Engine Temperature Sensor Circuit
This code indicates a problem with the engine temperature sensor circuit.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The engine temperature sensor measures the coolant temperature, typically around 190-220°F (88-104°C). If it's faulty, it can send bad data to the engine computer, affecting performance and emissions.
What the computer is actually seeing
The engine control module (ECM) expects voltage readings from the temperature sensor to be between 0.5V (cold) and 4.5V (hot). If readings are outside of this range or show open/short circuits, the code will trigger.
What a healthy reading looks like
Coolant temp around 190-220°F (88-104°C) with corresponding voltages between 0.5V and 4.5V.
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.
- 1Check coolant level; it should be full. If low, top it off and recheck.
- 2Inspect the wiring and connectors to the engine temperature sensor for damage or corrosion. Repair as necessary.
- 3Measure the voltage at the engine temperature sensor connector with the engine running. Expect 0.5V (cold) to 4.5V (hot). If out of range, replace the sensor.
- 4If voltage is normal but the code persists, swap the engine temperature sensor with a known good one, then clear the code and retest.
Common causes
- Faulty engine temperature sensor
- Wiring issues or bad connectors
- Coolant leaks affecting readings
Typical repair cost
$$
Related codes
Frequently asked questions
Can I drive with this code active?
Yes, but drivability may be affected. It's recommended to fix it soon.
Will this code come back after clearing it?
If the underlying issue isn't resolved, yes, the code will likely return.
Why do I see this code with SPN 315?
SPN 315 is related to temperature readings; they often trigger together due to sensor or wiring issues.
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