P0708 — Transmission Range Sensor “A” Circuit High #

Note: The label and description for DTC P0708 may vary depending on the vehicle manufacturer.

• P0708 – Transmission Range Sensor “A” Circuit High Input (General/SAE)
• P0708 – Transmission Range Sensor Circuit High Input (Ford, Mazda, Kia, Hyundai)
• P0708 – Transmission Range Switch Circuit High (Nissan, Infiniti)
• P0708 – Transmission Range Sensor ‘A’ Circuit High (Honda, Acura, Toyota, Lexus)

Summary of DTC P0708 #

P0708 is a generic OBD-II trouble code that indicates a high voltage condition in the circuit for the Transmission Range Sensor “A”, also known as the neutral safety switch or PRNDL sensor. This sensor tells the Transmission Control Module (TCM) or Powertrain Control Module (PCM) which gear the transmission is in (Park, Reverse, Neutral, Drive, Low). When the sensor signal is higher than the OEM’s expected range, it can cause confusion in gear selection, safety interlock failures, and erratic transmission behavior. This fault can lead to drivability issues and, in some cases, prevent the vehicle from starting or shifting properly. Prompt diagnosis and repair are advised to avoid further complications.

Common Symptoms for DTC P0708 #

When P0708 is present, the vehicle may exhibit a range of noticeable symptoms. In some cases, the issues are subtle, but more severe cases can impact basic operations, like starting or shifting. Keep an eye out for these warning signs:

• Transmission stuck in a single gear (often “limp” mode)
• PRNDL indicator (gear selector display) not matching shifter position
• No start condition (especially in Park or Neutral)
• Reverse lights not working as expected
• Check Engine Light (CEL) illuminated
• Harsh or delayed shifting
• Intermittent transmission operation or gear “hunting”

Probable Causes for DTC P0708 #

This code is most often triggered by electrical or mechanical faults involving the Transmission Range Sensor (TRS) circuit, but other related issues can also be responsible. Causes are listed by likelihood:

1. Faulty or misadjusted Transmission Range Sensor (TRS)
2. Damaged, shorted, or corroded wiring/connectors in the TRS circuit
3. Faulty PCM/TCM (rare)
4. Water intrusion or contamination in the sensor area
5. Mechanical misalignment of the shifter or linkage
6. Aftermarket remote start or alarm interfering with TRS circuit

Step-by-Step Diagnostic for P0708 #

Accurate diagnosis is vital to avoid unnecessary part replacements. Here’s a structured approach, suitable for both DIYers and professionals:

• 1. Scan and Record Codes: Use a scan tool to confirm P0708 and check for related transmission or gear selector codes.
• 2. Visual Inspection: Examine the TRS and its connectors for damage, corrosion, or water intrusion. Check for pinched or frayed wires.
• 3. Check TRS Adjustment: Ensure the transmission range sensor is properly aligned according to OEM specifications.
• 4. Test Circuit Voltage: With a multimeter, measure the voltage at the sensor’s signal wire. High voltage (often over 5V) indicates a short to power or an internal sensor fault.
• 5. Continuity and Short Testing: With ignition off, check wiring from the TRS to the PCM/TCM for continuity, shorts to power/ground, and proper resistance.
• 6. Sensor Replacement (if needed): If the sensor or wiring is faulty, replace or repair as necessary. Always use OEM or OEM-quality components.
• 7. Re-learn/Reset Procedures: After repairs, clear codes and perform any required transmission range calibration or re-learn procedure as per the vehicle’s service manual.

Possible Repairs for DTC P0708 #

Depending on the root cause, repairs may be simple or require parts replacement. Here are the most effective solutions:

• Repair or replace damaged TRS wiring/connectors
• Replace faulty Transmission Range Sensor with OEM or OEM-quality part
• Clean and dry connectors if water intrusion or corrosion is present
• Adjust or realign the sensor or shifter linkage as per OEM procedure
• Reprogram or update the PCM/TCM if required by Technical Service Bulletin (TSB)
• Fix any interfering aftermarket electrical accessories

Is It Safe to Drive with P0708? #

Driving with P0708 is generally not recommended. While some vehicles may allow limited mobility (such as limp mode), you risk unpredictable shifting, inability to start, or being stuck in an undesired gear. These issues can compromise safety, especially in high-traffic or hilly environments. If the vehicle only displays a check engine light without driveability issues, short-distance driving to a repair facility is possible, but avoid regular use until fixed.

Vehicles Most Commonly Affected by P0708 #

P0708 appears across multiple brands and models, particularly those using electronic transmissions with range sensors. Vehicles with high mileage or exposure to harsh climates are more susceptible. Some frequently affected makes include:

• Ford F-Series (F-150, F-250, etc.)
• Honda Accord, CR-V, Odyssey
• Hyundai Sonata, Santa Fe
• Kia Sorento, Optima
• Nissan Altima, Maxima, Pathfinder
• Toyota Camry, Tacoma, Corolla
• Chevrolet Silverado, Malibu

Common Mistakes & Best Practices for P0708 #

Misdiagnosing P0708 can lead to wasted time and money. Here are errors to avoid and tips for success:

• Replacing the sensor before inspecting wiring and connectors
• Ignoring the need for adjustment or alignment after sensor replacement
• Not checking for water intrusion or corrosion in the plug/connector
• Skipping re-learn or reset procedures after the repair
• Overlooking TSBs or software updates issued by the OEM

Quick FAQ for DTC P0708 #

Q: Can a bad battery or alternator cause P0708?
A: While rare, severe voltage irregularities from a failing battery or alternator can contribute to sensor circuit issues. However, most P0708 cases are due to sensor, wiring, or alignment faults.

Q: Do I need a scan tool to fix P0708?
A: A scan tool is highly recommended for accurate diagnosis and code clearing. Some repairs (like wiring) may be done without one, but correct sensor adjustment and code reset require scan tool access.