99 astro van signs of bad ecu diagnostic port
If you notice that your cruise control does not engage when you press the button, contact a mechanic so they can inspect the vehicle and determine why the cruise control is not working. As a safety precaution, the ECU will shut down the cruise control and render it inactive.
#99 ASTRO VAN SIGNS OF BAD ECU DIAGNOSTIC PORT CODE#
When the sensors fail to deliver accurate data to the onboard computer on your car, truck, or SUV, the powertrain control module (PCM) will send an error code to the vehicle’s ECU. Since the transmission speed sensors monitor the input and output shaft speed, it also plays a part in monitoring the cruise control. If you notice your transmission is shifting harshly or roughly, you should contact a local ASE certified mechanic as soon as possible. When the transmission shifts hard, it can damage internal components including valve bodies, hydraulic lines, and in some cases mechanical gears. An automatic transmission is hydraulically controlled and designed to shift smoothly. It's also common that a problem with these sensors can impact the shift timing, extending the interval between transmission shifts. This may cause the transmission to shift roughly or more quickly than normal. Without a valid speed signal from these sensors, the PCM will not be able to correctly control the shifting of gears within the transmission. Should either or both of these speed sensors fail, you may notice one or more of the following 3 issues: 1. If the desired gear and the actual gear do not match, then the PCM will set a diagnostic trouble code (DTC) and illuminate the Check Engine Light. The actual gear ratio is then compared to the desired gear ratio.
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If either of these two sensors falls out of alignment or experiences electrical issues, it impacts the operation of the entire transmission.Īfter registering data, the two transmission speed sensors, also commonly referred to as a vehicle speed sensors (VSS), send data to the powertrain control module (PCM), which compares these two inputs and calculates which gear the transmission should engage for efficient driving.
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The other sensor is the output shaft speed (OSS) sensor. As described, this sensor is used to monitor the speed of the transmission’s input shaft. The first is known as the input shaft speed (ISS) sensor. There are generally two speed sensors that work in conjunction to provide accurate transmission data to the vehicle’s powertrain control module. The transmission speed sensors are used to calculate the actual gear ratio of the transmission while in use.