In older vehicles, a faulty transmission speed sensor seems to only affect the speedometer. However, driving a vehicle with a broken speedometer is illegal in most states within the United States. In modern vehicles, the anti-lock brakes and traction control are disabled once the speed sensor fails.
Can a speed sensor cause a transmission not to shift?
Without a valid speed signal from these sensors, the PCM will not be able to correctly control the shifting of gears within the transmission. This may cause the transmission to shift roughly or more quickly than normal.
What are the symptoms of a bad transmission speed sensor?
5 Common Bad Speed Sensor Symptoms
How does the speed sensor affect the transmission?
A transmission speed sensor calculates the transmission gear ratio when in use. A car has two speed sensors: the ISS and the OSS, working together to show the transmission data to the car's powertrain module. If these sensors get misaligned, the operation of the transmission system will be affected.
Related Question Can speedometer affect transmission?
Can a bad instrument cluster cause transmission problems?
It depends on where a vehicle's gearbox gets its road speed signal. When an instrument cluster fails in this situation, the gearbox may receive incorrect vehicle speed data that could result in premature or delayed gear change timing that could play with the transmission.
What tells transmission to shift?
When your vehicle's computer tells the transmission to shift gears, hydraulic pressure (provided by the fluid) squeezes a series of plates together inside a clutch pack to connect the engine to the transmission output shaft and route power to the wheels.
What can a bad knock sensor cause?
A bad knock sensor may also not let the engine accelerate properly while driving on the highway, and cause the vehicle to lose fuel mileage. Once the computer realizes the knock sensor is not working properly, your vehicle will most likely lose power.
Does the ECM control the speedometer?
The ECM on this vehicle needs to know what the vehicle speed is so that it can manage spark and fuel outputs as well as the cruise control function on this throttle by the wire equipped engine. So you can have a transmission that shifts correctly, a speedometer that works yet and not read any VSS signal on the scanner.
How much does it cost to fix my speedometer?
If you're doing this with a mechanic, they will usually charge you around $100 to $250. Issues with your sensors or your actual speedometer do not cost much but, if the issue lies deeper and requires additional diagnostics, you can expect to pay between $200 and $400.
How long does it take to replace a transmission range sensor?
How long does it take to replace a transmission sensor? It can take a bit longer depending on the level of damage. Some professional technicians complete the entire replacement task in two or three hours.