P0900 Clutch Actuator Circuit/Open
OBD-II Trouble Code Technical Description
Clutch Actuator Circuit/Open
What does that mean?
This is a generic powertrain diagnostic trouble code (DTC) and applies to many OBD-II vehicles (1996-newer). That may include but is not limited to vehicles from Toyota, Smart, Ford, Mazda, Hyundai, Mercedes, etc. Although generic, the exact repair steps may vary depending on year, make, model and powertrain configuration.
OBD-II trouble code P0900 and related codes P0901, P0902, and P0903 are associated with the clutch actuator circuit. This circuit is monitored by the Engine Control Module (ECM), the Power Control Module (PCM) or the Transmission Control Module (TCM) based on the specific vehicle.
The purpose of the clutch actuator circuit is to engage and disengage the clutch or clutches on a semi-automatic transmission. Based on the specific vehicle and the configuration, several sensors and associated components are required to accomplish this task. Some configurations incorporate two hydraulic clutches, one for even gears and another for odd gears. The number of gears may range from 6 to 9 on newer vehicles. Basically, this design facilitates gear changes that are smooth and seamless operating in the same manner as a fully automatic transmission.
When the ECM, PCM or TCM detects improper voltage or resistance within the clutch actuator circuit, code P0900 will be set and the check engine light or the transmission warning lamp will be illuminated.
A clutch actuator:
What is the severity of this DTC?
The severity of this code is normally moderate, but P0900 can be severe if the vehicle is not shifting properly that may cause damage to internal transmission components.
What are some of the symptoms of the code?
Symptoms of a P0900 trouble code may include:
What are some of the common causes of the code?
Causes for this P0900 code may include:
What are some P0900 troubleshooting steps?
The first step in the troubleshooting process for any malfunction is to research the Technical Service Bulletins (TSB’s) for the specific vehicle by year, model and power plant. In some circumstances, this can save a lot of time in the long run by pointing you in the right direction.
The second step is to locate all of components associated with the clutch actuator circuit and look for obvious physical damage. Perform a thorough visual inspection to check the associated wiring for obvious defects such as scraping, rubbing, bare wires, or burn spots. Next is to check the connectors and connections for security, corrosion and damaged pins. This process must include all wiring connectors and connections to all sensors, solenoids, actuators and control modules. Consult the specific tech data for the vehicle to see if a fuse or fuse-able link is incorporated into the circuit.
Advanced Steps
The advanced steps become very vehicle specific and require the appropriate advanced equipment to perform accurately. These procedures require a digital multi meter and the specific technical references for the vehicle. Specific technical data will include troubleshooting charts and the appropriate sequence to follow assisting you with an accurate diagnosis.
Voltage Checks
Voltage checks must be performed utilizing the specific troubleshooting guidelines for the vehicle to identify the proper sequence and the acceptable ranges for proper operation. This phase of the troubleshooting process will vary tremendously for different makes and models.
If this process identifies the absence of a power source or ground, continuity testing may be required to check the integrity of the wiring, connectors and other components. Continuity tests should always be performed with the power removed from the circuit and the normal readings for wiring and connections should be 0 ohms of resistance. Resistance or no continuity is an indication of faulty wiring that is open or shorted and must be repaired or replaced. A continuity test from the ECM, PCM or TCM control to the frame will confirm the serviceability level of ground straps and ground wires. The presence of resistance is an indication of a loose connection or possible corrosion.
What are some common repairs for this code?
Common Mistake
Hopefully, the information in this article has been helpful to point you in the right direction to correct the problem with your clutch actuator circuit fault code. This article is strictly informational and the specific technical data and service bulletins for your vehicle should always take priority.
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"Delete Error Code Permanently, Disable DTC Error Code Function for p0900 in the ECU"
In extreme cases, we even have the option to permanently remove the specific DTC p0900 and disable the function of the specific error code in the ECU. All other fault code functions will then continue to work to protect the engine. This is different from clearing an error code with a diagnostic device. We have the option to permanently remove the function of the specific error code, so that it never comes back. Also emergency running that occurs on the specific error code can be solved in most cases.
Of course we prefer to first try to solve the cause of the error code, but sometimes the only solution is to permanently disable the DTC function of p0900.