P0222 on 2011-2013 Mazda CX-9: Throttle Position Sensor Causes and Fixes

What's Unique About the 2011-2013 Mazda CX-9

P0222 on this specific CX-9 is a well-documented issue with two very common causes, both addressed by Mazda Technical Service Bulletins (TSBs). Unlike a generic P0222 which could have many causes, the problem on this vehicle is almost always either electrical noise in the engine harness or a complete failure of the electronic throttle body. The throttle position sensors are integrated into the throttle body and are not sold separately, so diagnosis often leads to replacing the entire assembly. This issue is also common on its platform mates, the Ford Edge and Lincoln MKX, which use the same Ford Cyclone 3.7L engine.

Symptoms You May Notice

• Check Engine Light is on
• Wrench warning light may be illuminated
• Vehicle enters limp mode (reduced engine power)
🎬 Watch: Mazda limp mode and power drop explained
• Sluggish, jerky, or hesitant acceleration
• Unresponsive throttle pedal
• Rough idle
• Difficulty starting the engine
• Engine may stall

Most Likely Causes

1. Electrical Noise in Engine Harness 🔴 High Probability Mazda identified this as a specific issue and released TSB #01-008/13 to address it. Abnormal electrical noise can cause the PCM to misread sensor data, triggering P0222 and/or P0123.
   How to confirm: This is difficult to confirm without trying the fix. It is often diagnosed when P0222 appears along with P0123. The TSB is the primary diagnostic indicator. If the codes appear immediately at startup, this is a strong indicator.
   Typical fix: Install a specific throttle body sub-harness with a built-in diode (Part No. AJT1-13-ZS8) as per TSB #01-008/13.
   Est. part cost: $50-$100
2. Failed Electronic Throttle Body Assembly 🔴 High Probability → Shop Fuel Injection Throttle Body The internal throttle position sensors (TPS) are a common failure point due to contamination or wear of internal contacts. Since they are integrated into the throttle body, the entire unit must be replaced. This is a known issue shared with Ford platform mates.
   How to confirm: After ruling out wiring issues (including the TSB harness fix), test the sensor circuits at the throttle body connector for correct voltage and resistance. If the harness and PCM are good, the throttle body is the likely culprit. 🎬 Watch: How to test and replace the electronic throttle body A stuck low voltage reading on TP Sensor No. 2 (Pin C) that doesn't change with pedal input confirms failure.
   Typical fix: Replace the entire electronic throttle body assembly. A throttle body relearn procedure (KAM reset) is required after installation.
   Est. part cost: $250-$500
3. Damaged Wiring or Poor Connection 🟡 Medium Probability
   How to confirm: Visually inspect the wiring harness and connectors between the PCM and the throttle body for any signs of damage, corrosion, or loose pins. Check for a short to ground on the signal wire (Pin C at the throttle body connector) or an open in the ground wire (Pin E).
   Typical fix: Repair or replace the damaged section of the wiring harness or clean/repair the connector.
   Est. part cost: $10-$150

Rare But Worth Checking

• Powertrain Control Module (PCM) Failure: → Shop Engine Control Module (ECM) This is the least likely cause. The PCM should only be suspected after all other possibilities, including the throttle body and all related wiring, have been thoroughly tested and ruled out. A common cause of PCM failure on this platform is a bad ignition coil, which may present with codes like P0351-P0356.

Diagnosis Steps

1. Check for any Technical Service Bulletins (TSBs) related to P0222 for this vehicle. TSB #01-008/13 is highly relevant.
2. Scan for other codes. Note if P0123 is also present, as this strongly points to the TSB fix.
3. Visually inspect the wiring harness and connector at the electronic throttle body for any obvious damage, corrosion, or loose connections.
4. If TSB #01-008/13 has not been performed, install the diode harness kit (AJT1-13-ZS8) as this is a known fix and a relatively inexpensive first step.
5. If the code returns, test the circuits at the throttle body connector. Check for a short to ground on the TP Sensor No. 2 signal wire (Pin C) and check for a good ground connection on Pin E.
6. If wiring and connections are confirmed to be good, the failure is most likely within the throttle body assembly itself.
7. Replace the electronic throttle body assembly (OEM Part No. TK21-13-640).
🎬 See this step-by-step CX-9 throttle body replacement walkthrough
8. After replacement, perform a Keep Alive Memory (KAM) reset by disconnecting the negative battery terminal for at least 15 minutes. Then, perform an idle relearn procedure by starting the engine and letting it idle for 10-15 minutes to reach operating temperature.

Parts You'll Likely Need

• Throttle Body Harness/Diode Kit (OEM #AJT1-13-ZS8) — This is a specific part released by Mazda to fix a known electrical noise issue that causes codes P0222 and P0123.
  Trusted brands: Mazda (OEM)
  OEM price range: $50-$100
  Aftermarket price range: N/A
• Electronic Throttle Body Assembly (OEM #TK21-13-640) — The throttle position sensors are integrated into the throttle body. If the sensor fails, the entire assembly must be replaced. This is the most common fix if the diode harness does not resolve the issue.
  Trusted brands: Mazda (OEM), Hitachi, Bosch
  OEM price range: $350-$550
  Aftermarket price range: $250-$400

Related Codes That Often Appear With This One

• P0123 — P0123 (Throttle Position Sensor No.1 Circuit High Input) often appears with P0222. Mazda's TSB #01-008/13 specifically mentions these two codes appearing together as an indicator of the electrical noise issue.

Technical Service Bulletins (TSBs) & Recalls

• 01-008/13 - 'MIL ON WITH DTCS P0123 AND/OR P0222'. Describes a fix for electrical noise by installing a throttle body harness/diode kit (Part No. AJT1-13-ZS8).
• 01-012-15 - 'LACK OF POWER WITH DTC P0123 / P0222'. Points to a throttle position sensor fault, reinforcing that throttle body replacement is a common fix.
• 01-015/13 - 'MIL ILLUMINATION WITH DTC P2135 OR DTCS P0123 AND/OR P0222 AFTER THROTTLE BODY REPLACEMENT'. Clarifies that the diode harness may be required even *after* a new throttle body is installed if the codes reappear.
• TSB Bulletin #01-008-13-2771 - Notes that some vehicles may experience MIL illumination with DTC P0123 (Throttle Position Sensor No.1 Circuit High Input) and/or DTC P0222 (Throttle Position Sensor No.2 Circuit Low Input) stored in memory.
• TSB Bulletin #01-012-15-3052 - Reports that vehicles may experience a lack of power and the wrench light (Powertrain Malfunction / Reduced Power Warning Light) comes on with DTCs P0123 and P0222 stored in memory.

Platform-Specific Known Issues

• A known issue of abnormal electrical noise within the engine harness can trigger P0222, often accompanied by P0123. Mazda addressed this with TSB #01-008/13, which involves installing a sub-harness with a diode.
• Another TSB, #01-012-15, also notes lack of power with DTCs P0123 and P0222, pointing towards a throttle position sensor fault requiring throttle body replacement.

Mechanic-Grade Diagnostic Values

• TP Sensor No. 2 (TPS 'B') Voltage - Code Trigger — expected: Approx. 0.5V (closed) to 4.5V (wide open). Failure: Voltage is detected below 0.2V for more than 0.5 seconds.
• TP Sensor No. 1 (TPS 'A') Voltage - P0123 Trigger — expected: Approx. 0.5V (closed) to 4.5V (wide open). Failure: Voltage is detected above 4.85V - 4.9V while the engine is running.
• Continuity Check - Throttle Body to PCM — expected: Near 0 ohms of resistance between corresponding pins.. Failure: Infinite resistance (OL) indicates an open circuit. Continuity to ground or power on a signal line indicates a short.

Scan Tool Commands That Help

• Mazda IDS (or equivalent professional scanner like Autel, Snap-on): Throttle Actuator Test (Bidirectional Control) — This command allows the technician to directly order the throttle plate to open and close while monitoring sensor PIDs (TP1, TP2). If the plate fails to move as commanded or the sensor voltages don't respond correctly, it confirms a failure in the throttle body assembly.
• Mazda IDS (or equivalent): PID Data Monitoring (TP1, TP2) — Use this to watch the live voltage output of both throttle position sensors simultaneously while operating the pedal. This can reveal glitches, erratic jumps, or a sensor that is not responding, which points to an internal throttle body fault.

Wiring & Ground Locations

• 0140-222 — The main 6-pin electrical harness connector that plugs directly into the electronic throttle body assembly on the top rear of the engine.. This is the primary connection point for all throttle body circuits. TSB #01-008/13 involves modifying this connector by installing a new pigtail with a diode. A poor connection here can cause P0222.
• Throttle Body Connector Pin C — Pin 'C' on the 6-pin connector 0140-222.. This is the signal wire for TP Sensor No. 2. A short to ground on this wire will cause a P0222 code. This wire runs to PCM terminal 2AL.
• Throttle Body Connector Pin E — Pin 'E' on the 6-pin connector 0140-222.. This is the sensor ground wire. An open circuit (broken wire) on this line will cause a P0222 code. This wire runs to PCM terminal 2Z.
• PCM — Located in the left rear corner of the engine compartment, near the battery tray.. This is where all sensor signals are processed. Testing for continuity between the throttle body connector and the PCM connector pins (e.g., Pin C to 2AL, Pin E to 2Z) can definitively rule out a wiring harness issue.

OEM Part Supersession History

• ca0113640, ca0113640a, ca0113640b, zzj113650a → TK21-13-640 — Part number consolidation and potential design revisions over the vehicle's life.
  Heads up: While multiple part numbers exist, TK21-13-640 is the most current OEM replacement number for this application.

Diagnostic Flowchart

Other Known Issues on This Vehicle

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

• Internal Water Pump Failure 🔴 High — A well-known and feared issue. Failure can occur without warning, often between 60,000 and 120,000 miles. Because the pump is chain-driven and internal, its failure allows coolant to mix with engine oil, leading to catastrophic engine damage. (Ref: No recall, but subject of class-action lawsuits.)
• AWD Transfer Case (PTU) Failure 🔴 High — Common on AWD models. The small fluid capacity and high heat can cause the fluid to break down, leading to overheating and internal failure of the Power Transfer Unit. Symptoms include a burning oil smell and grinding noises. (Ref: Mazda issued a Special Service Program (SSP 92) extending the warranty to 7 years/90,000 miles for this issue on 2010-2014 models.)
• Power Brake Booster Failure 🟠 Medium — Owners report a hard brake pedal and a hissing noise from the driver's footwell, indicating a loss of power assist. This is caused by the internal diaphragm deteriorating, especially in high-heat climates. (Ref: NHTSA investigated, and Mazda responded with a Special Service Program (SSP 93) extending the warranty on the brake booster to 7 years/90,000 miles for 2007-2013 models.)
• Front Lower Control Arm Corrosion 🔴 High — In salt-belt regions, water can enter the front suspension ball joints, causing corrosion and potential separation of the lower control arm, which would result in a loss of steering. (Ref: Mazda Recall 8515G)

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: A used OEM throttle body from a reputable salvage yard can be a cost-effective option, as this part is a common failure and readily available. Given the high cost of a new OEM unit, a used part can save significant money.

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

What to inspect on the donor part:

• Verify the donor vehicle's mileage; lower is always better.
• Inspect the electrical connector pins for any signs of corrosion, bending, or damage.
• Look at the throttle plate and bore; excessive carbon buildup may suggest a hard life, but it can be cleaned.
• Ensure the part comes with a short warranty (e.g., 30-90 days) from the salvage yard in case it's dead on arrival.

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

• Throttle Body Harness/Diode Kit (AJT1-13-ZS8) - This is a Mazda-specific solution and no aftermarket equivalent exists.

Aftermarket brands forum-validated for this vehicle:

• Hitachi (Often the original equipment manufacturer)
• Bosch

Brands owners have reported issues with on this vehicle:

• Unbranded, no-name units from online marketplaces should be avoided, as their internal electronics may not meet OEM specifications for sensor accuracy and durability, leading to a quick return of the problem.

Real Owner Stories

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

Related OBD-II Codes

• P0123 — Often appears simultaneously with P0222 on this vehicle due to electrical noise in the engine harness, as addressed in TSB #01-008/13.
• P2135 — A throttle position sensor voltage correlation code that may appear alongside or after P0222, indicating the need for the diode harness kit.
• P2100 — Related to throttle actuator control circuit issues, often cited in forum reports alongside P0222 when the throttle body assembly fails.
• P0122 — A low-input companion code for the throttle position sensor, frequently seen on platform mates like the Lincoln MKX sharing the same 3.7L engine.

Frequently Asked Questions