P07B4 Transmission Park Position Sensor/Switch A Circuit High
OBD-II Trouble Code Technical Description
Transmission Park Position Sensor/Switch A Circuit High
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 P07B4 is one of several possible codes associated to the Transmission Park Position Sensor/Switch "A" 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 "A" circuit malfunctions are P07B2, P07B3, P07B4, P07B5, P07B6, and P07B7. 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 "A" 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 P07B4 is set by the PCM when the transmission park position sensor/switch "A" circuit is detected as having high output voltage.
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 P07B4 trouble code may include:
Vehicle will not start (starter will not engage) Starter will engage with the vehicle in gear An illuminated Service Engine Soon Light Check Engine Light is illuminated Transmission may not shift out of park Transmission may not shift into parkWhat are some of the common causes of the code?
Causes for this P07B4 code may include:
Defective transmission park position sensor/switch Corroded or damaged connector Damaged or faulty wiring Defective PCMWhat are some P07B4 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 "A" 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
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