Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P0117
DTC P0117 : ECT Sensor 1 Circuit Low Voltage
NOTE: Before you troubleshoot, review the general troubleshooting information .
| DTC Description | Confirmed DTC | Pending DTC | Freeze Frame |
|---|---|---|---|
| P0117 ECT Sensor 1 Circuit Low Voltage |
DTC (PGM-FI)
- Problem verification
-1. Turn the vehicle to the ON mode.
-2. Check the parameter (s) below with the HDS.
Signal Threshold Current conditions Values Unit Values Unit ECT SENSOR 1 Less than 0.08 V Do the current condition (s) match the threshold?
YES
The failure is duplicated. Go to step 2.
NO
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at ECT sensor 1 and the PCM. If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot .
- ECT sensor 1 performance check
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Disconnect the following connector.
ECT sensor 1 2P connector -3. Turn the vehicle to the ON mode.
-4. Check the parameter (s) below with the HDS.
Signal Threshold Current conditions Values Unit Values Unit ECT SENSOR 1 Less than 0.08 V Do the current condition (s) match the threshold?
YES
Go to step 3.
NO
- Shorted wire check (TW line)
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Jump the SCS line with the HDS.
-3. Disconnect the following connector.
PCM connector C (51P) -4. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode ECT sensor 1 2P connector: disconnected PCM connector C (51P): disconnected Test point 1 ECT sensor 1 2P connector No. 1 Test point 2 Body ground Is there continuity?
YES
Repair a short in the TW wire between the PCM (C41) and ECT sensor 1.
NO
The TW wire is OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM , then recheck. If DTC P0117 goes away and the PCM was updated, troubleshooting is complete. If DTC P0117 goes away and the PCM was substituted, replace the original PCM .
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.