P0116Generic code

P0116 Code: Engine Coolant Temperature Circuit Range/Performance

The P0116 code means the ECT sensor reading is electrically valid but does not agree with the other sensors. It is usually caused by a sensor that reads wrong or gets stuck, although it can also be a real condition in the engine.

Severity
Medium
Can I keep driving?
Yes, but with caution
Estimated cost
$15 to $250
Difficulty
Easy
System
Air and Fuel
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

On this page

What the P0116 code means

The engine coolant temperature (ECT) sensor sits in the cylinder head or in the thermostat housing, in contact with the coolant. The computer relies on it because it decides cold enrichment, idle speed, when to enter closed loop, the radiator fan and, on automatic transmissions, torque converter lockup.

In this case the signal is within the electrical limits, but it is not believable. The computer compares the ECT with other data. With a cold engine after a full night, the ECT should match the IAT, and after starting, the temperature should climb steadily to 85 to 105 °C (185 to 221 °F). If the difference exceeds what is allowed for the programmed time, the P0116 code is stored. It is not a cut wire. It is a sensor that reads wrong, freezes at one value or reacts too slowly, or else a real abnormal condition.

Remember that the code points to the circuit where the computer saw the anomaly, not necessarily the failed part. Check the wiring before you replace the sensor, and test the ECT sensor step by step as described below.

P0116 code symptoms

  • Check engine light on steadily.
  • Radiator fan running continuously.
  • Erratic temperature gauge on vehicles where the dash uses this sensor.
  • Companion codes for the same sensor may appear (low signal, high signal or intermittent).

Likely causes of the P0116 code

  1. Out-of-calibration or degraded sensor that gives a believable but wrong value.
  2. Real abnormal condition: a stuck-open thermostat, a low coolant level or air in the system.
  3. Dirty sensor or one with deposits that make it respond slowly.
  4. High resistance in the connector from corrosion, which shifts the reading.
  5. Computer software. Some manufacturers published updates for false range codes.
  6. Complementary check: a low coolant level leaves the sensor surrounded by air and gives erratic readings, so top off and bleed the system before you diagnose.

How to diagnose the P0116 code step by step

  1. Read the sensor live data and compare it with what is expected. With a cold engine after a full night, the ECT should match the IAT. After starting, the temperature should climb steadily to 85 to 105 °C (185 to 221 °F).
  2. Inspect the connector. Unplug it, look for green, backed-out or oily pins, and plug it back in firmly.
  3. Check the thermostat. If the temperature rises very slowly or never gets past 80 °C (176 °F), the thermostat is stuck open.
  4. With the key on and the sensor unplugged, measure the reference at the connector. There should be about 5 V between the signal and ground.
  5. Jumper test. With the sensor unplugged, the scan tool should show about -40 °C (-40 °F). When you join the two connector pins with a wire, it should jump to more than 120 °C (248 °F). If it does, the wiring is fine and the problem is the sensor.
  6. Measure the sensor resistance and compare it with the technical data table at the current temperature.
  7. Do the wiggle test with the engine running. Move the harness and the connector while you watch the live data, because a jump shows you where the fault is.
  8. Check the continuity of each wire between the sensor connector and the computer connector with the key off.

How to fix the P0116 code

  • Correct the real condition if there is one (thermostat, level, leaks, fuel).
  • If the sensor reads wrong against a reference thermometer or gauge, replace it.
  • Look for technical bulletins or software updates from the manufacturer.
  • Use a quality original or equivalent sensor, because cheap generic ones often have different response curves.
  • Clear the codes, drive one full cycle and check in live data that the reading makes sense.

Technical reference data

  • Approximate resistance: about 2,500 ohms at 20 °C (68 °F) and 200 to 300 ohms at 90 °C (194 °F).
  • Approximate signal voltage: 3 to 3.5 V cold and 0.5 to 1 V with the engine hot.
  • Normal operating temperature: 85 to 105 °C (185 to 221 °F).
  • Open circuit on the scan tool: about -40 °C (-40 °F). Short to ground: more than 130 °C (266 °F).
  • Values are approximate, so check the manufacturer data for your engine.

Brand-specific notes

Many engines have two sensors: one for the computer and one for the dash gauge. A gauge that reads correctly does not rule out an ECT fault, which is worth remembering with any P0116 code.

P0116 on Renault

On some Renault engines the sensor is dual, with two signals in one body.

P0116 on Peugeot

On some Peugeot engines the sensor is dual, with two signals in one body.

P0116 on Volkswagen

On some Volkswagen engines the sensor is dual, with two signals in one body.

Frequently asked questions about P0116

Can I drive with a P0116 code?
With caution and only for a short time. The engine runs on substitute values, so it may lose power or use more fuel and, in some cases, go into limp mode.
Does the P0116 code always mean replacing the ECT sensor?
No. In most cases the fault is in the connector or the wiring. Do the power, ground and continuity tests first.
What is the difference between low signal and high signal?
On a thermistor, a low signal means an impossibly high temperature (a short circuit) and a high signal means an impossibly low temperature (an open circuit).
How much does it cost to fix P0116?
Roughly $15 to $250. The cheapest repair is fixing a connector and the most expensive is replacing the sensor with labor. It varies by shop and region.
What does the P0116 code mean?
It is a generic OBD2 code that means the coolant temperature reading is electrically valid but not believable next to the other sensors. The sensor may read wrong or be stuck, or there may be a real cooling problem.
What is the most common cause of P0116?
A sensor that is out of calibration or reads slowly, or a real condition such as a thermostat stuck open. Check the thermostat and coolant level before you replace the sensor.

Related codes

Questions about the P0116 code

There are no questions about this code yet. Tell us about your case: vehicle, symptoms and what you have already checked.