P07B8 Transmission Park Position Sensor/Switch “B” Circuit Open
OBD-II Trouble Code Technical Description
Transmission Park Position Sensor/Switch B Circuit Open
What does that mean?
This is a generic powertrain diagnostic trouble code (DTC) and applies to OBD-II vehicles that have a transmission park position switch/sensor. That may include but is not limited to vehicles from Dodge, Ford, Toyota, Land Rover, VW, Chevrolet, etc. Although generic, the exact repair steps may vary depending on year, make, model and powertrain configuration.
Trouble code P07B8 is one of several possible codes associated to the Transmission Park Position Sensor/Switch "B" Circuit.
This code is an indication that the Powertrain Control Module (PCM) has detected a malfunction that is affecting the operation of the transmission park position sensor/switch "B" circuit. The codes that are commonly associated to transmission park position sensor/switch "B" circuit malfunctions are P07B8, P07B9, P07BA, P07BB, P07BC and P07BD. The specific situation determines the code activated by the PCM and the check engine light or the service engine soon light will be illuminated.
The purpose of the transmission park position sensor/switch "B" circuit is to monitor the status of the transmission. This circuit sends a signal to the PCM when the transmission is placed into the park position. Based on the specific vehicle, this circuit is commonly a safety feature to prevent the starter from engaging with the automatic transmission in gear.
Code P07B8 is set by the PCM when the transmission park position sensor/switch "B" circuit is detected as having an open circuit.
What is the severity of this DTC?
The severity of this code varies based on the specific malfunction and the severity level may progress if not corrected in a timely manner. This code could become a safety issue requiring immediate attention if the starter will engage with the vehicle in gear.
Photo of a park/neutral position switch:
What are some of the symptoms of the code?
Symptoms of a P07B8 trouble code may include:
What are some of the common causes of the code?
Causes for this P07B8 code may include:
What are some P07B8 troubleshooting steps?
The first step in the troubleshooting process for any malfunction is to research the Technical Service Bulletins for known issues with the specific vehicle.
Locate all of the components associated with the transmission park position sensor/switch "B" circuit. This will include the transmission park position sensor/switch, wiring, connectors and the PCM on a simplex system. Based on the specific year, make and model of the vehicle this circuit may incorporate more components. After these components are located, a thorough visual inspection should be conducted to check all of the associated wiring and connectors for obvious defects such as scraping, rubbing, bare wires or burn spots. The connectors should also be checked for corrosion build up or damaged pins.
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. Voltage requirements will vary based of the specific year, make and model of the vehicle.
Circuit Checks
Voltage requirements will vary based on the specific vehicle, the transmission park position sensor/switch circuit configuration and the components incorporated. Technical data should be referenced to obtain the correct voltage range for the transmission park position sensor/switch and the appropriate troubleshooting sequence to follow. The correct voltage input to a sensor/switch with no voltage output is normally an indication of internal failure.
If this process identifies the absence of a power source or ground, continuity testing may be needed to check the condition of the wiring and connectors. Continuity tests are always performed with the power removed from the circuit and the normal readings should be 0 ohms of resistance unless otherwise specified by the technical data. Resistance or no continuity is an indication of faulty wiring or connectors that are shorted or open and must be repaired or replaced.
Common Repairs
Hopefully, the information in this article has been helpful to point you in the right direction to correct the problem with your the transmission park position sensor/switch circuit. 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 p07b8 in the ECU"
In extreme cases, we even have the option to permanently remove the specific DTC p07b8 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 p07b8.
