What Does P0708 Mean?
The TCM has detected that the Transmission Range Sensor (TRS) A circuit signal is consistently high. The sensor voltage is at or near the maximum reference voltage, indicating a possible open circuit, disconnected sensor, or short to voltage. The TCM cannot accurately determine gear position. The driver may experience a no-start condition, incorrect gear display, the transmission stuck in limp mode, or erratic shifting behavior.
Common Causes
35%
Open circuit in the TRS signal or ground wire — broken wire, disconnected connector, or corroded terminal
30%
Faulty transmission range sensor with open internal contacts or failed element
15%
Signal wire shorted to voltage supply — chafed insulation contacting a power wire
12%
TRS connector not fully seated or disconnected from the sensor
8%
TCM internal pull-up or input circuit fault
Diagnostic Steps
1
Check the TRS connector — ensure it is fully seated, the locking tab is engaged, and no pins are pushed back or corroded. A disconnected sensor will cause a high-input reading.
2
Measure voltage at the TRS connector with key ON — verify reference voltage (typically 5V) on the supply pin, ground on the ground pin, and a varying signal on the output pin as gears are selected.
3
If the signal pin reads at or near reference voltage in all gear positions, disconnect the sensor and check for continuity in the signal wire back to the TCM — an open wire will leave the signal floating high.
4
Test the TRS by measuring resistance between its terminals in each gear position — compare to manufacturer specifications. An open reading in any position indicates a failed sensor.
5
Check for short-to-voltage conditions by inspecting the wiring harness where TRS signal wires run alongside power wires — particularly near the transmission where heat and vibration can damage insulation.
Estimated Repair Cost
$75 - $400
Parts + labor, varies by vehicle and location
The TCM has detected that the Transmission Range Sensor (TRS) A circuit signal is consistently high. The sensor voltage is at or near the maximum reference voltage, indicating a possible open circuit, disconnected sensor, or short to voltage. The TCM cannot accurately determine gear position. The dr...
The most common cause of P0708 (Transmission Range Sensor A Circuit High Input) is: Open circuit in the TRS signal or ground wire — broken wire, disconnected connector, or corroded terminal
Typical repair costs for P0708 range from $75 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A stuck-high TRS signal means the TCM cannot determine gear position, which may disable the neutral safety switch, cause incorrect reverse light operation, and force the transmission into limp mode. The vehicle may not start if the TCM believes it is in gear. If drivable, proceed cautiously to a repair facility.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0708 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transmission Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
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