What Does P07B4 Mean?
The transmission park position sensor/switch "A" circuit is reading higher voltage than expected. The TCM has detected that the sensor A signal is above the normal operating range for the current transmission position. This typically indicates an open in the sensor circuit being pulled high by the reference voltage, a failed sensor with excessive internal resistance, or a short to voltage on the signal wire. The vehicle may have no-start conditions, incorrect gear display, or shift interlock problems.
Common Causes
35%
Open circuit in the park position sensor A ground or signal return path
30%
Failed park position sensor A with high internal resistance or open element
15%
Short to battery voltage on the sensor A signal wire from harness damage
15%
Corroded or loose connector at sensor A causing high-resistance connection
5%
TCM reference voltage circuit issue providing incorrect voltage to sensor A
Diagnostic Steps
1
Measure park position sensor A signal voltage at the TCM connector — a reading at or near reference voltage (typically 5V) confirms an open in the sensor or return circuit.
2
Check sensor A ground/return circuit continuity from the sensor connector to the TCM connector.
3
Disconnect the sensor and measure its resistance values through all positions — high or infinite resistance indicates sensor failure.
4
Inspect the wiring harness for damaged insulation that could allow the signal wire to contact a voltage source.
5
Verify the sensor connector is fully seated and terminals are making proper contact without corrosion or spreading.
Estimated Repair Cost
$120 - $550
Parts + labor, varies by vehicle and location
The transmission park position sensor/switch "A" circuit is reading higher voltage than expected. The TCM has detected that the sensor A signal is above the normal operating range for the current transmission position. This typically indicates an open in the sensor circuit being pulled high by the r...
The most common cause of P07B4 (Transmission Park Position Sensor/Switch "A" Circuit High) is: Open circuit in the park position sensor A ground or signal return path
Typical repair costs for P07B4 range from $120 to $550, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle may not start if Park position cannot be confirmed. Gear position display may be inaccurate, and the shift interlock may not function properly. Use caution when parking and avoid steep grades until the sensor circuit is repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P07B4 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transmission Control / Park System
Difficulty
Type
Generic (SAE)
Recommended Tools
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