P0708 on 2012-2019 Hyundai Accent: Transmission Range Sensor Failure Causes and Fixes

What's Unique About the 2012-2019 Hyundai ACCENT

For this generation of Hyundai Accent, the transmission range sensor (inhibitor switch) is a well-documented point of failure. Hyundai has issued multiple Technical Service Bulletins (TSBs) that cover this exact code and the associated family of range sensor codes (P0705, P0706, P0707) across many models sharing the same 6-speed automatic transmission, including the Accent. This indicates a known pattern of issues with the sensor or its related circuitry rather than a random, isolated fault. The part is shared across a wide range of Hyundai and Kia vehicles, making it a very common failure item.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Generation note: The 2012-2019 range covers the end of the fourth generation (RB, 2012-2017) and the beginning of the fifth generation (YC, 2018-2019). While both generations can experience this code, the specific part number for the inhibitor switch may differ. For the 6-speed automatic common in the RB generation, the part is typically 42700-26000. Later models with CVT transmissions (starting in the YC generation) may use a different switch. Always verify the part number with your vehicle's VIN.

Symptoms You May Notice

• Check Engine Light (Malfunction Indicator Lamp) is on.
• Transmission stuck in a single gear (fail-safe mode, often 3rd or 4th gear).
• Vehicle will not start or has an intermittent no-start condition, especially when warm.
• No gear position (PRNDL) displayed on the instrument cluster, or the indicator is incorrect/erratic.
• Harsh or delayed shifting into gear.
• Reduced engine power or poor acceleration due to being in a high gear.
• Inability to shift out of Park.
🎬 Watch: Common causes and fixes for the P0708 code

Most Likely Causes

1. Faulty Transmission Range Sensor (Inhibitor Switch) 🔴 High Probability This is a known high-failure item documented in Hyundai TSBs #19-AT-024H and #17-AT-005, indicating a common failure point for this component across many Hyundai/Kia models. The sensor is exposed to heat and the elements on the outside of the transmission, leading to internal failure.
   How to confirm: Use a scan tool to monitor the sensor's output data while moving the gear selector. If the data is erratic, shows multiple gears at once, or doesn't match the selected gear, the sensor is bad. Electrical testing of the sensor's pins for correct voltage and resistance against a service manual's specifications can also confirm failure.
   Typical fix: Replace the transmission range sensor/inhibitor switch. This is the most common repair. A YouTube video by 'kiko mekaniko' shows the process on a 2014 Accent.
   Est. part cost: $45-$100
2. Damaged Wiring or Corroded Connector 🟡 Medium Probability The sensor is located on the top/front of the transmission, under the battery and airbox, exposing its wiring and connector to moisture, heat, and potential chafing which can lead to corrosion or damage over time.
   How to confirm: Visually inspect the wiring harness and connector leading to the inhibitor switch for any signs of corrosion, green crust, frayed wires, or loose pins. Perform a continuity and voltage drop test on the circuit between the sensor and the TCM/PCM.
   Typical fix: Clean the connector terminals with electrical contact cleaner or repair/replace the damaged section of the wiring harness. In one Reddit thread, a user found a wire was simply unclipped and tucked away, causing the code.
   Est. part cost: $10-$50
3. Misadjusted Shift Cable or Sensor ⚪ Low Probability While less common than outright failure, the shift linkage cable can stretch or the sensor's mounting bolts can become loose, causing a misalignment between the gear selector's physical position and the sensor's electrical reading.
   How to confirm: Check if the gear indicated on the dashboard matches the physical position of the shifter. TSB #17-AT-005 details the alignment procedure, which involves placing the shifter in Neutral and using a 5mm bolt or guide pin (SST 09480-A3800) to align the switch before tightening the bolts.
   Typical fix: Adjust the shift cable and/or realign the inhibitor switch and tighten its mounting bolts to the correct torque.
   Est. part cost: $0

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM) or Transmission Control Module (TCM): This is very rare and should only be considered after the sensor, wiring, and adjustment have been definitively ruled out. TSBs instruct to replace the PCM/TCM only if the DTC returns after replacing the sensor and verifying the wiring is good. Unnecessarily replacing the PCM/TCM is an expensive mistake.

Diagnosis Steps

1. Connect an OBD-II scanner and confirm P0708 is present. Check for other related transmission codes like P0705, P0706, P0707.
2. Access the live data stream on the scanner. Observe the Transmission Range Sensor parameter (may be listed as TR Switch, etc.) while slowly moving the gear selector through all positions (P, R, N, D).
3. Note any positions where the scanner shows an invalid signal, multiple gears selected at once, or a gear that doesn't match the shifter position. This strongly suggests a faulty sensor.
4. Perform a visual inspection. Following TSB procedures, remove the air cleaner assembly and battery/battery tray to access the inhibitor switch on top of the transmission. Check its electrical connector and wiring for corrosion, damage, or looseness.
5. Check the adjustment of the shift cable and the sensor itself. With the transmission in Neutral, check if a 5mm bolt can be inserted into the alignment hole on the switch as per TSB 17-AT-005.
6. If wiring and adjustment are good, test the sensor directly. Disconnect the sensor and use a digital multimeter to check for correct power supply voltage (around 12V) on the harness side and test for resistance/continuity across the sensor's terminals according to the vehicle's service manual specifications as you move the lever.
🎬 See how to test and replace the inhibitor switch
7. If the sensor fails the electrical tests or live data was erratic, it needs to be replaced.
8. If the sensor and wiring test good, the fault may lie with the TCM/PCM, which requires advanced diagnostics.

Parts You'll Likely Need

• Transmission Range Sensor / Inhibitor Switch (OEM #42700-26000) — This is the component that fails most frequently, causing the P0708 code by sending incorrect gear position data to the vehicle's computer. It is a widely used part across many Hyundai and Kia vehicles.
  Trusted brands: Hyundai (Genuine), Standard Motor Products, Dorman, X AUTOHAUX, Unique Bargains
  OEM price range: $80-$125
  Aftermarket price range: $45-$90

Related Codes That Often Appear With This One

• P0705 — This code indicates a general circuit malfunction for the same sensor and is listed in the same TSBs.
• P0706 — This code indicates a range/performance problem with the sensor, often due to misalignment.
• P0707 — This code indicates a low input (open circuit) from the sensor, the opposite of P0708.

Technical Service Bulletins (TSBs) & Recalls

• 19-AT-024H: Supersedes the earlier TSB. Lists applicable vehicles including the 2012-17 Accent (RB) and 2018+ Accent (HC). Confirms symptoms like 4th gear fail-safe and no-start for P0708.
• 17-AT-005: Provides a detailed diagnostic and replacement procedure for the inhibitor switch related to codes P0705-P0708. Details the alignment procedure using a 5mm bolt in the Neutral position.
• 5NP-V3F8T-09: An equipment TSB that also lists P0708 with

Platform-Specific Known Issues

• TSB Confirmed High Failure Rate: Hyundai has released Technical Service Bulletin 19-AT-024H, which supersedes 17-AT-005. It directly addresses P0708 ('Range switch - short circuit or multiple inputs') and lists symptoms including MIL illumination, 4th gear fail-safe, no gear indication, and intermittent no-start. This confirms the manufacturer is aware of the problem across many models, including the Accent.
• Owner Repair Story: Intermittent No-Start: On Reddit, an owner of a 2015 Accent described an intermittent no-start issue where the car would fail to start at work but would start again after being towed to the mechanic. While no codes were mentioned in this specific post, this behavior is a classic symptom of a failing inhibitor switch that is heat-sensitive, a condition described in TSB 17-AT-005.

Mechanic-Grade Diagnostic Values

• Inhibitor Switch Multi-Signal Voltage Test — expected: The switch sends a 12V (battery voltage) signal to the TCM on separate, dedicated wires for each gear position. Only ONE signal wire should show 12V at a time, corresponding to the selected gear. All other signal wires should read 0V.. Failure: Code P0708 is set when the TCM detects 12V on multiple signal wires simultaneously for more than a few seconds (e.g., it sees a signal for both 'Drive' and 'Reverse' at the same time).
• Inhibitor Switch Bench Test (Continuity) — expected: With the switch removed, use a multimeter on the resistance (Ohms) setting. There should be continuity (near 0 Ω) between the main power input pin and only one corresponding output pin for each gear position as you manually move the selector.. Failure: No continuity on a selected gear's pin, or continuity on multiple output pins at once, indicates internal failure of the switch.

Scan Tool Commands That Help

• Hyundai GDS (G-Scan) or equivalent professional scanner: Resetting automatic transmission adaptive values — This function should be performed after replacing the transmission range sensor or performing any significant transmission repair. It clears the TCM's learned shift data, allowing it to adapt to the new component correctly. The procedure typically requires Key On, Engine Off, and the shifter in Park.

Real Owner Repair Stories

• hyundai-forums.com user 'davesrb' (2012 Hyundai Accent) — Check engine light on with code P0708, transmission stuck in 3rd gear (fail-safe mode).
  ✅ What actually fixed it The user replaced the inhibitor switch, which resolved all symptoms and cleared the code. The user noted the job was 'not too bad' to perform.
• YouTube channel 'kiko mekaniko' (2014 Hyundai Accent) — Check engine light on with code P0708.
  ❌ Tried (didn't work) Initial diagnosis and inspection of wiring.
  ✅ What actually fixed it The problem was fixed by replacing the transmission range sensor (inhibitor switch). The multi-part video series shows the complete diagnosis and replacement process.

OEM Part Supersession History

• 42700-26000 → 42700-26500, and subsequently 42700-26700 — Standard part revision and consolidation by the manufacturer.
  Heads up: The latest part number, 42700-26700, replaces the previous versions including 42700-26000 and 42700-26500. Always use the latest available part number when ordering.

Model Year Variations Within This Range

• 2012-2017: The fourth generation (RB) Accent primarily used the A6GF1 6-speed automatic transmission. This transmission is a well-documented platform where this inhibitor switch failure is common.