P0722 on 2008-2012 Honda Accord: Output Speed Sensor Failure Causes and Fixes

What's Unique About the 2008-2012 Honda Accord

The 2008-2012 eighth-generation Honda Accord, whether equipped with the 4-cylinder (K24Z) or V6 (J35Z) engine, uses an externally mounted output speed sensor (Honda Part No. 28820-RWE-003) that is a common failure point over time due to heat and vibration. While Honda transmissions of this era are generally reliable, this electronic sensor is a known weak spot. The fix is almost always replacing the sensor itself, which is accessible from the top of the engine bay, rather than indicating a more serious internal transmission failure. This issue is not caused by internal mechanical transmission problems, but is purely electrical in nature.

Symptoms You May Notice

• Check Engine Light is on
• Flashing 'D' (Drive) indicator light on the dashboard
• Harsh, erratic, or delayed gear shifts
• Transmission is stuck in a single gear (often 2nd or 3rd)
• Speedometer reads 0 mph or behaves erratically
• Cruise control does not work
• A feeling of the transmission slipping
• Inability to shift into Park while the engine is running

Most Likely Causes

1. Failed Output/Countershaft Speed Sensor 🔴 High Probability The sensor is an electronic component mounted on the transmission that is subject to constant heat and vibration, causing it to fail electrically over time. It is a very common failure point on this platform and related Honda/Acura vehicles.
   How to confirm: Using a scan tool with live data, monitor the 'Output Shaft Speed' parameter while driving. If the reading stays at 0 RPM as the vehicle moves, the sensor or its circuit is faulty. The sensor itself can also be tested with a multimeter for resistance; a typical range for this type of sensor is 560-680 Ω.
   Typical fix: Replace the output speed sensor. The sensor is held in by a single 10mm bolt and requires a new O-ring upon installation. 🎬 Watch: This walkthrough shows you how to replace the sensor. The genuine Honda part is recommended, as some owners report issues with aftermarket sensors.
   Est. part cost: $25-$70
2. Damaged Wiring or Connector 🟡 Medium Probability Engine bay heat can make wiring brittle over time, and oil or fluid leaks can contaminate the electrical connector, interrupting the signal. Wires can also be damaged by rodents or chafing against other components.
   How to confirm: Visually inspect the wiring harness leading to the sensor for any signs of fraying, melting, or breaks. Disconnect the sensor and check for corrosion, moisture, or bent pins inside the connector. A multimeter can be used to check for continuity and for a reference voltage from the PCM at the connector (typically around 5 volts for a 3-wire Hall-effect sensor).
   Typical fix: Repair the damaged section of wire or clean the connector with electrical contact cleaner. If the connector itself is broken, it will need to be replaced.
   Est. part cost: $5-$50
3. Low or Dirty Transmission Fluid ⚪ Low Probability While not a direct cause of a 'no signal' fault, extremely low or contaminated fluid can cause erratic transmission behavior, including solenoid and sensor malfunctions that may trigger various codes, sometimes in conjunction with P0722. Metallic debris in the fluid can also stick to the magnetic sensor tip and block it from reading the tone ring.
   How to confirm: Check the transmission fluid level using the dipstick (engine off, on level ground). Note the fluid's color and smell; it should be reddish and not have a burnt odor. Honda transmissions are sensitive to fluid type and condition.
   Typical fix: Perform a transmission fluid drain and fill using only Honda Genuine ATF DW-1 fluid.
   Est. part cost: $40-$80

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM): This is very uncommon. Before condemning the PCM, all other possibilities (sensor, wiring, fluid) must be exhaustively ruled out by a professional. A dealership may need to check if the PCM has the latest software.

Diagnosis Steps

1. Read the trouble codes with an OBD-II scanner to confirm P0722 is present and note any other codes.
2. Check the level and condition of the automatic transmission fluid. The fluid should be at the correct level and not appear dark or burnt.
3. Locate the output speed sensor on the top of the transmission housing. For the 8th generation Accord (both 4-cyl and V6), it is accessible from the top of the engine bay. It is necessary to remove the air filter box and intake hose for access. The sensor has a grey connector and is held by a single 10mm bolt.
4. Inspect the sensor's electrical connector and wiring for any visible damage, corrosion, or loose connections.
5. If you have a capable scan tool, view the live data for 'Output Shaft Speed'. Drive the vehicle slowly (or raise the front wheels and run in gear); the RPM should increase with vehicle speed. If it remains at 0, the sensor or circuit is the problem.
6. Test the circuit: Disconnect the sensor and use a multimeter to check for a reference voltage from the PCM at the connector (typically around 5 volts) and a good ground. If voltage and ground are good, the sensor itself is the most likely culprit.
7. If no voltage is present, inspect the wiring harness for an open or short circuit between the connector and the PCM.
8. Replace the output speed sensor if it is determined to be faulty. Always use a new O-ring and lubricate it with clean transmission fluid before installation. Torque the 10mm bolt to 115 in-lbs (approx. 9.5 ft-lbs).
9. Clear the codes and perform a road test to ensure the speedometer works and the transmission shifts correctly.

Parts You'll Likely Need

• Automatic Transmission Output Speed Sensor (Countershaft Speed Sensor) (OEM #28820-RWE-003) — This sensor is the most common cause of a P0722 code, failing due to age and heat cycles. This part number fits a wide range of Honda and Acura models from this era.
  Trusted brands: Honda Genuine, NTK, Denso, Standard Motor Products (SMP)
  OEM price range: $110-$170
  Aftermarket price range: $25-$70

Related Codes That Often Appear With This One

• P0721 — This code indicates an intermittent or irrational signal ('Performance/Range') from the same output speed sensor, and can appear alongside or instead of P0722.
• P0717 — This code points to a 'No Signal' fault from the Input (Mainshaft) Speed Sensor. Since both sensors work together to determine gear ratio, a fault in one can sometimes be flagged with a fault in the other, or indicate a wiring harness issue common to both.
• P0767 — This code for 'Shift Solenoid D Stuck On' has been reported by owners alongside P0722. The PCM's inability to see the output speed can cause it to lose track of the transmission's state, leading to solenoid-related codes. Fixing the P0722 issue often resolves the solenoid code.

Technical Service Bulletins (TSBs) & Recalls

• While no TSBs exist specifically for P0722 on this Accord, Hyundai TSB 13-AT-014-1 for similar codes (P0717, P0721, P0722) on their vehicles outlines a detailed diagnostic procedure that is generally applicable. It emphasizes checking live data, inspecting wiring, and provides steps for sensor replacement, confirming this is a standard diagnostic path.
• A TSB for Hyundai (14-AT-013) also explicitly states *not* to replace the transmission for these codes, but to follow the procedure to replace the related sensor, reinforcing that this is a sensor/electrical issue, not a major mechanical one.

Platform-Specific Known Issues

• On both the 4-cylinder and V6 models, the sensor is located on top of the transmission and requires removing the air intake assembly for access. A YouTuber demonstrated this repair, also showing the need to unbolt and move the fuse box aside for better access.
• While the cause is almost always the sensor or wiring, at least one owner on a forum reported replacing the sensor with an OEM part and still having the issue, which the dealer then suspected was a wiring problem.

Mechanic-Grade Diagnostic Values

• Output Speed Sensor (2-wire VR type) internal resistance — expected: 560 to 680 Ω at 68°F (20°C). Failure: Infinite resistance (open circuit) or near 0 Ω (short circuit).
• Reference Voltage at Sensor Connector (3-wire Hall-effect type) — expected: Approximately 5V. Failure: No voltage indicates an open or short in the VCC wire from the PCM.
• Continuity to Ground at Sensor Connector — expected: Below 1 Ω. Failure: High resistance indicates a bad ground connection, which is critical for sensor operation.

Scan Tool Commands That Help

• Honda Diagnostic System (HDS): Clear DTCs — Used at the beginning of diagnosis to reset the system and see if the code returns immediately, which helps differentiate between a hard fault and an intermittent one.
• Honda Diagnostic System (HDS): AT Data List > Input Shaft Speed & Output Shaft Speed — This live data function is used to monitor and compare the speeds of the input and output shafts while driving. For P0722, the Output Shaft Speed will read 0 or be erratic, while the Input Shaft Speed increases, confirming a fault in the output sensor's circuit.

Wiring & Ground Locations

• G101 — On the intake manifold plenum, driver's side of the engine bay. On some models, it is located on the thermostat housing.. G101 is a primary ground termination point for the ECU/PCM and multiple engine sensors. A poor connection at this ground can cause erratic behavior or a complete loss of signal from various sensors, including the transmission speed sensors, potentially triggering a P0722 code even if the sensor and its direct wiring are good.

Real Owner Repair Stories

• YouTube user Willy Garcia (2008 Honda Accord) — Shifting problems and speedometer not working.
  ✅ What actually fixed it The problem was resolved 100% by replacing the output speed sensor with a new part from a Honda dealer.
• YouTube user MODS FOREVER (Honda Accord (model year not specified, but 8th gen body style)) — Blinking 'D' light, speedometer not working, and inability to shift into Park unless the car was turned off first.
  ✅ What actually fixed it Replacing the output speed sensor fixed all symptoms. The speedometer began working correctly and the car could shift into Park while running.
• Honda-Accord-Forum user 'Aaawa' (2008 Honda Accord V6) — Check Engine Light, VSA light, flashing 'D' light, speedometer not working, and car sometimes won't accelerate past 10 mph.
  ❌ Tried (didn't work) Replacing the input and output speed sensors with genuine Honda parts.
  ✅ What actually fixed it The user did not post a final resolution, but a subsequent user with the exact same symptoms reported they had to replace the entire transmission to fix it, indicating a potential internal wiring or component failure beyond the sensor itself in rare cases.

OEM Part Supersession History

• 28820-RWE-003 → 28820-RWE-003 — No supersession found. This part number appears to be the consistent OEM part for the specified vehicle range and other Honda models.
  Heads up: While there is no supersession, it is noted that this sensor (short) is often sold as a set with the input sensor (long, P/N 28810-RZH-004) for other Honda models like the CR-V, but for the Accord P0722, only the 28820-RWE-003 is typically required.

Diagnostic Flowchart

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: A used OEM sensor from a low-mileage donor vehicle is a viable option if on a tight budget, as the failure is electronic and not strictly wear-based. However, given the low cost of new aftermarket parts and the moderate cost of a new OEM part, buying new is generally recommended for peace of mind.

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

What to inspect on the donor part:

• Ensure the donor vehicle was not in a front-end collision that could have damaged the transmission case or wiring.
• Inspect the connector pins on the used sensor for any signs of corrosion, bending, or moisture.
• Check the plastic housing for any cracks or signs of extreme heat exposure.

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

• Output Speed Sensor (highly recommended)

Aftermarket brands forum-validated for this vehicle:

• NTK
• Denso
• Standard Motor Products (SMP)

Brands owners have reported issues with on this vehicle:

• Unbranded, 'white-box' sensors from online marketplaces have a higher reported failure rate or may not resolve the code, as noted in forum discussions.

Real Owner Stories

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

Related OBD-II Codes

• P0721 — Directly related code for the same component. P0721 indicates an erratic or out-of-range signal from the Output Speed Sensor, while P0722 indicates a complete loss of signal. Both point to a faulty sensor or circuit.
• P0717 — Companion speed sensor code. This code indicates 'No Signal' from the Input/Turbine Speed Sensor. It is often grouped with P0722 in diagnostic procedures (as seen in Hyundai TSB 13-AT-014-1) and could indicate a shared wiring harness or PCM issue.
• P0700 — General transmission fault code. This is an informational code set by the PCM to indicate that the Transmission Control Module (TCM) has stored a specific fault, such as P0722. It will almost always be present alongside any transmission-specific code.
• U0101 — Communication code. If there is a wiring issue between the PCM and the transmission, you may see a 'Lost Communication with TCM' code alongside sensor-specific codes like P0722.
• P0746 — Can be triggered by the same underlying fluid issue. Low or dirty transmission fluid, a low-probability cause for P0722, can also cause pressure control solenoid codes like P0746 to appear as metallic debris affects multiple components.

Frequently Asked Questions