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 P0116: Engine Coolant Temperature Sensor Circuit, Range/Performance Problem
2004 Acura 3.5RLSECTION DTC P0116: Engine Coolant Temperature Sensor Circuit, Range/Performance Problem
WARNING: This page is about a different car, the 2003 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
When substituting or replacement of PCM is recommended, see PCM REMOVAL & REPLACEMENT
for important precautions.
- Turn ignition on. Using Honda PGM Tester or the HDS, check ECT sensor in the DATA list. If ECT reading is about 176°F (80°C) or higher, 0.86 volt or less, go to next step. If ECT reading is not about 176°F (80°C) or higher, 0.86 volt or less, go to step 3 .
- Note current coolant temperature. Turn ignition off. Cool engine for one hour. Using Honda PGM Tester or the HDS, check ECT sensor in the DATA list. If ECT reading changes 5.4°F (3°C) or more, problem is intermittent, system is OK at this time. Check thermostat and cooling system. If ECT reading changes 5.4°F (3°C) or more, go to step 4 .
- Note current coolant temperature. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle. Using Honda PGM Tester or the HDS, check ECT sensor in the DATA list. If ECT reading changes 5.4°F (3°C) or more, problem is intermittent, system is OK at this time. Check thermostat and cooling system. If ECT reading changes 5.4°F (3°C) or more, go to step 4 .
- Turn ignition off. Replace the ECT sensor. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See PCM IDLE LEARN PROCEDURE .
- Allow engine to cool to between 17°F (-7°C) and 86°F (30°C).
- Start engine, let idle for 20 minutes.
- Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0116 is set, check for poor connections or loose terminals at ECT sensor and PCM harness connectors. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, go to next step.
- Monitor the OBD STATUS for DTC P0116 in the DTCs menu with the Honda PGM tester or the HDS. If it PASSED, troubleshooting is complete. If it is FAILED, check for poor connections or loose terminals at MAP sensor and PCM harness connectors. Go to step 1 . If it is NOT COMPLETED, go to step 5 and recheck.
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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.