Engine Exhaust Temperature Sensor 2 Circuit Low
The control unit detects a low input from the second exhaust temperature sensor.
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What it means (plain English)
The exhaust temperature sensor 2 is supposed to send a voltage between 0.5V and 4.5V when the engine is running. If it drops below 0.5V, the computer sees this as a problem, thinking the sensor may be faulty or there's a wiring issue.
What the computer is actually seeing
The Engine Control Module (ECM) sees a consistent voltage drop from the exhaust temperature sensor 2, indicating it's outside the normal operational range.
What a healthy reading looks like
Exhaust temperature sensor output should typically read between 0.5V (cold engine) and 4.5V (hot engine) depending on exhaust temperature.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check the wiring and connectors to exhaust temperature sensor 2 for damage or corrosion. If found, repair or replace.
- 22. Measure the voltage at the sensor connector. A reading below 0.5V indicates a fault; if within range, the issue might be on the ECM side.
- 33. If the voltage is low, swap the sensor with another one known to be working. Check if the code clears; if so, replace the sensor.
- 44. If the problem remains, inspect the wiring loom between the sensor and ECM for shorts or opens, and repair as necessary.
- 55. If wiring checks out, test the ECM to confirm it's functioning correctly.
Common causes
- Faulty exhaust temperature sensor 2
- Wiring issues or broken connectors
- Corrosion at connections or within the harness
- Faulty ECM
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's generally drivable, but fix it soon to avoid potential engine damage.
Will this code come back after clearing?
It can return if the underlying issue isn’t resolved, particularly if the sensor or wiring is faulty.
Why does this code sometimes pair with SPN 1946?
SPN 1946 indicates a high reading, so simultaneous codes suggest issues with the sensor or its circuit.
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