What is OBD-II Code P28E9 – Shift Motor Position Sensor Circuit Low
As a mechanic, I often see customers come to me with a check engine light on their dashboard. In most cases, when I connect the OBD-II scanner to their vehicle, the code displayed reads P28E9. This code indicates that there may be a malfunction in the shift motor position sensor circuit, which is responsible for sensing the position of the shift motor that controls the shifting of the gears in automatic transmissions.
In this article, I will explain what OBD-II Code P28E9 means, what may have caused it, how to diagnose the issue, and the options for fixing the problem.
What is OBD-II Code P28E9?
The P28E9 code is related to the shift motor position sensor circuit in the transmission system of an automatic vehicle. The shift motor is responsible for moving and shifting the gears within the transmission system, and the position sensor circuit is responsible for determining the exact position of the shift motor.
When this code is triggered, it usually indicates that there is an issue with the sensor circuit. Specifically, it may refer to a low voltage in the electrical circuit that is connected to the shift motor position sensor. This voltage indicates that there may be an issue with the wires or connections within the circuit, or the sensor itself may be malfunctioning.
What may have caused OBD-II Code P28E9 to be triggered?
There are several potential causes for this code to be triggered in a vehicle. Some of the most common causes include:
1. Damaged or Faulty Wiring: Issues with the wires that connect the shift motor position sensor to the transmission control module (TCM) may cause P28E9 to show up. Damaged wires or connections may produce a decrease in the voltage that the TCM receives, causing the code to be triggered.
2. Burned Out Shift Motor Position Sensor: With prolonged use, the shift motor position sensor may burn out or become faulty. When this happens, the TCM may receive low voltage signals from the sensor. This may trigger the P28E9 code.
3. Problems with TCM: In some cases, P28E9 may be due to other problems within the TCM, which includes malfunctioning software or other issues affecting the transmission system.
How to diagnose P28E9 Code
When experiencing the P28E9 code, the following steps can be taken to diagnose the issue:
1. Begin by connecting an OBD-II scanner to the vehicle to read the code and determine the exact problem.
2. Inspect the wires and connections that make up the sensor circuit for any signs of damage or wear. Ensure that they are firmly in place.
3. Use a multimeter to check the voltage level of the sensor circuit. If the voltage is low, it indicates that there may be an issue with the sensor circuit or other components within the transmission system that needs to be fixed.
4. Disconnect the shift motor position sensor and test it using an ohmmeter. If there is a problem with this part, the continuity level will indicate that it is faulty, and it needs to be replaced.
5. Finally, if none of the above diagnostics work out, the issue may be within the TCM, and a more in-depth diagnosis may be required.
How to repair P28E9 Code
Fortunately, once the issue has been diagnosed, there are options for fixing the P28E9 code. These include:
1. Fixing the Wiring: If the issue is with the wiring, repairing or replacing the damaged wires and connections should solve the problem.
2. Replacing the Shift Motor Position Sensor: If the sensor is burnt out or malfunctioning, it can be replaced with a new one.
3. Repairing or Replacing TCM: When the problem is related to the TCM, a mechanic can reprogram or replace it to resolve the issue.
Frequently Asked Questions:
1. What is the cost of fixing P28E9 code?
The cost of fixing P28E9 code depends on the severity and type of problem encountered. The cost of repairing the circuit, replacing the sensor, or reprogramming/replacing the TCM can vary, and it is advised to consult your mechanic for an estimate.
2. Can P28E9 code cause harm to my vehicle?
P28E9 code may cause transmission problems and should be addressed promptly to avoid risking significant damage to your vehicle.
3. Can I continue to drive my car with P28E9 code?
If the P28E9 code appears, it is advisable to get your vehicle inspected by a mechanic as soon as possible. It is not recommended to continue driving your car until the issue has been resolved completely.
4. How long will it take to fix P28E9 code?
The time required to fix P28E9 code depends on the severity of the issue, the parts to be replaced, and the type of repair. However, most repairs take between one to two hours, with more complicated problems taking longer.
5. Can I diagnose P28E9 code by myself?
While the OBD-II scanner can be used to diagnose P28E9 code, it is advised to take your vehicle to a mechanic for a proper diagnosis and repair.
Conclusion
The P28E9 code is related to the shift motor position sensor circuit in the transmission system, indicating a malfunction with the sensor or circuit. By diagnosing the issue and repairing the circuit, replacing the sensor, or reprogramming/replacing the TCM, the P28E9 issue can be resolved. It is essential to address this issue promptly to avoid further damage to your vehicle.