Camshaft position sensor (CMP)
CMP sensor (crankshaft position) located on the front surface of the left cylinder head. The tip of the sensor passes through the wall and senses the passage of the driving rotor located behind the camshaft pulley. CMP sensor (crankshaft position) is a Hall sensor.
ECM (the engine control unit) uses CMP sensor signal (crankshaft position) , to determine whether the piston in cylinder #1 is at TDC for injection or TDC for exhaust. Based on this, ECM (the engine control unit) actuates the required injector to inject fuel into the cylinder when the piston is at TDC for injection.
CMP sensor (crankshaft position) is a Hall effect sensor and is used by the ECM (the engine control unit) when starting the engine. ECM (the engine control unit) synchronized with CKP sensor signal (crankshaft position) . For this ECM (the engine control unit) based on CMP sensor signal (crankshaft position) performs the identification of cylinder No. 1 in order to select the correct injection timing. When the ECM (the engine control unit) sets injection timing, CMP sensor signal (crankshaft position) no longer used.
To CMP sensor (crankshaft position) 5V power is supplied from the ECM (the engine control unit). Two additional ECM electrical circuits (the engine control unit) provide grounding and signal transmission.
If a malfunction occurs, the ECM (the engine control unit) an error is logged. There are two types of failures: signal frequency too high or no signal at all. Error logged by ECM (the engine control unit), can also refer to a general crankshaft signal failure or dynamic crankshaft signal implausibility. Both possibilities must be checked to determine the cause of the failure.
If a CMP sensor malfunction occurs (crankshaft position) with the engine running, the latter continues to run, but the ECM (the engine control unit) disables boost pressure control. After stopping the engine, restarting it (even though the starter is turning the engine) will not be possible as long as the fault code is in memory.
Crankshaft position sensor (CKP)
CKP sensor (crankshaft position) located at the rear of the cylinder block on the left side. The tip of the sensor is in the plane of rotation of the magnetic disk mounted on the crankshaft. The driving disk is pressed onto the end of the crankshaft. To obtain the correct signal in phase, the driving wheel must be correctly aligned with the crankshaft. At the output of the sensor, a rectangular signal is formed with a frequency proportional to the frequency of rotation of the crankshaft.
ECM (the engine control unit) monitors the CKP sensor signal (crankshaft position) and can register an excess of the permissible engine speed. ECM (the engine control unit) counteracts overspeeding of the engine by gradually nullifying the speed synchronization functions. CKP sensor (crankshaft position) is a Hall sensor. The sensor responds to changes in the magnetic field that occur when the magnetized setting wheel rotates.
The drive wheel is missing two teeth equivalent to 6°of crankshaft rotation. A gap of two missing teeth is used to determine the angular position of the crankshaft.
When the area with the two missing teeth passes near the sensor tip, there is a gap in the signal that the ECM (the engine control unit) is used to determine the position of the crankshaft. The air gap between the sensor tip and the ring is important to ensure that the correct signals are being sent to the ECM (the engine control unit) . Recommended gap between CKP sensor (crankshaft position) and the target is 0.4-1.5 mm.
ECM (the engine control unit) uses CKP sensor signal (crankshaft position) to perform the following functions:
- Synchronization.
- Determination of the moment of the start of fuel supply.
- Fuel pump relay circuit energized (after pre-pumping).
- Formation of the engine crankshaft speed signal, which is distributed via the CAN bus (local area network of controllers) and used by other systems.
Combined mass air flow/intake air temperature sensor (MAF/IAT)
MAF sensor (mass air flow) /IAT (intake air temperature) mounted on the supply air duct directly behind the air filter housing. Two sensors are combined in the sensor housing: MAF sensor (mass air flow) and IAT sensor (intake air temperature) . The sensor is housed in a plastic molded housing that connects the intake manifold and intake manifold.
MAF sensor operation (mass air flow) based on the principle "hot film". There are two film sensitive elements in the printed circuit. The temperature of one element is maintained at the intake air temperature, for example 25°C. The second element heats up 200°C above the intake air temperature, i.e. up to 225°C. Intake air entering the engine passes through the MAF sensor (mass air flow) and has a cooling effect on the film. ECM (the engine control unit) controls the current required to maintain a 200°C difference between the two elements and uses this difference to generate an accurate non-linear signal that matches the amount of air entering the motor.
MAF sensor output (mass air flow) is a digital signal proportional to the mass of incoming air. ECM (the engine control unit) uses this data, along with signals from other sensors and information from stored fuel maps, to determine the exact amount of fuel that should be injected into the cylinders. In addition, the signal is used as a feedback signal for the EGR system (exhaust gas recirculation systems).
In the voltage divider circuit of the IAT sensor (intake air temperature) contains thermistor with NTC (negative temperature coefficient). NTC thermistor (negative temperature coefficient) It works on the principle that the resistance of the sensor decreases as the intake air temperature increases. Since the thermistor allows a higher current to pass to ground, the voltage sensed by the eCm (the engine control unit), decreases. The change in voltage is proportional to the change in intake air temperature. Using the output voltage from the IAT sensor (intake air temperature), ECM (the engine control unit) can correct the fuel delivery table in relation to the intake air temperature. This correction is important because hot air contains less oxygen than cold air of the same volume.
To MAF sensor (mass air flow) supply voltage 12 V from BJB (battery mounting box), with ground connected via the ECM (the engine control unit). Two other circuits connected to the ECM (the engine control unit), are the signal circuits of the MAF sensors (mass air flow) and IAT (intake air temperature).
IAT sensor (intake air temperature) receives 5V reference voltage from ECM (the engine control unit) and shares a common ground circuit with the MAF sensor (mass air flow) . IAT sensor output (intake air temperature) processed by ECM (the engine control unit) by monitoring changes in the reference voltage applied to the voltage divider circuit of the IAT sensor (intake air temperature).
ECM (the engine control unit) checks the calculated air mass against the engine speed. If the calculated air mass value is not plausible, the ECM (the engine control unit) uses a default value of mass air flow, which is formed on the basis of the average engine speed, compared with the characteristics tables stored in the memory. The mass flow value is then corrected for boost pressure, atmospheric pressure and air temperature.
If the MAF sensor (mass air flow) fails, ECM (the engine control unit) implements a default strategy based on engine speed. In the event of a MAF sensor signal failure (mass air flow) any of the following symptoms may be observed:
- Difficult start
- Engine stall after start
- The engine responds sluggishly to the accelerator pedal
- Emission Control System Malfunction
- Malfunction of engine crankshaft speed control in idle mode
- Deterioration of the energy performance of the engine
If the IAT sensor (intake air temperature) fails, ECM (the engine control unit) uses the default intake temperature of -5°C. In the event of an IAT sensor failure (intake air temperature) any of the following symptoms may be observed:
- Increased fuel supply resulting in black smoke from the exhaust pipe
- Malfunction of engine crankshaft speed control in idle mode
Coolant temperature sensor
The engine coolant temperature sensor is located in the upper hose at the outlet of the cooling system manifold. ECT sensor (coolant temperature) sends to the ECM (the engine control unit) and instrument panel for engine coolant temperature information.
ECM (the engine control unit) uses temperature information to implement the following functions:
- Fuel Cycle Calculation
- Engine power limitation due to excessively high coolant temperature
- Cooling Fan Control
- Adjusting the duration of glow plugs
The instrument panel uses temperature information to operate the temperature gauge. The engine coolant temperature signal is also transmitted by the instrument panel via the CAN bus (local area network of controllers) to other systems.
To the ECM sensor circuit (the engine control unit) ECT (coolant temperature) includes an internal voltage divider circuit that includes an NTC thermistor (negative temperature coefficient). As the coolant temperature rises, the resistance of the sensor drops and vice versa. The output signal of the sensor is a change in voltage, which occurs due to an increase in the strength of the current passing through "earth", with temperature change.
ECM (the engine control unit) compares the signal voltage with the values stored in the memory and adjusts the fuel supply, continuously optimizing drivability. Due to fuel condensation on the cold walls of the combustion chamber, the engine requires increased cyclic supply at low coolant temperatures. To enrich the air-fuel mixture ECM (the engine control unit) increases the duration of the opening of the nozzle. As the engine warms up, the mixture becomes leaner.
The sensor input is a 5V reference supplied from the voltage divider circuit in the ECM (the engine control unit). The sensor ground circuit is also connected to the ECM (the engine control unit), which measures the returned current and calculates a sensor resistance value that corresponds to the coolant temperature.
The following table summarizes the coolant temperatures, the corresponding resistance values and voltages.
Characteristics of the coolant temperature sensor
| Temperature, degrees Celsius | Resistance, kOhm | Voltage, V |
| -40 | 925 | 4,54 |
| -30 | 496 | 4,46 |
| -20 | 277 | 4,34 |
| -10 | 160 | 4,15 |
| 0 | 96 | 3,88 |
| 10 | 59 | 3,52 |
| 20 | 37 | 3,09 |
| 30 | 24 | 2,62 |
| 40 | 16 | 2,15 |
| 50 | 11 | 1,72 |
| 60 | 7,5 | 1,34 |
| 70 | 5,6 | 1,04 |
| 80 | 3,8 | 0,79 |
| 90 | 2,9 | 0,64 |
| 100 | 2,08 | 0,49 |
| 110 | 1,56 | 0,38 |
| 120 | 1,19 | 0,29 |
| 130 | 0,918 | 0,22 |
| 140 | 0,673 | 0,17 |
| 150 | 0,563 | 0,14 |
If the ECT sensor (coolant temperature) defective, the following symptoms may be observed:
- Difficulty starting from a cold state.
- Difficulty starting a hot engine.
- Deterioration of engine performance.
- The temperature gauge does not work or works with a large error
In the event of an ECT sensor signal failure (coolant temperature) ECM (the engine control unit) uses the default coolant temperature of 80°C for fuel delivery. In addition, ECM (the engine control unit) constantly drives the cooling fan every time the ignition is turned on, protecting the engine from overheating.
Engine oil temperature sensor
The oil temperature sensor is located in the oil pan. The temperature sensor is an NTC type sensor (negative temperature coefficient). It works in the temperature range from -30 degrees Celsius to +150 degrees Celsius.
Characteristics of the oil temperature sensor
| Temperature, degrees Celsius | Resistance, Ohm |
| 60 | 620 |
| 90 | 255 |
| 120 | 117 |
| 150 | 60 |
Rail fuel temperature sensor
The fuel temperature sensor is located in the return flow line of the left bank of cylinders.
The sensor is an NTC type sensor (negative temperature coefficient) and connected to the ECM (the engine control unit) two wires. To ECM fuel temperature sensor circuit (the engine control unit) includes an internal voltage divider circuit that includes an NTC thermistor (negative temperature coefficient). As the temperature increases, the resistance of the sensor decreases. The output signal of the sensor is a change in voltage, which occurs due to an increase in the strength of the current passing through "earth", with temperature change.
ECM (the engine control unit) continuously monitors fuel temperature. If the fuel temperature exceeds 85°C, the ECM (the engine control unit) puts the strategy into action "performance degradation" engine. The amount of fuel supplied to the injectors is reduced and the fuel is allowed to cool. When switching to this mode, the driver may notice a decrease in power.
Further cooling of the fuel is provided in the heat exchanger, where the fuel, upon reaching a certain temperature, is directed by a bimetallic valve. In vehicles intended for delivery to countries with a hot climate, an electric cooling fan is introduced into the air intake duct of the fuel cooler. The fan is switched on by a bimetallic switch when the fuel reaches a predetermined temperature.
The wires to the fuel sensor are checked by the ECM (the engine control unit) for short circuits and open circuits. ECM (the engine control unit) also monitors the 5 V supply voltage. If a malfunction occurs, information about it is registered in the ECM memory (the engine control unit), and ECM (the engine control unit) uses the default fuel pressure value.
If ECM (the engine control unit) finds that the discrepancy between the pressure sensor signal and the value stored in the memory exceeds the preset value, then in the ECM memory (the engine control unit) a fault code is stored. Depending on the amount of ECM mismatch (the engine control unit) will either limit the cycling, or immediately stop the engine, or will not give permission for the next start.
Stoplight switch
The brake light switch is located on the brake pedal housing and is activated by the brake pedal. The normally open switch closes when the brake pedal is depressed. Switch connected directly to ECM (the engine control unit), while in the ECM (the engine control unit) via CAN bus (local area network of controllers) also receives a brake light signal from the ABS unit (anti-lock brakes).
ECM (the engine control unit) uses the brake-on signal to:
- To limit the fuel supply during braking
- To disable/cancel speed control when brakes are applied
Breaker failure may be accompanied by the following symptoms:
- Speed control system not working
- Increased fuel consumption
Glow plugs
The glow plugs are located in the cylinder heads, on the intake side of each cylinder. Glow plugs and the relay that controls them are essential to ensure the desired starting performance of the engine. When starting a cold engine, the spark plugs heat the air in the combustion chamber, helping to ignite the fuel. The use of glow plugs allows you to reduce the starting fuel supply and, accordingly, reduce the amount of black smoke. In addition, the use of candles makes it possible to reduce the starting angle of the injection advance, which reduces the rigidity of the engine, especially when it is cold, idling.
The operation of glow plugs is divided into three phases:
- Preheat
- Work when scrolling the crankshaft
- post-glow
Preheat is the period of time the spark plugs are on before the starter is turned on. ECM (the engine control unit) adjusts preheat duration based on ECT sensor output (coolant temperature) and battery voltage. If the ECT sensor (coolant temperature) faulty, ECM (the engine control unit) default uses IAT sensor signal (intake air temperature) . The preheating time will be longer if the coolant temperature is low and the battery is partially discharged.
Post-glow is the period of time the candles work after the engine is started. ECM (the engine control unit) adjusts postglow duration based on ECT sensor output (coolant temperature) . Afterglow reduces engine noise ("softens" the working process), improves idling uniformity and reduces hydrocarbon emissions.
When the ignition key is turned to position II, the glow plug indicator light on the instrument panel comes on and the message "PREHEATING" ("PREHEATING"). The glow plug warning light operates independently of the glow plugs, so it does not come on during and after the engine is started. When the control lamp for turning on the glow plugs in these two phases is turned off, the candles themselves can continue to work.
If the glow plugs fail, there is difficulty starting the engine and increased smoke after starting the engine.
The glow plug indicator lamp is also used in the EDC system. If there is a serious malfunction in the EDC system, the glow plug warning light will illuminate continuously and a message will appear on the instrument panel. The driver should have the Land Rover dealer check the engine management system as soon as possible.
Intake air temperature sensor (charge air temperature)
IAT sensor (intake air temperature) located at the rear of the intake plenum directly in front of the electronic throttle. The sensor is used to measure the temperature of the air behind the turbine in order to correct the fuel cycling.
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