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P0723 is a diagnostic trouble code (DTC) for "Output Speed Sensor Malfunction". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $69.99. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
The P0723 fault code is representative of the condition known as Output Speed Sensor Intermittent. Similar related codes include P0720, P0721, and P0722, which may all indicate a problem with the OSS (output speed sensor) or ISS (input speed sensor).
P0723 is the OBD-II code which indicates an intermittent, erratic, or otherwise abnormal signal produced by the transmission’s output speed sensor (OSS). This sensor sends information to the PCM (powertrain control module), or in some vehicles, to a dedicated TCM (transmission control module) regarding rotational speed of the output shaft. Proper OSS function is crucial because if the signal is faulty, the transmission cannot shift appropriately. While each OSS design varies, in most cases the PCM detects erratic behavior by measuring how long the signal remains at a certain level of RPMs. If this level is maintained at too high of a level for too long, or changes in a way other than expected, the P0723 code will be triggered.
Common causes of this fault code include:
The Check Engine light typically comes on, and there may be perceptible symptoms such as rough or absent shifting, decreased fuel efficiency, speedometer inaccuracy, stalls or hesitation, and/or engine misfires.
As with most repairs, the diagnostic process begins with pulling stored codes and freeze frame data using a specialized scanner. If there are other codes present, these should be addressed in the order they occurred. The codes will then be cleared and the vehicle test driven to see if the code returns.
A technician will visually inspect the wiring and involved components, as well as check the transmission fluid for debris. They will then use a voltmeter to measure the reference voltage and ground signal at the OSS. If one of these circuits is open, the mechanic will then check for continuity and resistance in the circuits.
If everything else is determined to be functioning correctly, your mechanic may use an oscilloscope to live monitor the transmission output speed sensor data. Most often, the output speed sensor itself needs replacing, or there is a bad connection in the circuit.
Due to the complexity of the transmission system, it’s easy to misdiagnose the OSS problem as a transmission or engine malfunction. The VSS (vehicle speed sensor) is also frequently mistakenly replaced in this situation.
This fault code can cause significant drivability problems, which may lead to further damage to the vehicle. It’s crucial to avoid driving as much as you can until you can have the repair made.
Repairing the P0723 code may include the following steps:
There are a number of things to take into consideration when faced with a speed sensor malfunction. The OSS doubles as the VSS (vehicle speed sensor) in some vehicles, so you want to be sure whether you have one or both before attempting repairs. In addition, some vehicles are equipped with a TFT (transmission fluid temperature) sensor, and if this sensor experiences a fault, it can trip an OSS fault code. Due to the wide variety of issues that can cause a P0723, you’re best off consulting a professional mechanic to help with the diagnosis and repair.
YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.