P0708 Transmission range sensor “A” circuit high
OBD2 Error Codes

P0708 Transmission range sensor “A” circuit high

P0708 – OBD-II Trouble Code Technical Description

Transmission Range Sensor A Circuit High

What does the fault code mean P0708?

This diagnostic trouble code (DTC) is a generic transmission code applicable to OBD-II equipped vehicles. However, the specific repair steps may vary depending on the make and model of your vehicle. P0708 is a diagnostic trouble code in the transmission subsystem, referred to as “B”. This means that the check engine light will not come on until the conditions for setting the code are detected with two consecutive key sequences.

Example of an external transmit range sensor (TRS):

The powertrain control module (PCM) or transmission control module (TCM) uses the transmission range sensor (lockup switch) to determine the position of the shift lever. If the PCM or TCM receives signals indicating two different gear positions simultaneously for more than 30 seconds, this will cause the P0708 code to set. If this happens twice in a row, the check engine light will come on and the transmission will go into “fail-safe” or “limp” mode.

Possible reasons

Potential causes of this DTC include:

  1. Faulty transmission range sensor.
  2. Shift cable/lever adjusted incorrectly.
  3. Damaged wiring.
  4. Incorrectly configured distance sensor (rare).
  5. PCM or TCM failure.
  6. Faulty transmission range sensor.
  7. Damaged gearbox range sensor.
  8. Damaged or disconnected wiring associated with the transmission range sensor.
  9. Defective engine control unit.

What are the symptoms of a fault code? P0708?

Code P0706 is accompanied by an illuminated Check Engine Light and an apparent lack of power when coming to a complete stop as the transmission starts in third gear. Continuing to drive may damage the transmission. It is recommended that repairs be made immediately to avoid costly internal transmission repairs. Symptoms include:

  1. Check Engine light on.
  2. Obvious lack of power when coming to a complete stop.
  3. Difficult gear shifting.
  4. Transmission slipping.
  5. No gear change.
  6. Check the engine indicator light.

How to diagnose a fault code P0708?

The mechanic will begin diagnosing the P0708 trouble code by performing the transmission range sensor adjustment procedure per the manufacturer's recommendations. If the adjustment does not solve the problem, the mechanic will check the transmission range sensor and wiring for problems.

If during the diagnostic process it is revealed that the sensor or any wires in the circuit are faulty, they will need to be replaced. If all of these components are working properly, there may be a problem with the engine control module (PCM/TCM).

The transmission range sensor receives power from the ignition switch and sends a signal back to the PCM/TCM indicating the current shift lever position. The most common causes of a P0708 code are a faulty range sensor or improper shift cable/lever adjustment. You can check the condition of this circuit using a digital volt-ohmmeter by checking the voltage at the sensor while shifting gears. If voltage is present in more than one position, this may indicate a faulty sensor.

Although a PCM/TCM malfunction is possible, it is an unlikely cause of range sensor related DTCs.

Diagnostic errors

Article paragraph error when diagnosing P0708:

When diagnosing the P0708 code, many mechanics sometimes make the following mistakes:

  1. Skipping the Transmission Range Sensor Adjustment Test: Sometimes mechanics may skip or not perform the transmission range sensor adjustment procedure carefully, which can lead to a misdiagnosis.
  2. Replacing Components Without Further Checking: If a P0708 code is detected, mechanics can immediately replace components such as the transmission range sensor or wiring without further checking for other potential causes.
  3. Skipping a PCM/TCM Check: Sometimes diagnostics are limited to only the components associated with the P0708 code, and mechanics may skip checking the engine control module (PCM) or transmission control module (TCM), which can lead to other problems being missed.
  4. Insufficient wiring check: The connection or wiring associated with the transmission range sensor may be damaged or corroded. However, mechanics may sometimes fail to sufficiently check the condition of the wiring.
  5. Confusing Similar DTCs: It is possible for mechanics to mistakenly confuse the P0708 code with other similar DTCs, which can lead to incorrect diagnosis and repairs.

To avoid these errors when diagnosing a P0708 code, mechanics must follow the manufacturer's recommended procedures, thoroughly inspect all components, and perform comprehensive diagnostics to determine the exact cause of the problem.

How serious is the fault code? P0708?

Trouble code P0708 can be considered serious because it is related to the vehicle's transmission. This code indicates problems with the transmission range sensor and can cause a variety of driving problems. For example, the car may start in the wrong gear, which can create dangerous situations on the road.

Moreover, missing an adjustment or misdiagnosing a P0708 code can lead to costly repairs such as replacing transmission components. Therefore, it is recommended to immediately contact a professional for diagnosis and repair if the P0708 code appears to avoid further problems and ensure safety on the road.

What repair will help eliminate the code? P0708?

  1. Checking and adjusting the transmission range sensor.
  2. Replacing a faulty transmission range sensor.
  3. Check and repair damaged wiring associated with the transmission range sensor.
  4. Diagnose and, if necessary, replace the engine control module (PCM) or transmission control module (TCM).
What is P0708 Engine Code [Quick Guide]

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