Error p0118 stands for “coolant temperature sensor - high signal level.” It occurs if the electronic engine control unit (hereinafter referred to as the ECU) detects that a voltage above the threshold is supplied from the specified sensor, that is, above 4.91 Volts. Most often, the cause of error p0118 is an open circuit of the sensor or failure of the sensor itself. Eliminating the error code and the problem itself in general consists of one of the following options - replacing the wires of the sensor circuit, replacing the sensor connector, replacing the sensor itself with a new one.
What are the symptoms of a P0118 code?
- When this error appears, the Check Engine light will light up on the vehicle's dashboard. The ECM will put the engine into limp mode, replacing the incorrect coolant temperature sensor reading with a value of 80°C (176°F).
- The car engine may be difficult to start when cold. When warm, the engine starts normally.
- The car engine may run rough until it warms up.
- After warming up, the engine usually runs normally.
Note : Symptoms of this error may vary depending on the make and model of your vehicle.
Symptoms of malfunction
The main driver symptom of P0118 is the MIL (Malfunction Indicator Light). It is also called Check engine or simply “check light”.
They can also appear as:
- The “Check engine” warning light on the control panel will light up (the code will be stored in the ECM memory as a malfunction).
- The engine stalls or has difficulty starting (especially when starting from cold).
- Floating speed, as well as attempts to stall at idle.
- Car engine overheating.
- Black smoke from the exhaust pipe when running on a rich mixture.
- On a lean mixture, increased NOx emissions may occur.
- Incorrect operation of cooling fans.
Error P0118 is not serious, the car will be able to start and continue driving. But it is better to solve it as soon as possible, since improper heat transfer can lead to more serious consequences.
How does a mechanic diagnose a P0118 code?
When diagnosing this error, the mechanic will do the following:
- Visually inspect the coolant temperature sensor and related electrical wires and connector
- Reads all stored data and error codes using an OBD-II scanner to find out when and under what circumstances the P0118 error occurred
- Clear the error codes from the computer's memory and test drive the vehicle to see if the P0118 code appears again
- Check the electrical wires and coolant temperature sensor connector for corrosion and damage.
- Observes the coolant temperature sensor readings in real time using a scanner
- If necessary, replace the coolant temperature sensor, associated electrical wires and connector, or engine control module (ECM)
Diagnosis and problem solving
The first step in the process of troubleshooting P0118 is to review the Technical Service Bulletins (TSBs). For known problems with a specific vehicle.
Perform a thorough visual inspection to check the wiring for obvious defects such as scratches, scuffs, exposed wires, or burn marks. Next, you should check the connectors and connections for safety, corrosion and damage to the contacts.
Be sure to carefully check the integrity of the wire harnesses and secure any loose wires. If you find a burnt wire, solder it and make sure it is properly insulated.
Checking the coolant and thermostat
Make sure the coolant level is correct, both in the radiator (when cold) and in the coolant overflow reservoir. Make sure there are no leaks and that the sealing 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 scan tool with real-time data streaming, check to see if the engine is warming up properly. Typically, the upper radiator hose should remain relatively cool until the thermostat opens. After which it will heat up quickly.
If the thermostat is open, coolant will flow continuously, preventing the engine from reaching operating temperature. This may also be the reason for the P0118 trouble code.
Using a thermometer or scan tool, check the engine temperature after 10-15 minutes of operation. If the temperature does not reach operating temperature, check the ECT sensor.
Checking the coolant temperature sensor (ECT)
Visually check the sensor for damage to the wiring or connector and repair if necessary. Then connect the OBD2 scanner, if the engine temperature is excessively high, about 140°C, it is not normal.
Disconnect the sensor on the engine and see if the readings drop by, for example, 10°C. If so, then the sensor is most likely faulty, shorted internally, causing a low resistance signal to be sent to the PCM.
But, if you want to be completely sure that it is the sensor and not the wiring, you can run a test. Check the sensor's resistance to ground using an ohmmeter. The resistance of a normal sensor will vary slightly depending on the vehicle.
But basically, if the motor temperature is around 95 degrees Celsius, then the resistance will be around 200 ohms. At a temperature of about -20°C, the resistance will be more than 10,000 Ohms.
This test will help you determine if the sensor resistance matches the engine temperature. If it doesn't match your engine temperature, then you probably have a bad sensor.
How serious is P0118?
When P0118 occurs, the vehicle's ECM will put the engine into limp mode. Staying in limp mode may result in unstable engine operation, which will continue until the engine warms up to normal operating temperature. Possible increased fuel consumption and excessive carbon buildup on engine components. Driving a vehicle in limp mode for long periods of time can lead to a number of other problems, including problems with the ignition system. Also, the cooling system fans can run continuously.
On which cars is this problem most common?
The problem with code P0118 can occur on different machines, but there are always statistics on which brands this error occurs more often. Here is a list of some of them:
- Audi (Audi a4, Audi a6, Audi TT)
- BMW
- Chery
- Chevrolet (Chevrolet Aveo, Camaro, Cruz, Lacetti, Malibu, Silverado)
- Chrysler (Chrysler Voyager, Town Country, 200)
- Citroen (Citroen C3, C4)
- Daewoo (Daewoo Nexia)
- Dodge (Dodge Caravan)
- Ford (Ford Transit, Focus, Fusion, Explorer)
- Honda (Honda Accord, Odyssey, SRV, Stream, Fit, Civic)
- Hyundai (Hyundai Accent, Santa Fe, Solaris)
- Jeep (Jeep Grand Cherokee)
- Kia (Kia Rio)
- Lexus
- Mazda (Mazda 3, Mazda 6)
- Mercedes
- Mini (Mini Cooper)
- Mitsubishi
- Nissan (Nissan Almera, Altima, Qashqai, Murano, Note, Patrol, Primera)
- Opel (Opel Astra, Corsa)
- Peugeot (Peugeot 206, 308, Partner)
- Pontiac (Pontiac Grand AM)
- Renault
- Saturn (Saturn SC)
- Skoda (Skoda Octavia, Fabia)
- Subaru (Subaru Tribeca, Forester)
- Suzuki
- Toyota
- Volkswagen (Volkswagen Golf, Passat, Touareg, Transporter)
- Volvo
- VAZ 2105, 2107, 2110, 2112, 2114, 2115
- Volga Chrysler
- Gazelle Business, Chrysler, Sobol, ZMZ 405, UMZ 4216
- Lada Granta, Kalina, Niva, Priora
- UAZ
With fault code P0118, you can sometimes encounter other errors. The most common ones are: P0108, P0113, P0119, P0123, P0138, P0301, P0340, P0351, P0453, P0507, P0708, P1400, P1406, P1557, P2305.
Where is the sensor located
The location of the described unit is the engine compartment near the cylinder head (on the exhaust pipe), the thermostat. This is a standard location, for example, like the VAZ 2114. Appearance - plastic, rectangular box, plug with a metal part with a thread and a contact segment. There are 2, less often 3, wires going to the device.
VAZ fault code P0118 check.
This can be done if you have a multimeter, on-board computer or a device for reading fault codes. Before starting the test, it is necessary to check the reliability of the connection of the plug to the sensor and the integrity of the wires.
To check, you need to disconnect the contact block from the sensor, turn on the ignition, and check for the presence of fault code PO117: low signal level of the coolant temperature sensor. The appearance of this code indicates that the circuit and controller are working properly and the sensor needs to be replaced.
If the code does not appear, it means that wire 17 O is shorted to ground or to wires 7 Z and 53 ZP, connecting the sensor to pin 26 of the controller. The controller may also be faulty.
If there is no diagnostic tool available to read error codes from the controller’s RAM, and the car is not equipped with an on-board computer, it is necessary to check the serviceability of the sensor. To do this, we heat it, any heated container with water is suitable for this, and check the resistance between its terminals. The resistance must correspond to the temperature indicated in the table. It is enough to check the readings corresponding to a cold and warm engine. If the temperature and resistance do not match, the sensor is replaced with a working one.
If the fault code is not permanent, that is, it disappears periodically, it is necessary to check the reliability of the sensor connector connection and check the sensor ground circuit, wires 7 Z and 53 ZP.
Source
What does code P0118 mean?
Modern cars have an electronic monitoring system (ECM) of the state of the internal combustion engine with a control unit (ECU). By connecting a diagnostic scanner-adapter to the unit, you can find out about the operation of the motor. Data is displayed in brief alphanumeric notifications. These codes include P0118, which indicates that excessive voltage has been detected on the coolant temperature sensor (CTS) circuit. Appears when 4.91 V is exceeded.
So, if the output voltage of the coolant sensor (detector, detector) that monitors the temperature level of antifreeze exceeds 4.91 V, then the ECM registers a problem in its circuit and signals this with code P0118, which can be seen on the display of the diagnostic adapter connected to the ECU.
Explanation of the described error: “high signal level”. The coolant sensor is a thermistor; a 5 V power supply is supplied to it from the ECU. The detector returns a voltage that decreases as t° increases. In this way, monitoring and feedback from the system occurs. Code P0118 shows that the internal combustion engine control unit detects an excessively high incoming voltage from the device, the normal level of which is 1.5 - 2 V. For most vehicles, the threshold is 4.91 V. The ECU forcibly deactivates the sensor, following its programmed algorithm, and makes a switch to emergency condition. Plus, the impellers of the cooling system can be activated; they are constantly running on the radiator.
How to carry out repairs
If OBD P0118 is detected in the ECU memory, do the following:
- The ignition is activated, but the engine does not start.
- A diagnostic vehicle error scanner is connected to the ECU (to its connector), and it also receives data on the parameters of the entire system. Select “t° cooling” in the menu. liquid."
- If the temperature of the antifreeze on the instruments is below +135°, then if there are no other errors in the control unit’s memory, check the grounding of the sensor (integrity of wiring, contacts). The electrical circuit diagram is in the technical documentation of the vehicle and the device. At the same time, check all connections.
- Snap off the block (chip) with the conductors. If the device continues to show above +42°, then its signal wire is shorted to ground or the ECU is broken. If it is lower, then there is a problem in the sensor itself, in which case there is only one way out - replacement (but after preliminary additional testing).
The coolant sensor is in direct contact with the cooler, so if there are signs of overheating, it should not be removed.
Re: M9R won't start
The chain slipped on the car, after repairing and replacing 3 injectors (we managed to get one intact), the car started up, ran for about 5 minutes, turned it off, assembled the attachment and did not start again. Then I prescribed the injectors (Delphi scanner) I thought it might help, but it didn’t help. When diagnosing an error in the camshaft sensor DF119, I removed the timing cover and installed the camshaft and crankshaft lock, that is, the phases are not shifted. Starts on air. One specialist said that it should start if you disconnect the chip from the camshaft sensor, but no. Then I took out one injector and when I cranked the starter there was no injection!
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