Toyota car repair skills If you encounter in the maintenance of Toyota models: intake manifold absolute pressure sensor signal instability, oxygen sensor flange gasket leakage, transmission shaft slip joint adhesion and other issues, this article will provide you with a rare Maintenance skills.
    We are going to discuss the issue of: intake manifold absolute pressure sensor test questions, how to find oxygen sensor leaks and correct the drive system for shaking and vibration problems.
    MAP sensor test method
    Not all Toyota models use impeller air flowmeters. For example, most corolla (Corolla) and four-cylinder Camry (Camry) cars are used flow velocity - density intake system (according to the intake pipe pressure measurement engine intake), MAP (intake manifold absolute pressure sensor) The most important sensor in the gas system. Like other velocity-density air intake systems, the damaged Toyota MAP can cause malfunctions such as engine speed mutations (jitter), surge, stall, or full-speed operation.
    MAP failure for a variety of reasons, the reason why the diagnosis is more difficult, for several reasons:
    First and foremost is the difference between the flow rate and the density intake system on the domestic car, because the failure rate of the MAP is very low, so many maintenance personnel do not put it in the list of the main suspects of the fault.
    Second, in the thousands of already installed OBD-II Toyota car, when the MAP fails, there will be no corresponding fault code output. Even worse, many maintenance personnel are not familiar with the Toyota car MAP unique test mode. The correct test method enables the PCM (power control module) to capture the intermittent MAP fault signal. If you see the TE2 terminal in the diagnostic socket, you will know that the system also has this test function.
    Third, incorrect test steps or imperfect test methods can prevent the diagnosis of MAP faults. Before the test, it is necessary to ensure that the pressure gauge on the vacuum pressure gauge and the hand-held vacuum pump is accurate. It is not difficult to find a pressure gauge that is relatively easy to use in the 1-2in./Hg (inches of mercury, pressure units, 1 inch of mercury equivalent to 0.035Pa). When there is doubt about the accuracy of the table, Adjustment or professional calibration.
    In addition, only after you verify the MAP obtained by the intake pipe vacuum signal reliability, can continue to proceed. The test method is: the vacuum pressure gauge into the MAP hose, the engine heat engine when a few feet throttle. If the pressure gauge is as normal as possible without any reaction, connect it to a vacuum pump with good working conditions to re-do the above test. If the boom oil inspection is normal, then you follow the MAP hose up to the tube to the terminal, to see what is a problem.
    If the sensor is receiving an accurate vacuum signal, then it is sure that it is getting a 5V reference voltage from the PCM and is well grounded. Then, for all Toyota MAP sensors, you can test the following steps: Turn on the ignition switch, turn off the engine so that the MAP signal voltage is at 3.60 ± 0.25V. After that, connect the vacuum pump to the sensor. The MAP signal voltage drops by 0.10V for every 1in./Hg pressure on the sensor. That is, if the sensor with 10in./Hg pressure, MAP signal will drop 1V.

    Finally, the response curve of the sensor is detected by a digital oscilloscope, and the graph of the left side of the throttle position sensor signal is a normal response curve of a typical MAP sensor similar to that of a MAP sensor. Although the curve comes from a generic MAP sensor, but only with the Toyota sensor is the voltage range.