OBD-II Code P1722: Transmission Speed Mismatch

What Does P1722 Mean?

P1722 indicates a mismatch between the expected and actual speed of the transmission. The transmission control module (TCM) is receiving conflicting data—for example, the transmission output shaft is spinning at a different rate than the engine or the wheels. This conflict forces the computer into a failsafe mode, causing harsh shifting, stalling, or a dead speedometer.

Technical definition: The definition of P1722 varies by manufacturer. For Nissan, Infiniti, and Subaru, it indicates a 'Vehicle Speed Sensor Signal' or 'Turbine Speed Signal' malfunction, often stemming from the ABS module via the CAN bus. For Ford and Jaguar, it means 'Transmission Stall Speed Failure,' indicating a mismatch between engine and transmission speed when the torque converter should be locked. On BMWs, it points to an internal TCM failure.

Can I Drive With P1722?

Yes, But With Caution. You can drive short distances, but it is unsafe and risks severe damage. The transmission often shifts harshly, locks into a single gear (limp mode), or stalls the engine. Driving with a slipping torque converter overheats the fluid, destroying internal seals and potentially the catalytic converter. Ignoring this code turns a $150 sensor repair into a $2,500+ transmission rebuild.

Common Causes

• Faulty Transmission Speed Sensor (Output or Turbine) (Very Common) — The most frequent cause. These sensors monitor transmission rotational speed. A failed sensor sends erratic data, immediately triggering the code.
🎬 Watch: How to test a transmission speed sensor yourself
• Faulty ABS Wheel Speed Sensor or ABS Module (Common) — On modern vehicles (especially Nissan/Infiniti), the primary vehicle speed signal originates from the ABS module. A single faulty wheel speed sensor sends conflicting data to the TCM, triggering P1722 even if the transmission is flawless.
🎬 See how to easily check your ABS wheel speed sensors
• Damaged Wiring or Corroded Connectors (Common) — Frayed wires, short circuits, or moisture-corroded connectors interrupt the speed sensor signal. Poor ground connections for the TCM or ECU also cause this fault.
• Low or Contaminated Transmission Fluid (Common) — Low fluid causes slipping, overheating, and incorrect operation, leading to stall conditions. Fluid contaminated with metal shavings sticks to magnetic speed sensors, blocking their signal.
• Failed Torque Converter Clutch (TCC) Solenoid (Less Common) — This valve controls torque converter lock-up. A stuck solenoid stalls the engine at stops or fails to lock at highway speeds, which Ford vehicles interpret as a P1722 stall speed fault.
🎬 Watch: How to replace the TCC solenoid on Ford transmissions
• Worn Internal Transmission Components (Less Common) — Wear in the transmission case (like Ford 5R55W/S servo pin bores) causes hydraulic pressure loss. This prevents bands from applying correctly, leading to gear ratio errors. On Jaguars, a failed 'A' drum is a common internal trigger.
• Damaged or Worn Reluctor Ring (Less Common) — Speed sensors read a toothed 'reluctor' ring on a rotating shaft. A cracked ring, broken teeth, or metallic debris produces an erratic signal that the computer flags as a fault.
• Faulty Transmission Control Module (TCM) or PCM (Rare) — The computer itself fails occasionally. On BMWs, P1722 specifically points to an internal TCM error. Rule out all external sensors and wiring before replacing the module.
• Incorrect Tire Size (Rare) — Using non-factory tire sizes (common on Hyundai) alters wheel rotational speeds. This conflicts with the expected transmission output speed, confusing the computer.

Symptoms

• Check Engine Light On — The powertrain control module illuminates the check engine light to indicate a stored fault.
• Harsh or Erratic Shifting — The transmission slams into gear, shifts at incorrect times, or flares between shifts due to missing speed data.
• Transmission Stuck in 'Limp Mode' — The computer forces the transmission into a single gear (typically 3rd or 5th) to prevent internal damage, severely limiting acceleration.
• Inaccurate or Dead Speedometer — The transmission output speed sensor drives the speedometer on most vehicles; a failure kills the gauge.
• Engine Stalling at Stops — If the torque converter fails to unlock when stopping, it drags the engine down and stalls it.
• ABS and Traction Control Lights On — If the fault originates in a wheel speed sensor or the ABS module, the ABS and traction control warning lights illuminate simultaneously.
• Cruise Control Not Working — Cruise control requires a steady vehicle speed signal and disables itself if the signal is erratic or missing.

Diagnostic Flowchart

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

Common Fixes & Costs

• Replace Transmission Speed Sensor (Output/Turbine/Wheel) — Parts: $25 - $150, Labor: $100 - $400, ~1.0 hr book time (DIY)
  Nissan Altima/Maxima: OEM 31935-8E007 (Alt: Beck/Arnley 090-0015, WVE 5S4974)
  Ford Explorer (5R55S/W): OEM XW4Z-7H103-AA (Alt: Dorman 917-617, Standard Motor Products SC214)
• Repair Damaged Wiring or Connectors — Parts: $10 - $50, Labor: $150 - $600, ~2.5 hr book time (Intermediate)
• Transmission Fluid and Filter Change — Parts: $50 - $150, Labor: $100 - $250, ~1.5 hr book time (Intermediate)
• Replace Torque Converter Clutch (TCC) Solenoid — Parts: $50 - $200, Labor: $200 - $500, ~2.5 hr book time (Professional)
  Ford Explorer (5R55S/W): OEM 6L2Z-7G383-A (Alt: Rostra 52-0542, ATP TF-271)
• Replace Transmission Control Module (TCM) — Parts: $400 - $1500, Labor: $150 - $400, ~2.0 hr book time (Professional)

Used vs. New Parts: Buying Guide

When a used part is worth it: Buy new for inexpensive, external speed sensors. For expensive modules like a TCM, a professionally remanufactured unit with a warranty is a smart alternative to a brand new dealer part.

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

Donor quality checklist:

• For electronic parts, a used OEM part is often more reliable than a cheap, unbranded aftermarket part.
• Match the part number exactly; 'equivalent' parts lack the correct electronic properties.
• Ensure a minimum 30-day warranty.

Decision logic:

• If The part is an external sensor and costs < $75 new → Always buy new. The risk of a used part failing isn't worth the $30 savings.
• If The part is internal and requires significant labor to access → Always buy a new OEM or top-tier aftermarket part to avoid paying for labor twice.
• If The part is an expensive electronic module (> $500) → Buy a remanufactured unit from a reputable supplier with a 1-year warranty.

Warranty tradeoff: Used parts offer a 30-90 day functional warranty. New aftermarket parts include a 1-year to limited lifetime warranty. New OEM parts carry a 12-month warranty.

Worst-case if a used part fails: 400-800. This is the cost of paying for labor a second time plus buying a quality part after a cheap used part fails.

What Happens If You Wait — Timeline

1. 0-1 month: Intermittent check engine light or stored code with no light. Minor hesitation or cruise control kicking off. (MPG impact: 0-5%% · Added cost: $0-50 in wasted fuel)
2. 1-3 months: Check Engine Light is on constantly. Shifting becomes noticeably harsher. Speedometer acts up. (MPG impact: 5-10%% · Added cost: $50-150 in wasted fuel)
3. 3-6 months: Transmission frequently enters 'limp mode'. Slipping generates significant heat, darkening the fluid and damaging internal seals. (MPG impact: 10-20%% · Added cost: $800-2000 (Torque converter or solenoid replacement needed))
4. 6+ months: Catastrophic internal failure. Transmission refuses to engage a gear. Burnt fluid and metal shavings destroy clutches and drums. (MPG impact: 20%+% · Added cost: $2500-5000+ (Complete transmission rebuild required))

Cost of Not Fixing It

• 0-1 month: Noticeable drop in fuel economy (5-15%) and increasingly poor shift quality. Annoying but generally not causing immediate component damage. (Added cost: 25-75)
• 1-6 months: Constant slipping generates extreme heat, breaking down transmission fluid. This damages the torque converter and potentially the catalytic converter. (Added cost: 1200-2800)
• 6+ months: Catastrophic internal transmission failure. Burnt fluid and metal debris destroy clutches, seals, and gears, requiring a complete transmission rebuild. (Added cost: 2500-5000)

Diagnosis Steps

1. Scan for All System Codes
   Use an OBD-II scanner to read codes from all modules (Engine, Transmission, ABS). Codes for specific speed sensors (P0715, P0720, P0722), the torque converter (P0741), or CAN communication (U1000) are critical clues. An ABS code (like C1142) is often the root cause of a P1722.
   Tools: Advanced OBD-II Scanner (Beginner)
2. Check Transmission Fluid Level and Condition
   Verify the transmission fluid is at the correct level and is not dark, burnt, or contaminated with metal shavings. Low or dirty fluid causes this code.
   Tools: Rag, Transmission Dipstick (if equipped) (Beginner)
3. Analyze Live Sensor Data
   Graph the vehicle speed readings from the Transmission Output Speed Sensor (OSS) and all four ABS wheel speed sensors simultaneously while driving. A normal OSS value increases steadily with speed. If one sensor drops to zero or spikes erratically, you have found the faulty circuit.
   Tools: Advanced OBD-II Scanner (Intermediate)
4. Visually Inspect Wiring and Connectors
   Inspect the wiring harnesses routing to the transmission speed sensors, ABS wheel speed sensors, and the TCM. Look for chafed wires, loose connections, or green corrosion on the pins. Verify module ground connections are tight and clean.
   Tools: Flashlight (Beginner)
5. Test Sensor Circuit Voltage and Ground (3-wire Hall-Effect)
   Unplug the 3-wire sensor and turn the key to 'ON' (engine off). Use a multimeter to test the connector. You must find a 5V or 12V reference wire and a ground wire with less than 0.5Ω resistance to the chassis. If either is missing, repair the wiring harness.
   Tools: Multimeter, Repair Manual, Back-probe kit (Advanced)
6. Test Sensor Resistance (2-wire Magnetic Pickup)
   Unplug the 2-wire sensor and measure the resistance (Ohms) between its two pins. Compare this to the factory specification (typically 600-1500 Ohms). An open circuit (OL) or zero resistance confirms a dead sensor.
   Tools: Multimeter, Repair Manual (Intermediate)
7. Check for AC Voltage Signal (2-wire sensors)
   With the 2-wire sensor unplugged, set the multimeter to AC Volts across the sensor pins. Spin the corresponding wheel or shaft. The sensor must generate a small AC voltage (>100mV) that increases with speed. No voltage means a bad sensor or damaged reluctor ring.
   Tools: Multimeter, Jack and Jack Stands (Advanced)
8. Analyze Sensor Waveform with an Oscilloscope
   Back-probe the sensor's signal wire with an oscilloscope. A magnetic sensor produces a clean AC sine wave; a Hall-effect sensor produces a 0V-to-5V DC square wave. Dropouts or noise indicate a failing sensor, wiring fault, or cracked reluctor ring.
   Tools: Oscilloscope, Back-probe kit (Professional)
9. Test TCC Solenoid Resistance
   If diagnosing a stall speed failure (common on Ford), test the Torque Converter Clutch solenoid. Unplug the solenoid and measure its resistance. For a Ford 5R55S, it must measure 0.98 to 1.62 Ohms. Out-of-spec readings require replacement.
   Tools: Multimeter, Repair Manual (Advanced)
10. Inspect the Torque Converter Clutch (TCC) Solenoid
    Remove the transmission oil pan to visually inspect the TCC solenoid and its internal wiring harness for damage or heavy metallic sludge contamination.
    Tools: Socket Set, Drain Pan, New Gasket, Transmission Fluid (Advanced)

When This Code Triggers (Freeze-Frame Conditions)

• Engine Coolant Temp: 180-205°F (Logged when the engine and transmission are fully warmed up and have exited cold-start enrichment.)
• Engine RPM: 1500-2500 RPM (Occurs during steady-state cruising or light acceleration, rarely during heavy throttle.)
• Engine Load: 25-60% (Sets under moderate, consistent engine load where the TCM expects a predictable speed ratio.)
• Vehicle Speed: 35-60 mph (Triggered at highway speeds when the torque converter clutch commands lock-up.)

Related Codes

• P0720 / P0722 — These point specifically to a fault in the Output Speed Sensor (OSS) circuit. If you have P1722 alongside P0720/P0722, the OSS or its wiring is the root cause.
• P0715 — Points to a fault with the Input/Turbine Speed Sensor (ISS). If the ISS fails, the TCM cannot verify the gear ratio and sets P1722 due to conflicting data.
• P0500 — A generic fault for the Vehicle Speed Sensor (VSS). A failing VSS causes the speed mismatch that triggers P1722, so these codes frequently appear together.
• P0741 — Indicates the Torque Converter Clutch (TCC) is stuck off. P1722 ('Stall Speed Failure') is the resulting symptom, as the failure to lock up causes a speed difference between the engine and transmission.
• U1000 — A CAN bus communication error. On Nissan and Infiniti, the speed signal travels from the ABS module to the TCM over this network. A U1000 code alongside P1722 strongly suggests a communication breakdown, not a failed sensor.

Climate & Environmental Factors

• Road Salt (Winter Climates): Saltwater acts as an electrolyte, accelerating the decay of copper wires and connector pins. This causes intermittent signal loss and is a primary cause of wiring-related P1722 codes in the 'rust belt'.
• High Humidity: Sustained humidity promotes moisture intrusion into aging electrical connectors, leading to corrosion that disrupts sensitive voltage signals from speed sensors.
• Extreme Heat: Prolonged high engine bay temperatures make plastic wire insulation brittle and accelerate the breakdown of electronic components inside the speed sensor.

How to Talk to a Mechanic About This Code

Say this: "I have a P1722 transmission code. Please check for any ABS or communication codes (U-codes) and graph the live data from the wheel speed sensors and transmission output sensor before recommending a repair. I want to rule out a wiring or ABS sensor issue first."

This proves you know P1722 is frequently caused by faults outside the transmission. It forces the technician to perform a logical electrical diagnosis rather than immediately quoting a $3,000 transmission rebuild.

Avoid saying:

• 'My transmission is slipping, just fix it.'
• 'My check engine light is on, can you look at it?'
• 'Just replace the speed sensor.'

Questions to ask before authorizing the repair:

• Did you find any other codes in the ABS, engine, or communication modules?
• Were you able to graph the live speed sensor data? Did one sensor drop out?
• If replacing a sensor, did you test the wiring connector for 5V power and ground first?
• What is the warranty on this specific repair, including parts and labor?

Where to Take It: Dealer vs Independent vs Chain

• Dealer: Recommended for Nissan/Infiniti due to CVT warranty extensions and complex CAN/ABS integration. Strong choice if a software or control module problem is suspected.
  Best for: Vehicles under warranty (especially Nissan/Infiniti with CVT warranty extensions)., Complex CAN bus communication faults or required software updates., Newer German vehicles (BMW, Mercedes) where P1722 points to proprietary module failures.
  Downsides: Highest labor rates., Quick to recommend replacing a major assembly (full CVT or valve body) instead of a component-level repair. (Typical cost: +50% vs. baseline)
• Independent Shop: The best fit for most owners. Independent transmission specialists offer the best balance of expertise and value for diagnosing speed mismatch codes.
  Best for: Out-of-warranty vehicles with well-documented issues (e.g., Ford TCC solenoid)., Diagnosing and repairing common sensor and wiring faults., Component-level repairs (replacing an internal sensor instead of the whole valve body).
  Downsides: Diagnostic capabilities vary; ensure the shop has advanced scanners and transmission experience. (Typical cost: +0% vs. baseline)
• Chain Shop: Avoid for initial diagnosis. Acceptable only if a proper diagnosis has already confirmed a simple external part is the cause.
  Best for: Simple, clear-cut fixes like a fluid change or an easily accessible external speed sensor replacement.
  Downsides: Technicians lack the advanced diagnostic tools and specific knowledge for complex P1722 causes., Unable to diagnose CAN bus or internal transmission faults. (Typical cost: -10% vs. baseline)

When to Walk Away From the Repair

If the estimated repair cost exceeds 40-50% of the car's private-party value, sell or trade in the vehicle. Lower this threshold to 40% for older, high-mileage cars.

• Car worth $8000, fix is $700: Fix it. A $700 repair for a TCC solenoid is well below the 40-50% threshold.
• Car worth $4000, fix is $3500: Walk away. A full transmission rebuild (87.5% of the car's value) is a poor investment.
• Car worth $5000, fix is $2200: Borderline. At 44% of the car's value, the decision depends on overall condition. If it needs tires or brakes soon, walk away. If it is pristine, repair it.

What Scan Tool You Need for This Code

Minimum: A scanner that reads and clears enhanced, manufacturer-specific codes from the Transmission Control Module (TCM) and Anti-lock Brake System (ABS), and supports live data streaming.

A basic $20 code reader only shows the P1722 code from the engine computer. It cannot access the TCM or ABS modules, where the root cause (like a faulty wheel speed sensor) lies. Without live data, you cannot compare sensor readings, leading to guesswork.

Budget: BlueDriver Pro Scan Tool (~$99) — Connects to a smartphone app to read/clear enhanced ABS and TCM codes. Graphs live data from multiple sensors simultaneously, essential for comparing wheel speed and transmission output speed signals.

Mid-range: Foxwell NT510 Elite (~$150) — A handheld device offering broad vehicle compatibility for ABS and TCM codes. Offers bidirectional controls to test components like solenoids without turning wrenches.

Professional: Autel MaxiCOM MK808S (~$450) — A professional tablet scanner providing full-system diagnostics. Offers robust live data graphing, bidirectional controls, and performs service functions like resetting transmission adaptation values after a repair.

Rent vs buy: For a one-time diagnosis, use AutoZone's Loan-A-Tool program to rent a capable scanner for free. If you perform maintenance yearly, buying the BlueDriver is cost-effective.

How to Clear the Code After You Fix It

1. Use an OBD-II scan tool to clear all diagnostic trouble codes.
2. Perform a complete transmission drive cycle to allow the system to relearn.
3. Rescan the vehicle to ensure the P1722 code does not return.

Drive cycle (~20 minutes): Start the engine cold and idle for 3 minutes. Drive in stop-and-go traffic for 10 minutes, including several accelerations and decelerations. Drive at a steady highway speed (55-60 mph) for 10 minutes. Let the vehicle cool down completely.

Readiness monitors affected: Comprehensive Component Monitor, Catalyst Monitor, Oxygen Sensor Monitor

Watch out for:

• Clearing the code without fixing the underlying issue guarantees the code will return.
• Disconnecting the battery clears the code but resets all readiness monitors, causing an automatic emissions test failure.
• Failing to perform a long enough drive cycle leaves monitors 'Incomplete' for state inspections.

Will This Fail Emissions / State Inspection?

Yes — this code typically fails an OBD-II emissions inspection.

• California: An illuminated Check Engine Light from P1722 is an automatic failure of the smog check's OBD-II inspection.
• New York: The NYS DMV emissions inspection includes an OBD-II scan. An active P1722 code results in an automatic failure.
• Texas: In the 17 Texas counties requiring emissions testing, a vehicle with an illuminated Check Engine Light automatically fails.

Most Commonly Affected Vehicles

• Nissan Altima, Maxima, Murano, Cube (2004-2018) — Frequently caused by a failed vehicle speed sensor (VSS) on the CVT. However, it is commonly triggered by a fault in the ABS system or CAN bus. Always check for U1000 or C-codes before replacing transmission parts.
• Ford Explorer, Ranger, Mustang (2002-2010) — Associated with 5R55W/S/E transmissions. The code points to a failing TCC solenoid or worn servo bores inside the transmission case causing pressure loss (TSB 09-12-12).
• Subaru Legacy, Outback, Impreza (2005-2014) — Relates to the Turbine 2 Speed Sensor or an 'Auto Trans Diagnosis Input Signal High' fault. Often caused by poor ECU/TCM ground connections or internal valve body issues.
• Jaguar XK8, XJ8 (1997-2002) — Defined as 'Stall Speed Failure'. Frequently a sign of impending or current failure of the 'A' drum within the ZF 5HP24 transmission, requiring a full rebuild.
• Chevrolet Silverado 1500 (2014-2021) — Caused by a failed output speed sensor located inside the transmission attached to the valve body, making it a labor-intensive $600+ repair.
• BMW 3-Series, 5-Series (2000-2015) — Defined as 'TCM - internal error', pointing directly to a failure of the Mechatronic control unit. A weak battery also triggers this code.
• Hyundai Elantra, Sonata, Santa Fe (2010-2018) — Caused by a faulty speed sensor, using mismatched tire sizes, or outdated TCM software requiring a dealer update.
• Infiniti G35, FX35 (2003-2008) — Linked to the CAN communication network. A fault in the ABS system (C1130) interrupts the speed signal to the TCM, causing P1722 even with a healthy transmission.

Manufacturer-Specific Notes

• Nissan/Infiniti: The primary vehicle speed signal is sent from the ABS module to the TCM via the CAN bus. A problem in the ABS system (like a wheel speed sensor) triggers P1722 even if the transmission is fine. Always check for ABS and U-series codes (TSB NTB10-066).
• Ford: The 'Stall Speed Failure' on 5R55S/W/N transmissions is often caused by worn servo pin bores in the aluminum transmission case, leading to hydraulic pressure loss (TSB 09-12-12). This requires specialized tools to install sleeves in the bores.
• Subaru: Often relates to the 'Turbine Speed Sensor 2' or an 'Auto Trans Diagnosis Input Signal High' fault caused by poor electrical grounds for the ECU or TCU. The turbine speed sensor is internal to the valve body and not sold separately by dealers.
• Jaguar: Frequently a sign of impending failure of the 'A' drum within the ZF 5HP24 transmission. Symptoms include a clunk when engaging drive and a no-move condition followed by limp mode, requiring a rebuild.

Real Owner Stories

2009 Nissan Cube with CVT at 61K miles

Code P1722 appeared on a scanner, but the Check Engine Light was off and there were no driving symptoms.

What they tried:

1. Cleared the code, but it reappeared intermittently.

Outcome: A known fix for this model is repairing the TCM wiring harness. Since there were no symptoms, the owner monitored the situation to address at the next service.

Lesson: A P1722 code logged without a check engine light or symptoms often points to an intermittent wiring or communication issue rather than a hard sensor failure.

1998 Jaguar XJ8 at 70K miles

After a car wash, the car went into limp mode with a 'Gearbox Fault' message and code P1722.

What they tried:

1. A dealership quoted $6,500 for a new transmission without further diagnosis.

Outcome: The owner suspected water intrusion from the car wash. The actual cause was a water-damaged electrical connector, not a catastrophic transmission failure.

Lesson: Be wary of shops condemning the entire transmission based solely on a code. Sudden failure after exposure to water strongly suggests a cheap electrical connector fix.

1999 Jaguar XK8 at 113K miles

Car displayed 'Transmission Fault', went into limp mode, and threw code P1722.

What they tried:

1. Towed to a transmission shop for diagnosis.

Outcome: The shop diagnosed a failed 'B' drum, a known failure point on the ZF 5HP24 transmission. The repair required a full transmission rebuild.

Lesson: On Jaguar models, P1722 is a classic sign of an impending 'A' or 'B' drum failure. A sudden clunk followed by limp mode means internal mechanical failure, requiring a specialist.

2012 Subaru Outback 3.6R with 5EAT

Intermittent hard 1-2 shifts with a flashing 'AT OIL TEMP' light. Scanner found a P1710/P1722 code related to the turbine speed sensor.

What they tried:

1. Confirmed fluid level was correct.

Outcome: The internal Turbine Speed Sensor 2 failed. Subaru only sells the entire $1,800 valve body, so the owner sourced an aftermarket sensor online and had a mechanic splice it in.

Lesson: For internal sensors, the manufacturer may not sell the part individually. Research aftermarket sensor solutions to avoid a costly full valve body replacement.

How to Prevent This Code From Triggering

• Change transmission fluid and filter at recommended intervals. (Every 30,000 to 60,000 miles for most vehicles.) — Clean fluid lubricates parts, prevents overheating, and removes contaminants that clog solenoids or damage sensors.
• Apply dielectric grease to electrical connectors. (Whenever a sensor or connector is serviced.) — Dielectric grease blocks moisture and oxygen from reaching metal pins, preventing corrosion that causes sensor signal failure.
• Regularly wash the vehicle's undercarriage. (Frequently during winter in 'rust belt' areas.) — Washing away road salt prevents it from corroding wiring harnesses and ground straps, common failure points for electrical codes.
• Avoid aggressive driving and heavy towing. (Daily habit.) — Harsh acceleration creates excessive heat, which breaks down fluid, hardens seals, and damages electronic components.
• Check for fluid leaks during routine oil changes. (Every 5,000-7,500 miles.) — Catching small leaks early prevents the fluid level from dropping low enough to cause slipping and internal damage.

Frequently Asked Questions

What are the most common mistakes when diagnosing P1722?

The biggest mistake is replacing a transmission speed sensor without testing its circuit first. A frayed wire or corroded connector mimics a failed sensor. On Nissans and Infinitis, failing to check the ABS system for faults is another common error, as a bad wheel speed sensor signal often causes the TCM to report P1722.

What is a 'reluctor ring' and how can it cause P1722?

A reluctor ring is a toothed metal wheel that spins past the speed sensor. The sensor counts these teeth to measure rotational speed. If the ring cracks or collects metallic debris, the sensor reads an erratic signal, triggering P1722.

What does 'stall speed failure' mean?

It means the computer detected a mismatch between engine RPM and transmission input RPM. This usually occurs when the torque converter fails to lock up correctly at cruising speed. The resulting 'slip' is interpreted by the computer as a stall.

Can I just clear the P1722 code?

You can clear the code with a scanner, but it will return until the underlying mechanical or electrical problem is fixed. Ignoring it causes worsening shift quality and potentially severe, expensive transmission damage.

How much does it cost to fix P1722?

An external speed sensor replacement costs between $125 and $400. If the sensor is inside the transmission, labor increases the cost to $400-$600+. A faulty TCC solenoid costs $250-$700, while major internal repairs like a Jaguar 'A' drum failure exceed $3,000.

Can a weak battery cause a P1722 code?

Yes, a weak or failing battery causes low voltage issues in modern electronically controlled transmissions. This leads to communication errors between modules. These voltage drops trigger a variety of fault codes, including P1722.

Why did my speedometer stop working when I got code P1722?

The transmission's output speed sensor provides the signal for the speedometer on most vehicles. When this sensor or its wiring fails, it triggers the P1722 code. Simultaneously, the loss of this signal causes the speedometer to die or behave erratically.

What kind of transmission fluid should I use?

Always use the specific Automatic Transmission Fluid (ATF) recommended by your vehicle's manufacturer. Using the wrong fluid causes shifting problems, overheating, and triggers fault codes. Check your owner's manual for the exact specification, such as Mercon V or Nissan NS-3.

Key Takeaways

• Scan all vehicle modules—including the ABS and TCM—because a single $50 faulty wheel speed sensor frequently triggers P1722 on Nissan and Infiniti models.
• Graph live data from the transmission output speed sensor and all four wheel speed sensors simultaneously to pinpoint the exact circuit causing the speed mismatch.
• Never replace a transmission speed sensor without first testing its 3-wire connector for a steady 5V reference and a solid ground with a multimeter.
• Stop driving immediately if the transmission enters 3rd-gear limp mode, as continuing to drive overheats the fluid and turns a minor repair into a $3,000 rebuild.