OBD-II Code · Sensors
P2031
Exhaust Gas Temperature Sensor Circuit Bank 1 Sensor 2
Severity
medium
Worth booking. It costs fuel, emissions or comfort until it is fixed.
Can you drive it
Only if running normally
A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety.
Indicative cost (USD)
$150–$500
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
EGT sensor circuit fault.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Likely causes
- Failed EGT sensorMost common
- Wiring
Read the full diagnostic procedureP2031 means the post-DPF exhaust gas temperature sensor (commonly EGT 12 or EGT 13 depending on layout) is reporting a voltage outside the ECM's expe…
P2031 means the post-DPF exhaust gas temperature sensor (commonly EGT 12 or EGT 13 depending on layout) is reporting a voltage outside the ECM's expected 0.2 to 4.8 V window or has gone open circuit, which immediately disables active regen because the ECM cannot trust regen completion temperature.
Cheapest-first ladder
- unplug the sensor and back-probe the harness for 5 V reference and clean ground (under 0.1 V drop), then ohm the sensor cold (typical NTC EGT reads 200 to 400 kOhm at 20 C and drops to under 200 ohm at 600 C); if the harness is good and resistance is open or stuck, the sensor itself is the failure.
- Compare its live reading to the upstream EGT at idle on a cold start - the two should be within 30 C of each other and within 100 C of intake air temp before the engine warms.
- Caveat: the sensor wires run along the turbo heat shield on most platforms and chafe through, so always inspect the full harness run before condemning the sensor.
Vehicle-specific patterns2008 to 2010 Ford 6.4L Powerstroke chronically fail the EGT 13 (post-DPF) sensor from thermal cycling during regen, covered by Ford TSB 09-25-7; 2007…
- 2008to 2010 Ford 6.4L Powerstroke chronically fail the EGT 13 (post-DPF) sensor from thermal cycling during regen, covered by Ford TSB 09-25-7; 2007.5 to 2012 Dodge Ram 6.7L Cummins fail the downstream EGT sensor when its pigtail melts against the DPF heat shield, fixed by Mopar TSB 11-002-13;
- 2011to 2016 Duramax LML sets P2031 when the EGT 4 sensor (post-DPF) corrodes internally from condensation;
- 2010to 2015 VW/Audi 3.0 TDI fail the post-DPF EGT from soot fouling.
Estimated repair$90 to $480.
Look up another code
P2031 — frequently asked
What does a P2031 code mean?
EGT sensor circuit fault.
What causes a P2031 code?
Common causes: Failed EGT sensor; Wiring.
What are the symptoms of a P2031 code?
Typical symptoms: Check engine light.
Is it safe to drive with a P2031 code?
Only if running normally. A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety. Estimated repair: $150-$500.
How do I diagnose a P2031 code?
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
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