Technical Description of OBD-II Trouble Code
Circuit for Clutch Position Sensor
What does that signify?
This is a generic diagnostic trouble code (DTC) for the powertrain and is applicable to many OBD-II vehicles (1996-newer). This includes vehicles from various manufacturers such as Dodge, Ford (Focus, Fiesta, etc), Smart, Land Rover, Chevrolet, Chrysler, Jeep, Mercedes, Toyota, etc. Although it is a generic code, the specific repair steps may vary depending on the year, make, model, and powertrain configuration.
OBD-II trouble code P0805 and related codes P0806, P0807, P0808, P0809, and P080A are associated with the circuit for the clutch position sensor. The Power Control Module (PCM) or the Transmission Control Module (TCM) monitors this circuit based on the specific vehicle.
The purpose of the clutch position sensor circuit is to monitor the status of the clutch on a manual transmission. This is done by reading the output voltage of the clutch position sensor, which indicates when the clutch is engaged. In most cases, the clutch position sensor is a basic on/off switch mounted near the clutch foot pedal on the support bracket. One side of the switch typically has constant voltage, and the contacts are closed by engaging the clutch, transferring voltage to the starter or starter solenoid. This basic circuit and switch prevent the engine from starting before the clutch is engaged.
When the PCM or TCM detects improper voltage or resistance within the clutch position sensor circuit, code P0805 is set and the check engine light or the transmission warning lamp is illuminated.
A clutch position sensor:
What is the severity of this DTC?
Normally, the severity of this code is moderate, but P0805 can be severe if the vehicle starts with the clutch disengaged, creating a safety issue.
What are some of the symptoms of the code?
Symptoms of a P0805 trouble code may include:
What are some of the common causes of the code?
Causes for this P0805 code may include:
What are some P0805 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 cases, this can save a lot of time in the long run by pointing you in the right direction.
The second step is to locate the clutch position sensor switch 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, check the connectors and connections for security, corrosion, and damaged pins. This process must include all wiring connectors and connections to the clutch position sensor switch, PCM, starter, and the starter solenoid. 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 multimeter 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
When the clutch is disengaged, there should be approximately 12 volts on one side of the sensor. When the clutch is engaged, you should have voltage on both sides of the sensor. The starter solenoid or starter should also have power based on the configuration.
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 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 in pointing you in the right direction to correct the problem with your clutch position sensor circuit fault code. This article is strictly informational, and the specific technical data and service bulletins for your vehicle should always take priority.
