
• Ram (1500/2500/3500 with diesel engines)
• Toyota (Land Cruiser, Hilux diesel variants)

Common Mistakes & Best Practices with Code P2085 #

Misdiagnosis or skipping steps can lead to wasted time and money. Here’s how to avoid classic pitfalls:

• Replacing the EGT sensor without checking wiring/connectors first
• Ignoring exhaust leaks that skew sensor readings
• Overlooking software updates or TSBs (Technical Service Bulletins) from the OEM
• Assuming one EGT sensor location—always verify the correct sensor (“B,” Bank 1, etc.) per OEM diagram
• Neglecting to clear the code and road test after repair

Quick FAQ for Code P2085 #

Have more questions? Here are fast answers to common concerns:

• Q: Can I clear code P2085 myself?
  A: Yes, with an OBD-II scanner. However, if the issue isn’t fixed, the code will return.
• Q: Will P2085 cause my car to fail emissions testing?
  A: Most likely, yes. Active emission-related fault codes generally result in a failed inspection until properly repaired.
• Q: Are EGT sensors expensive to replace?
  A: EGT sensors are moderately priced, but labor costs can vary depending on accessibility. Always use OEM or high-quality parts for reliability.