OBD-II trouble code
P2087: Exhaust Gas Temperature Sensor Circuit Intermittent Bank 2 Sensor 2
The furthest sensor from the module, at the end of the longest return path. That makes it the channel where a marginal shared ground breaks the rules first — so whether this code ever arrives alone is the most informative thing about it.
Quick facts
- System
- Powertrain
- Category
- Exhaust / Aftertreatment
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $120 – $900
- DIY difficulty
- Advanced DIY
Browse every code in P2000–P20E8, or start from the full code library.
What does P2087 mean?
P2087 records a momentary, unbelievable reading from the second exhaust temperature sensor on bank 2 — the last of the four addresses in the system and the one physically furthest from the module.
That distance is the key to the code, because exhaust temperature sensors on most vehicles do not each get their own private ground. They share a sensor return, and often a shared reference, that runs back to a common point at or near the module. Current from every sensor on that return flows through the same path, and every path has resistance. When the shared return is healthy the resistance is small enough to ignore. When a splice corrodes, a ground point loosens, or a connector body starts to fret, the resistance rises — and the voltage error that produces is largest at the end of the longest run. The bank 2 downstream channel is that end. So a shared problem, which is not really about this sensor at all, will push this channel outside its limits before it pushes any of the others, and the module will name the only channel it can see misbehaving.
This gives P2087 a diagnostic property the other three intermittents do not have, and it is worth more than any single measurement. Whether the code ever appears on its own is the first question to settle. P2087 alone, with no other exhaust temperature code ever stored, is a local fault: this sensor, this connector, this length of harness. P2087 appearing in company — even company that came and went months apart, even codes that cleared themselves — points instead at what all four channels share. That means the shared return, the shared reference, the common connector body, or the module's own ground. Chasing this sensor when the history contains other exhaust temperature codes is the most reliable way to spend money here without changing anything.
The second thing this position dictates is the order of work, and it is the opposite of the usual order. The rule of thumb on most sensor faults is to test at the sensor and work back. Here, the sensor is the single most expensive thing in the circuit to reach — far side of the vehicle, under the floor, frequently behind shielding, often seized into a boss that has spent years wet — while the harness run and the common ground point are comparatively easy to inspect and test. So the economical sequence is to prove the shared side first, at the module end and at the common ground, and only go to the sensor once everything cheaper has been eliminated. On the bank 1 downstream channel that order barely matters. Here it can halve the bill.
The third characteristic is how the complaint arrives. Because the fault is intermittent and the affected reading is a downstream one, drivers often do not describe a power problem at all. What they describe is a history: cleaning cycles that keep being attempted and abandoned, a warning light that comes and goes, a garage visit that found nothing, a filter warning some months later. The pattern only becomes visible when someone lays the service records and the stored history side by side, which is another reason to read the fault memory properly rather than clearing it and hoping.
With this code stored, the vehicle drives normally and nothing is being damaged directly. What is being lost is confidence in the last measurement of the aftertreatment chain, and on a vehicle with two separate paths that means one half of the system running its cycles conservatively while the other half does not.
Common causes
- Corroded or high-resistance shared sensor ground, whose voltage error shows up first on the longest return path
- Degraded splice or common connector body serving several exhaust temperature sensors
- Module-end ground point loosened or corroded behind trim or in a wheel arch
- Connector at the sensor not fully latched after aftertreatment or exhaust work, passing static tests but failing under movement
- Water and road salt ingress into a connector mounted low on the far side of the underbody
- Harness chafed against a heat shield, subframe member or driveshaft on the bank 2 path
- Lead crushed or dragged by an exhaust hanging on perished mounts
- Terminal fretting from vibration at the longest and least supported part of the run
- Internal connection cracked inside the sensor body after long thermal cycling
- Damage from underbody work, lift pads or road debris on an unprotected section
Symptoms
- Warning light that appears and clears itself, sometimes weeks apart
- A stored history containing other exhaust temperature codes that also came and went
- Repeated aftertreatment cleaning cycles attempted and abandoned over months
- Bank 2 downstream trace showing isolated dropouts or spikes the other channels do not share
- Indicated soot or ash load creeping upward on one path only
- Previous garage visits that found nothing wrong
- Momentary reading at zero or at full scale, then normal again
- Fault beginning shortly after aftertreatment, exhaust or underbody work
- Nothing reproducible during a stationary workshop test
- No hard circuit code stored, because no fault persisted long enough to set one
Diagnostic steps
- 1.Read the full fault history before touching the vehicle, including codes that have cleared. Whether this code has ever appeared alongside other exhaust temperature codes is the single most informative thing available, and clearing the memory destroys it.
- 2.If other exhaust temperature codes are in the history, investigate what all the channels share before investigating this one. A rising resistance in a common return produces its largest voltage error at the end of the longest run, which is exactly where this sensor sits.
- 3.Test the shared sensor ground under load rather than measuring continuity at rest. A voltage drop test with the circuit working will expose a marginal joint that an ohmmeter calls perfect.
- 4.Inspect the module-end common connector and ground point first. They are the cheapest parts of this circuit to reach and the most likely to explain a fault on the furthest channel.
- 5.Invert the usual order of work. The sensor is the most expensive item here to reach and the harness and grounds are the least, so eliminate everything cheaper before going near the probe.
- 6.Record the channel through a real drive with a graphing tool or min and max capture. Extremes recorded on a sensor that reads sensibly in front of you prove dropouts nobody witnessed.
- 7.Check the sensor connector is fully latched. A partially seated connector passes every static test and fails only under movement, and it is a common outcome of aftertreatment work on this path.
- 8.Follow the bank 2 underbody run for chafe against heat shields, subframe members and driveshafts, and check the exhaust hangers that keep the system from swinging into it.
- 9.Flex short sections of the harness individually while watching a live trace, so a positive result localises the fault rather than merely confirming one exists.
- 10.After any repair, confirm the result against the vehicle's own history — a cleaning cycle that now completes, where previous ones abandoned, is better evidence than a clear scan at the end of the job.
Repair cost
$120 – $900
Diagnosis is $140 to $260, because the history has to be read properly and the shared circuit tested under load rather than at rest. Cleaning and remaking a corroded shared ground or splice is $80 to $280 and is the outcome that fixes the largest share of these. Repairing a chafed or crushed underbody section and restoring clips is $110 to $320. Replacing perished exhaust hangers is $60 to $220. The sensor itself is $60 to $320 in parts with 0.6 to 2.5 hours of labour, the highest of the four positions, and more again if it has seized into a boss on the far side of a wet underbody.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with exhaust gas temperature (egt) sensor replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an advanced DIY job. It typically requires specialty tools, scan-tool access, lifting equipment, or careful sequencing to avoid causing new failures. Plan for extended downtime and have a backup vehicle. Most owners are better served by a shop that has done this repair before.