P0705 on 2006-2013 Chevrolet Impala: Transmission Range Sensor Failure Causes and Fixes

What's Unique About the 2006-2013 Chevrolet Impala

For the ninth-generation Impala (2006-2013), the P0705 code is a very common issue that typically points directly to the external Transmission Range Sensor (TRS). Unlike later Impala models (2014+) where the sensor is located inside the transmission and is difficult to service, the sensor on this platform is mounted on top of the 4T65-E automatic transmission case. This makes it accessible from the engine bay, turning a potentially complex transmission issue into a manageable DIY repair for many owners.

Generation note: The 2006-2013 year range covers the entire ninth generation of the Chevrolet Impala. The information in this guide is specific to these models, which primarily used the 4T65-E 4-speed automatic transmission. This issue is also common on other GM W-body vehicles that use the same transmission.

Symptoms You May Notice

• Check Engine Light is on.
• Engine will not start, or will only start in Neutral instead of Park.
• The need to jiggle the shifter to get the car to start.
• Incorrect gear selection displayed on the dashboard (PRNDL indicator), may be blank or flash.
• Harsh, delayed, or erratic shifting between gears.
• Transmission gets stuck in one gear (limp mode).
• Reverse lights do not turn on when the vehicle is in Reverse.
• The key may become stuck in the ignition.
• Reduced engine power warning light may illuminate.

Most Likely Causes

1. Failed Transmission Range Sensor (Neutral Safety Switch) 🔴 High Probability → Shop Transmission Assembly The sensor is an electronic component with internal moving parts that wears out over time from heat, vibration, and thousands of shifts. Its location on the transmission can also expose it to moisture, road salt, and grime, leading to internal corrosion and failure.
   How to confirm: Use a scan tool to monitor the sensor's output data while moving the shifter. If the displayed gear does not match the shifter's position, or if the signal is erratic, the sensor is likely faulty. You can also perform a "wiggle test": if the car starts in Neutral but not Park, or only starts when you jiggle the shifter, the sensor is the prime suspect.
   Typical fix: Replace the Transmission Range Sensor. The new sensor must be properly aligned during installation. Many aftermarket parts come with a small plastic alignment pin to ensure it's installed in the neutral position.
   Est. part cost: $30-$75
2. Damaged Wiring or Corroded Connector 🟡 Medium Probability The wiring harness and connector for the sensor are located in the engine bay and can be exposed to heat, moisture, and road debris, leading to corrosion on the pins or breaks in the wires. The plastic connector can become brittle and crack over time.
   How to confirm: Visually inspect the electrical connector and wiring going to the Transmission Range Sensor. Look for green or white corrosion on the pins, frayed or chafed wires, or loose connections. Unplug the connector and check for moisture or damage inside. A manufacturer service bulletin for another GM model, TSB Bulletin #PIP5101, notes that technicians should specifically inspect the Park Neutral Position connector for spread terminals, bent pins, or damaged weather seals when P0705 is present.
   Typical fix: Clean the connector terminals with an electrical contact cleaner or repair/replace the damaged section of the wiring harness. Dielectric grease should be applied to the new connection to prevent future moisture intrusion.
   Est. part cost: $5-$50
3. Misadjusted Transmission Range Sensor or Shift Linkage ⚪ Low Probability → Shop Transmission Assembly While less common, the sensor can become loose over time, or the shift cable linkage can get out of adjustment, causing a mismatch between the physical gear selection and the sensor's reading. This is more likely if the sensor or transmission has been recently serviced.
   How to confirm: Check that the shift lever on the transmission moves fully into each gear detent as the shifter inside the car is moved. Verify the sensor's mounting bolts are tight. Alignment is often checked by ensuring the car starts only in Park and Neutral and that the reverse lights work only in Reverse.
   Typical fix: Loosen the sensor's mounting bolts and rotate it slightly to align it correctly, then retighten. Adjust the shift cable if necessary.
   Est. part cost: $0

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM) or Transmission Control Module (TCM): → Shop Transmission Assembly This is very rare. Before suspecting the control module, all other causes (sensor, wiring, adjustment) should be thoroughly ruled out. A faulty module will typically be accompanied by multiple other trouble codes and communication errors.

Diagnosis Steps

1. Read the codes with an OBD-II scanner. Confirm P0705 is present, and note any other codes like P0700.
2. Perform a "wiggle test": Try to start the car in Neutral. If it starts in Neutral but not Park, or if you can get it to start by jiggling the gear shifter, the Transmission Range Sensor is almost certainly the issue.
3. Locate the Transmission Range Sensor. On the 2006-2013 Impala, it is on the top of the transmission case, under the air filter housing, where the shift cable lever attaches.
4. Visually inspect the sensor's electrical connector and wiring harness for any signs of corrosion, damage, or loose connections. Pay close attention to the pins inside the connector for any green or white powder.
5. If a scan tool with live data is available, monitor the PRNDL input signal as you move the shifter through each gear. The reading on the scan tool should match the gear you select. If it's incorrect, erratic, or doesn't change, the sensor is bad.
6. If the wiring looks good and the sensor is suspected, the next step is replacement. Disconnect the battery before starting work.
7. After replacement, ensure the new sensor is properly aligned. Many replacement parts come with an alignment pin for this purpose. A common method is to place the transmission in Neutral, align the marks on the sensor and transmission, and then tighten the bolts.
8. Clear the trouble codes and test drive the vehicle, ensuring it starts correctly in Park and Neutral, the reverse lights work, and the gear indicator is accurate.

Parts You'll Likely Need

• Transmission Range Sensor / Neutral Safety Switch (OEM #24229422) — This sensor is the most common point of failure for the P0705 code on this vehicle due to electronic wear and tear. The OEM part number 24229422 has been superseded by 24298931.
  Trusted brands: ACDelco (GM Original Equipment), Standard Motor Products (SMP), Dorman
  OEM price range: $60-$90
  Aftermarket price range: $30-$50

Related Codes That Often Appear With This One

• P0700 — P0700 is a generic code that means the Transmission Control Module (TCM) has requested the Check Engine Light to be turned on. It acts as a general flag for a transmission-related fault and will almost always appear alongside a more specific code like P0705.

Platform-Specific Known Issues

• No specific recalls or Technical Service Bulletins (TSBs) were found for the P0705 code or the Transmission Range Sensor on the 2006-2013 Impala. However, failure of this part is a widely documented and common repair among owners in online forums.
• Owner Experience: A user on a Reddit auto repair forum experienced a P0705 code after incorrectly tapping into a wire in a 20-pin connector while installing another accessory, suggesting that damaging nearby wiring can also trigger this specific code.

Mechanic-Grade Diagnostic Values

• Transmission Range Sensor Bench Test — expected: Using a multimeter set to resistance (Ohms), there should be continuity between the main power feed pin and the specific pin for the selected gear as the switch is manually moved through its positions. The resistance should be low when a gear is selected and infinite (Open Line) when it is not.. Failure: No continuity on a selected gear's pin, or continuity on multiple gear pins at the same time, indicates a failed sensor.
• Transmission Range Sensor Voltage (Back-probing at connector) — expected: With the key on, engine off, back-probing the signal wires at the sensor connector should show a specific voltage for each gear position. The exact voltage varies, but it should change distinctly as the shifter is moved through P, R, N, D, etc.. Failure: Voltage that remains constant, is stuck low (e.g., below 0.5V), or is absent when moving the shifter points to a bad sensor or a wiring issue.

Scan Tool Commands That Help

• Tech2 / GDS2 or equivalent bidirectional scanner: Live Data Display for 'Shift Lever Switch' or 'PRNDL Input' — This is a primary diagnostic step. It allows the technician to see exactly what gear position the Powertrain Control Module (PCM) or Transmission Control Module (TCM) is reading from the sensor. If the displayed gear on the scan tool does not match the physical position of the gear shifter, it confirms a fault in the sensor, its adjustment, or the wiring.

Wiring & Ground Locations

• G101 — Located at the front of the engine, on the lower block.. This ground point serves the Engine Control Module (ECM) and the Transmission Control Module (TCM), as well as the Park/Neutral Position Switch itself. A corroded or loose G101 ground can cause erratic signals and communication issues between these components, potentially triggering a P0705 code even if the sensor and wiring harness are intact.
• Transmission Wiring Harness — Runs from the transmission, often alongside the engine head and near the exhaust manifold, to the control modules.. On some GM vehicles, this harness is routed close to high-heat sources like the cylinder head and exhaust. Over time, the protective loom can degrade, allowing wires to melt and short together, causing a P0705 code without any fault in the sensor itself.

Real Owner Repair Stories

• YouTube video from 'Top 5 Auto Repairs' (General GM Truck (demonstrates a common GM issue)) — Check Engine Light with code P0705.
  ❌ Tried (didn't work) The vehicle owner replaced the Transmission Range Sensor twice, assuming the first aftermarket part was defective.
  ✅ What actually fixed it The wiring harness running alongside the engine head had been damaged by heat from the engine and exhaust. The protective loom had disintegrated, causing several wires to melt and stick together, creating a short circuit. The fix was to manually separate the melted wires, inspect for bare spots, and re-wrap the harness in new loom, securing it away from the heat source.

OEM Part Supersession History

• 24229422 → 24298931 — Standard part update by the manufacturer (GM).
  Heads up: No incompatibility issues have been noted. The new part number is a direct replacement for the original.

Model Year Variations Within This Range

• 2012-2013: In 2012, the 3.6L LFX V6 engine was introduced alongside a new 6-speed automatic transmission (the 6T70). Impalas with this powertrain have the Transmission Range Sensor (called an Internal Mode Switch or IMS) located inside the transmission on the valve body. This makes replacement significantly more difficult and expensive than on the 2006-2011 models (and 2012-2013 models with the 3.5L V6) that use the 4T65-E transmission with its external sensor. It is critical to identify the correct engine/transmission before ordering parts or estimating labor.

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• Transmission Pressure Control Solenoid (PCS) Failure 🔴 High → Shop Transmission Valve Body — Common over 75,000 miles, causes harsh/erratic shifting, slips, and can set code P1811.
• HVAC Blend Door Actuator Failure 🟡 Low — Extremely common. Results in a loud clicking/ticking noise from the dashboard when changing temperature or airflow mode.
• Intermediate Steering Shaft Clunk 🟠 Medium — Common issue causing a clunking noise and feel in the steering wheel, especially at low speeds on rough surfaces. Requires replacing the intermediate shaft with an updated part. (Ref: GM TSB #00-02-35-003N)
• Excessive Engine Oil Consumption 🔴 High — Reported on some engines, particularly early in the generation, often due to worn piston rings or valve seals. Can lead to engine damage if not monitored.
• Power Steering Rack/Pump Leaks 🟠 Medium — Leaks can develop in the power steering rack (leaking into the boots without dripping on the ground) or from the pump itself, causing whining noises and steering chatter.
• Intake Manifold Gasket Leak 🟠 Medium — A known issue, particularly on the 3.4L V6, where the gasket can degrade and leak coolant or oil.

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: For the external sensor on the 4T65-E transmission (most 2006-2013 models), a used OEM part from a low-mileage donor vehicle is a reasonable choice. The part is relatively simple and failure is often due to wear or corrosion, which can be visually inspected. It can be a cost-effective alternative to a new aftermarket part of questionable quality.

Donor-vehicle mileage cap: roughly under 80000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• Check the electrical connector pins for any signs of green or white corrosion.
• Inspect the plastic housing for cracks, especially around the mounting points.
• Ensure the manual shift lever shaft is not bent or excessively worn.
• If possible, ask for the donor vehicle's mileage and avoid parts from high-mileage cars from regions with heavy road salt usage.

OEM-only on this vehicle (don't cheap out):

• While not strictly 'OEM-only', the ACDelco (GM's OEM brand) sensor is highly recommended by mechanics and forum users for reliability. Some aftermarket brands have higher failure rates.

Aftermarket brands forum-validated for this vehicle:

• Standard Motor Products (SMP)
• ACDelco (OEM)

Brands owners have reported issues with on this vehicle:

• Unbranded, 'white-box' parts sold on online marketplaces are often cited as having poor quality control and a short lifespan.

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• P0700 — A general transmission control system malfunction code that often appears alongside P0705 to indicate the TCM has requested the MIL illumination.
• P1811 — Related to maximum adapt and long shifts; often associated with the 4T65-E transmission's pressure control solenoid failure, which shares the same transmission housing as the range sensor.

Frequently Asked Questions