TPS sensor DTC problems
Among other parameters from the TPS sensor that ECU uses in the calculations of the air-fuel ratio and ignition timing, one of the most obvious problems related to this sensor is hesitation during the rapid acceleration. Wrong or undue signal in the form of changes in output voltage from the sensor may be the cause of this problem and others related to engine performance and fuel consumption.
Checks and measurements of this sensor can be also performed with the voltmeter (depending of the type of sensor). Knowing that these sensors usually work as sliding resistors, it will not be difficult to conclude that the output voltage is proportionally falling when opening or closing the throttle. Of course, it is necessary to check the sensor power supply on positive terminal of the sensor connector.
Checks and measurements of this sensor can be also performed with the voltmeter (depending of the type of sensor). Knowing that these sensors usually work as sliding resistors, it will not be difficult to conclude that the output voltage is proportionally falling when opening or closing the throttle. Of course, it is necessary to check the sensor power supply on positive terminal of the sensor connector.
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As these sensors are mostly mechanical sliding resistors, the problem is mainly associated with oxidation of the sliding elements or worn bushes causing free-play in the sensor and poor contact. It often happens that measuring of output voltage is correct, but after running car for several kilometres MILL turns back on with the same DTC.
Therefore, when measuring the output voltage from the sensor, use a plastic screwdriver handle and gently tap on the sensor. If there is a poor contact on electrical sliders inside the sensor, we will not have continuous but interrupted output voltage. If this is the case, we can conclude that sensor is defective. Such a sensor can be replaced, but those more experienced can try to dismantle the sensor, clean the con- tacts and test it again.
Therefore, when measuring the output voltage from the sensor, use a plastic screwdriver handle and gently tap on the sensor. If there is a poor contact on electrical sliders inside the sensor, we will not have continuous but interrupted output voltage. If this is the case, we can conclude that sensor is defective. Such a sensor can be replaced, but those more experienced can try to dismantle the sensor, clean the con- tacts and test it again.
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Certainly, such task can be performed on older vehicles models, while newer cars have mostly sealed elements which can not be repaired. On new types of cars, TPS sensor is automatically calibrated by the installed program in the ECU. On older types of cars, it is necessary to calibrate the TPS. Calibration possibilities we shall find only in more complex programs provided for the diagnosis of specific types of vehicles.
In the photographs we see the usual TPS sensor position on the throttle shaft, and disassembled sensor with sliding contacts. Going back to the sensor test, it should be noted that skilled mechanics will cope with sensor terminals and measurement values. The others will look for specifications in workshop manuals or in data programs.
On the following sketches we see shown examples of connecting and calibrating the TPS sensor in the program for a particular type of vehicle. TPS sensors usually have only three terminals.
On the sketch, the positive terminal or sensor power supply, whose value is usually 5V, is highlighted in yellow. The negative terminal or earth is highlighted in black, while the sensor output terminal whose voltage value varies from 0-5V is highlighted in green. On the program window we see the option Basic Settings.
In the photographs we see the usual TPS sensor position on the throttle shaft, and disassembled sensor with sliding contacts. Going back to the sensor test, it should be noted that skilled mechanics will cope with sensor terminals and measurement values. The others will look for specifications in workshop manuals or in data programs.
On the following sketches we see shown examples of connecting and calibrating the TPS sensor in the program for a particular type of vehicle. TPS sensors usually have only three terminals.
On the sketch, the positive terminal or sensor power supply, whose value is usually 5V, is highlighted in yellow. The negative terminal or earth is highlighted in black, while the sensor output terminal whose voltage value varies from 0-5V is highlighted in green. On the program window we see the option Basic Settings.
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The menu shows the values of the TPS sensor (TPS Settings) in the highest (High) and lowest (Low) throttle opening position, which we obtained by clicking on the Fetch From ECU. If the program does not provide automatic values adjustment for particular type of engine,
we can enter them manually, previously finding them in workshop manuals or else where. After entering appropriate values and clicking on the Send to the ECU, we have completed the sensor calibration.
we can enter them manually, previously finding them in workshop manuals or else where. After entering appropriate values and clicking on the Send to the ECU, we have completed the sensor calibration.