Oldsmobile 10238816 Switch,Idle Speed Control P/S Pressure

While making checks, do so using a high-impedance, 10-megohm digital multimeter, to avoid destroying the PCM. On models featuring an anti theft audio system, turn off the anti theft system prior to disconnecting the battery or interrupting the battery supply to the stereo. In certain cases, after the Check Procedure, a trouble code is set, so, to erase all the codes in the PCM, remove the PCM-B fuse or disconnect the cable from the negative terminal on the battery for thirty seconds. In some instances, it might be relevant to employ pins or straightened paperclips to backprobe on the sensor electrical connector cables; always turning special attention not to short the probes. The A/C compressor clutch is managed by the PCM; the clutch will not engage until the engine idle speed is raised due to the load applied. Verify that your battery voltage at the a/c clutch with ign on, a/c on; if there is no battery voltage then check the fusable link and wires for damage. In the event you find that the fuse is all right, you should attempt to find voltage to the A/C compressor clutch relay. The camshaft position sensor under the distributor cap relays cylinder identification to the PCM and is not part of the ignition system. Check to see if the sensor is getting battery voltage at the harness connector if not check the fuses and if wires are the issue. The crankshaft position sensor uses the change in the magnetic field every time the reluctor ring passes, and sends pulses to the PCM to assist in ignition timing and the control of fuel injection. The ECT sensor which is also a thermistor changes its resistance to the flow of current with temperature and thus alters the voltage output which is fed to the PCM. Check whether the ECT is getting reference voltage and check the resistance of the ECT at cold as well as at normal operating condition. The IAC valve regulates the low speeds of the engine to control the driving of automobile whereas the IAT is a sensor whose function is to measure the temperature of intake air which it alters the voltage signal to the PCM. Knock sensor rules an engine knock, as the PCM states that the ignition timing be changed. The MAP sensor monitors the change in pressure inside the intake manifold and translates the same into voltage for the purpose of fuelling and controlling ignition timing. The MAF sensor relates to the airflow quantity entering the engine and the oxygen sensor measures the exhaust gas oxygen content. The Park/Neutral switch does not allow the engine to start unless the gear is in Park or Neutral and the power steering pressure switch raises idle rate under load. The TPS is installed on the throttle body and is responsible for monitoring the position of throttle valve in order to supply fuel and the VSS provides pulsing voltage signal to the PCM to be converted to mph.

When testing, only use a high-impedance (10 mega ohms) digital multi-meter to avoid shorting / shocking the PCM out. On models that are fitted with a Theftlock audio system, verify that the lock out feature is switched off before removing the battery terminal. The self-diagnosis system can only be activated by the TECH 1 SCAN tool - if that is not available, obtain the vehicle codes from a dealer or an authorized repair center. Thermistors that are resistors with varying resistance according to the temperature ought to be high when the temperature is low, and low as the temperature increases. To verify, turn on the multi-meter by selecting the ohms range, remove the harness connector and then place the test probe of the multi-meter on both terminals of the sensor. After checking resistance, check for reference voltage from computer it should be 5.0 volts with ignition switch on. Electrical rotary devices such as the throttle position signal should be tested by back probing the harness connector and noting voltage changes when the signal arm is varied. Intake manifold pressure/vacuum sensor monitors the pressure variation at the intake manifold and should display voltage from below 2.0V when the engine is idle to above 4.0V WOT. Magnetic reluctance sensors including crankshaft and vehicles speed sensors include observing fluctuation of voltage by using AC volt meter when the engine is cranking or by rotating the sensor. Hall effect sensors output ON/OFF signals to the powertrain control module, and should display voltages when the engine is turned over. Dual Hall effect sensors work in the same manner, but they give two different ON/OFF signals. Oxygen sensors measure exhaust gas oxygen content with a voltage signal range of 0.1-0.9 Volts: test for millivolt signals as the engine warms. MAF sensor, records the air getting into the engine and its readout is in grams per second by use of a SCAN tool. Engine vibration is sensed by knock sensors and they generate ac output voltage which should vary when tapped. The NVLD switch lights up when the transaxle is in Park/Neutral taping various systems. The PCM acts on the acoustic knock sensors to alter engine load and the air conditioning compressor clutch for the same as well as the power steering pressure sensor to observe fluid pressure that may cause idle problems. The fuel tank pressure sensor is used during emissions checking of the pressure while the Torque Converter Clutch system in automatic transaxles operates to lock the torque converter at cruising speed while allowing minor adjustments to fuel saving; it requires tools that are special to check and repair.

Unscrew the cable bolt and remove the cable.

Detach the retaining bolt and unplug the sensor.