Fault code P011E – engine coolant temperature sensor 1/outside air temperature sensor – correlation

Fault code P011E is called “Engine Coolant Temperature (ECT) Sensor 1/Outside Air Temperature Sensor – Correlation” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.

Technical description and explained code P011E

When the ratio of coolant temperature sensor and ambient air temperature sensor is very different, OBD-II code P011E appears. This occurs when the PCM detects a voltage or resistance value that deviates in either direction from the design parameters.

The temperature sensors on modern engines are of the variable resistance type, which convert temperature into signal voltages. The colder the engine coolant, the higher the resistance. As the coolant temperature increases, the resistance decreases, thereby increasing the signal voltage to the PCM.

It is rare for an engine to have only one coolant temperature sensor. In most cases, one sensor is used to control the thermometer. The other controls the electric radiator fan or the cold start valves in some older systems.

A number of sensor signals are taken into account when performing calculations. Outside air temperature, inside air temperature, air conditioner clutch operation, coolant temperature and others.

If there is a problem with one of the signals, the PCM sets a corresponding diagnostic trouble code (DTC) in memory. If a problem is detected in the outside air temperature or coolant temperature sensor circuit, fault code P011E is set.

To verify the fault, the PCM compares the data received from the Intake Air Temperature (IAT) and Engine Coolant Temperature (ECT) sensors. It also checks the AAT sensor voltage and compares it to the IAT / ECT readings at first cold start.

This code is set if this data is too different. The control module also looks at the voltage signals from these sensors. To determine if they are correct when the engine is fully warmed up.

Symptoms of vehicle malfunctions

The main signal that an error P011E has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.

It can also be warning signs such as:

1. Check engine” control lamp on the control panel will light up (the code will be recorded in the ECM memory as a malfunction).
2. Engine stalls or starts poorly (especially when starting cold).
3. Floating revolutions, as well as attempts to stall at idle.
4. Overheating of the engine.
5. Black smoke coming out of the exhaust pipe, if the mixture is rich.
6. Increased NOx emissions may be observed on a lean mixture.
7. Improper operation of the cooling fans.
8. The outside temperature indicator may malfunction.

Fault P011E is not serious, the car will be able to start and continue driving. But it is better to solve it as soon as possible, because improper heat exchange can lead to more serious consequences.

Factors that can cause this error code

The error code P011E can mean that one or more of the following problems have occurred:

• ECT sensor has failed.
• Faulty ambient air temperature sensor.
• Sensor wiring harness or connectors are damaged.
• Engine coolant level is low.
• Engine coolant thermostat does not open at proper temperature.
• Sometimes the cause is a faulty PCM module.

How to fix or reset OBD-2 code P011E

Some suggested steps for troubleshooting and fix the error code P011E:

1. Read all stored data and error codes with an OBD-II scan tool. To find out when and under what circumstances fault P011E appeared.
2. Clear the error codes from the computer memory and test-drive the vehicle to find out if the error appears again.
3. Check the coolant level (engine should be cold).
4. Visually inspect the electrical wiring and sensor connections for looseness or damage. Repair if necessary.
5. If the ECT or AAT sensor has failed, replace it.
6. Test the thermostat; if it has failed, replace it.
7. Clear the error code from the computer memory again, test drive the vehicle to see if the problem is resolved.
8. If the problem persists, check and reprogram or replace the control module (PCM) if necessary.

Diagnose and repair of problems

The first step in the process of troubleshooting fault P011E, is to review the Technical Service Bulletins (TSB). For known problems with your particular vehicle.

Perform a thorough visual inspection to check the wiring for obvious defects such as scratches, scuffs, exposed wires or burn spots. Next, check connectors and connections for safety, corrosion, and contact damage.

Be sure to carefully check the integrity of the wire harnesses and secure any loose wires. If you find a burned wire, solder it and make sure it is properly insulated.

Check coolant and thermostat

Make sure the coolant level is correct, both in the radiator (when cold) and in the coolant overflow tank. Make sure that there are no leaks and that the sealed cap is working properly.

If there is not enough coolant in the system, the engine may not warm up properly. Because if the temperature sensor is not in contact with the coolant, it will not read the temperature.

Using a non-contact thermometer, or a real-time streaming scan tool, check to see if the engine is warming up properly. Normally, the upper radiator hose should stay relatively cold until the thermostat opens. After that, it will warm up quickly.

If the thermostat is open, the coolant will leak constantly, preventing the engine from reaching operating temperature. This can also be the cause of the P011E trouble code.

Use a thermometer or diagnostic tool to check the engine temperature after 10-15 minutes of operation. If the temperature does not reach the operating temperature, check the ECT sensor.

Check the coolant temperature sensor (ECT)

Visually check the sensor for wiring or connector damage and repair if necessary. Then connect the OBD2 scanner, if the engine temperature is excessively high, about 140°C, this is not normal.

Disconnect the sensor on the engine and see if the reading drops by, say, 10°C. If it does, the sensor is probably faulty, shorted internally, causing a low resistance signal to be sent to the PCM.

But, if you want to be completely sure it’s the sensor and not the wiring, you can do a test. Check the resistance of the sensor against ground with an ohmmeter. The resistance of a normal sensor will vary slightly from car to car.

But basically, if the engine temperature is around 95 degrees Celsius, the resistance will be around 200 ohms. At about -20 degrees Celsius, the resistance will be over 10,000 ohms.

You can use this test to determine if the resistance of the sensor matches your engine temperature. If it doesn’t match your engine temperature, you probably have a faulty sensor.

Checking the Outside Temperature Sensor and Electrical Circuits

If the P011E code returns after a visual inspection and correction, you will need to test the AAT sensor and its associated circuits. Normally there are 2 wires to the AAT sensor.

With the ignition off, disconnect the wiring harness from the AAT sensor. Turn on the ignition and use a diagnostic tool to read the AAT sensor voltage. The voltage should be about 5 volts.

Then turn off the ignition, connect a jumper to the two terminals inside the AAT harness connector, and then turn on the ignition. The reading should be about 0 volts.

If there is no 5 volts on the sensor or you see no change, the wiring from the PCM to the sensor is most likely faulty, or the PCM itself is faulty.

When all the tests are successful, but fault P011E remains, most likely the cause is a faulty AAT sensor. Although a faulty control module cannot be ruled out until the AAT sensor is replaced.

On which vehicles does this problem occur most frequently

Fault code P011E can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:

• Audi
• Skoda
• Volkswagen

Fault code P011E can sometimes be found with other errors. The most common are the following: P008F, P00B6, P0115, P011A, P011B, P011F, P2182.

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