P0085
Fix within a few daysYour engine's computer detected an open circuit in the heater element of the downstream oxygen sensor on Bank 2.
Code P0085 means your downstream oxygen sensor on Bank 2 has a heater circuit open. Common causes: Failed O2 sensor (80%), wiring issues (15%). Drivability: Yes, for short trips only. Repair cost: $50-$250 DIY, $150-$550 professional.
Can I Drive With P0085?
Yes, for short trips only
Essential trips under 10 miles, avoid highways and heavy acceleration. Fix within a few days.
Stop driving immediately if: Flashing CEL, loud noises, burning smell, rotten egg smell, significant power loss
Symptoms of P0085
- 1Check Engine Light is on
- 2Reduced fuel economy
- 3Engine may run slightly rough (less common)
- 4Failed emissions inspection
Common Causes of P0085
Parts most likely causing this code, ranked by probability
The heater element inside the oxygen sensor has failed, creating an open circuit and preventing the sensor from reaching operating temperature.
80% of P0085 cases are fixed by replacing this part
Damaged, corroded, or loose wiring or a faulty connector prevents power from reaching the O2 sensor's heater circuit.
15% of P0085 cases are fixed by repairing wiring or connectors
A blown fuse in the O2 sensor heater circuit cuts off power to the sensor's heater.
4% of P0085 cases are fixed by replacing a fuse
A rare internal fault in the engine computer can prevent it from properly controlling or monitoring the O2 sensor heater circuit.
1% of P0085 cases are fixed by replacing the ECM/PCM
Check These First (Before Buying Parts)
- Visually inspect the Bank 2 Sensor 2 and its wiring for any obvious damage, fraying, or corrosion.
- Check the fuse for the O2 sensor heater circuit in your vehicle's fuse box. Replace if blown.
How to Diagnose P0085
- 1Visually inspect the Bank 2 Sensor 2 and its wiring for any obvious damage, corrosion, or loose connections.
- 2Locate and check the fuse for the O2 sensor heater circuit (refer to your vehicle's fuse box diagram). Replace if blown.
- 3Disconnect the Bank 2 Sensor 2 and use a multimeter to test the resistance of the heater circuit terminals on the sensor itself. Compare to factory specifications.
- 4With the sensor disconnected, use a multimeter to check for 12V power and a good ground at the vehicle's O2 sensor connector for the heater circuit.
- 5If the sensor tests bad and wiring/fuse are good, replace the Bank 2 Sensor 2.
P0085 on Popular Vehicles
Ford F-150
2004-2024On V8 F-150s, Bank 2 is the passenger side. The downstream O2 sensor is a common failure point due to heat and road debris exposure.
85% fixed by replacing the O2 sensor
Chevrolet Silverado
2007-2024Silverados with P0085 frequently have a failed heater element in the downstream O2 sensor on the driver's side (Bank 2 on many GM V8s). Check wiring carefully as well.
80% fixed by replacing the O2 sensor
Toyota Camry
2007-2024For 4-cylinder Camrys, Bank 2 does not exist, so this code would typically be P0057 (Bank 1 Sensor 2). If a V6 Camry, Bank 2 is the rear bank. O2 sensor failure is the primary cause.
90% fixed by replacing the O2 sensor
Frequently Asked Questions
What does P0085 mean?
P0085 indicates an open circuit in the heater element of your downstream oxygen sensor on Bank 2. This means the sensor isn't heating up properly to provide accurate readings.
Can I drive with P0085?
Yes, for short trips only. Your vehicle will run, but fuel economy will suffer, emissions will increase, and your catalytic converter could be damaged over time. Avoid long drives.
Will P0085 clear itself?
No, P0085 will not clear itself. The underlying electrical fault in the heater circuit requires repair. The Check Engine Light will remain on until the issue is resolved.
How do I fix P0085 myself?
Start by inspecting the sensor's wiring and checking the O2 sensor heater fuse. If those are good, test the resistance of the heater element on the Bank 2 Sensor 2 with a multimeter. If it's out of specification, replace the sensor.
How much does it cost to fix P0085?
DIY costs $50-$250 for a new oxygen sensor. A professional repair typically costs $150-$550, which includes the part and 1-2 hours of labor.
P0085 keeps coming back - why?
If P0085 returns, the replacement sensor may be faulty, there could be a persistent wiring issue not fully resolved, or in rare cases, a problem with the engine's computer.
Will P0085 fail emissions/smog test?
Yes, P0085 will cause your vehicle to fail an emissions or smog test. The O2 sensor is a critical component for monitoring and controlling emissions.
What's the difference between P0085 and P0084?
P0085 refers to an open heater circuit for Bank 2 Sensor 2 (downstream), while P0084 refers to an open heater circuit for Bank 2 Sensor 1 (upstream). Both are O2 sensor heater circuit issues on the same bank.
P0085 on Ford F-150?
P0085 on a Ford F-150, especially V8 models, often points directly to a failed downstream O2 sensor on the passenger side (Bank 2). These sensors are exposed to harsh conditions and fail over time.
Questions to Ask Your Mechanic
Did you test the resistance of the O2 sensor's heater element?
Good answer: Yes, I measured the resistance and it was out of specification, indicating an internal heater failure. I also checked the wiring for continuity.
What did you find when checking the power and ground to the O2 sensor connector?
Good answer: I confirmed there's 12V power and a solid ground at the connector, so the issue is definitely with the sensor itself or the wiring right at the sensor.
Repair Cost Estimate
DIY Repair
Parts only
$50-$250
Shop Repair
Parts + labor
$150-$550
Save $100-$300 by doing it yourself
Difficulty
intermediate
Time
1-2 hours
Intermediate - requires a multimeter for testing and an O2 sensor socket for removal/installation, which can be challenging if the sensor is seized.
Cost of Waiting
Ignoring P0085 will lead to reduced fuel economy and increased emissions. Over time, inaccurate readings from the unheated sensor can cause your engine to run rich, sending unburned fuel to your catalytic converter. This can overheat and destroy the converter, turning a $100 sensor job into a $1,000-$2,500 catalytic converter replacement.
While You're In There...
If you're removing exhaust components to access the sensor, replacing old gaskets prevents exhaust leaks and ensures a proper seal.
Applying anti-seize to the new O2 sensor threads prevents it from seizing in the exhaust pipe, making future removal much easier.
Tools You'll Need
- OBD-II scan tool
- Multimeter
- O2 sensor socket (7/8 inch or 22mm)
- Ratchet and extensions
- Wire brush (for threads)
- Anti-seize compound
P0085 is a common electrical fault for an oxygen sensor. Most repairs are straightforward, involve replacing the sensor, and will restore your vehicle's fuel economy and emissions performance.
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Your Next Steps
Step 1: Perform a thorough visual inspection of the Bank 2 Sensor 2 and its wiring. Look for any cuts, burns, or corrosion. Check the O2 sensor heater fuse.
Step 2: If the visual inspection and fuse check don't reveal the problem, use a multimeter to test the resistance of the O2 sensor's heater element and verify power and ground at the connector.
Step 3: If the sensor's heater resistance is out of specification, you'll likely need a new Bank 2 Sensor 2. Consider replacing it with a quality aftermarket or OEM part.