Technical Description of OBD-II Trouble Code
The vehicle is experiencing a range/performance issue with the Vehicle Speed Sensor “B”. This diagnostic trouble code (DTC) is applicable to OBD-II equipped vehicles such as Honda, Proton, Kia, Dodge, Hyundai, VW, Jeep, and others.
While this code is generic, the specific repair steps may vary depending on the make and model of the vehicle.
What does this mean?
In simple terms, a P2159 trouble code indicates that the vehicle’s speed, as detected by the Vehicle Speed Sensor (VSS) “B”, is outside the expected range (either too high or too low). The VSS input is crucial for the proper functioning of the vehicle systems and is used by the PCM/ECM powertrain/engine control module, along with other inputs.
How does the VSS work?
The VSS is typically an electromagnetic sensor that utilizes a rotating reluctor ring to complete an input circuit to the PCM. It is positioned in the transmission housing in close proximity to the reluctor ring, which is attached to the transmission’s output shaft and rotates along with it.
As the reluctor ring passes by the electromagnetic tip of the VSS, the circuit is rapidly completed and interrupted by notches and grooves. The PCM recognizes these circuit manipulations as transmission output speed or vehicle speed.
A typical VSS or vehicle speed sensor:
Potential Symptoms
This code differs from the P2158 code in that it may not trigger the malfunction indicator light (MIL). The potential symptoms are essentially the same as those associated with the P0500 VSS code:
Causes
A P2159 DTC trouble code may be caused by one or more of the following:
Diagnostic & Repair Steps
As a vehicle owner or DIYer, it is advisable to search for technical service bulletins (TSBs) specific to your vehicle make, model, engine, and year. Following the instructions in a bulletin, if available, can save time and money in diagnosing and repairing the issue.
Next, visually inspect all wiring and connectors associated with the speed sensor. Look closely for any chafing, bare wires, broken wires, melted areas, or other damage. Repair as necessary. The location of the sensor depends on the vehicle and may be on the rear axle, transmission, or wheel hub (brake) assembly.
If the wiring and connectors appear to be in good condition, check the voltage at the speed sensor. The exact procedure will depend on the vehicle’s make and model.
If everything appears to be in order, replace the sensor.
