GM 12596851 Sensor,Crankshaft Position

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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.

Various engine sensors and components have checking procedures,the engine coolant temperature (ECT) sensor is a thermistor that changes resistance with temperature, and a failure in the circuit can cause trouble codes. The resistance should be measured when cold and warm while ensuring reference voltage from PCM is around 5.0 volts for the verification. Manifold Absolute Pressure (MAP) Sensor monitors changes in intake manifold pressure then varies its voltage output accordingly. Look at the reference voltage and signal voltage with the ignition on and engine off, and observe voltage changes as the engine's vacuum changes. Intake Air Temperature (IAT) Sensor acts as a thermistor where you can measure its resistance at different temperatures to make sure it changes as expected. Also, use a scan tool to monitor the IAT sensor for performance. The oxygen sensor in exhaust detects oxygen content which you can check its millivolt signal while warming up your engine. Check whether the oxygen sensor heater has correct voltage or not. Vehicle Speed Sensor (VSS) provides speed data to PCM which can be checked for reference voltage. Depending on the type of engine, Camshaft Sensor and Crankshaft Sensor should be checked for resistance and proper signal output. Finally, Knock Sensors detect engine knock which should be checked for reference voltage and resistance. If any component fails these checks, replacement may be necessary.

Various engine sensors and components have checking procedures,the engine coolant temperature (ECT) sensor is a thermistor that changes resistance with temperature, and a failure in the circuit can cause trouble codes. The resistance should be measured when cold and warm while ensuring reference voltage from PCM is around 5.0 volts for the verification. Manifold Absolute Pressure (MAP) Sensor monitors changes in intake manifold pressure then varies its voltage output accordingly. Look at the reference voltage and signal voltage with the ignition on and engine off, and observe voltage changes as the engine's vacuum changes. Intake Air Temperature (IAT) Sensor acts as a thermistor where you can measure its resistance at different temperatures to make sure it changes as expected. Also, use a scan tool to monitor the IAT sensor for performance. The oxygen sensor in exhaust detects oxygen content which you can check its millivolt signal while warming up your engine. Check whether the oxygen sensor heater has correct voltage or not. Vehicle Speed Sensor (VSS) provides speed data to PCM which can be checked for reference voltage. Depending on the type of engine, Camshaft Sensor and Crankshaft Sensor should be checked for resistance and proper signal output. Finally, Knock Sensors detect engine knock which should be checked for reference voltage and resistance. If any component fails these checks, replacement may be necessary.

The ignition system will not operate without a crankshaft position sensor input.

If the MIL is illuminated after installation, it may indicate a Diagnostic Trouble Code (OTC) related to the CKP system variation not learned. In this case, a dealer technician can perform the necessary procedure to relearn the variation between the CKP and CMP sensors and clear the OTC from the PCM's memory.

When replacing the CKP sensor, a Crankshaft Position Sensor Variation Learning Procedure should be performed to avoid false diagnostic trouble codes. This involves disconnecting the battery cable, raising and securing the vehicle, removing the skid plate if necessary, disconnecting the electrical connector, removing the mounting bolt, and then installing the new sensor.

The oxygen sensor in the exhaust monitors oxygen content. To check it, you can check its millivolt signal while the engine warms up. It is also important to inspect the oxygen sensor heater and ensure it receives proper voltage.

Loosen the right front wheel lug nuts, raise the vehicle, and remove the wheel and wheel well splash shield.

The engine coolant temperature (ECT) sensor is a thermistor that changes resistance with temperature. To check it, measure the resistance while cold and warm, and ensure the reference voltage from the PCM is around 5.0 volts.

Remove the mounting bolt and discard the old o-ring.