P0222 on 2007-2009 Saturn Aura 3.6L: Throttle Position Sensor 'B' Circuit Low Causes and Fixes

What's Unique About the 2007-2009 Saturn Aura

The electronic throttle body on this generation of Saturn Aura (and other GM vehicles using the 3.6L LY7 engine) is a well-documented failure point. The internal sensors, which use carbon tracks, wear out over time, causing the signal voltage to drop and trigger the P0222 code. The issue was so widespread that General Motors issued a Special Coverage Adjustment (No. 11273), extending the warranty on the throttle body to 10 years or 120,000 miles. While this warranty has expired due to the vehicle's age, it confirms that a P0222 code on this specific car points very strongly to a defective throttle body assembly itself. Cleaning the throttle body is unlikely to be a permanent fix, as the problem is electronic, not just carbon buildup.

Symptoms You May Notice

• "Reduced Engine Power" me 🎬 See why this common GM defect causes limp modessage on the dashboard
• "Service ESC" message may also appear
• Check Engine Light is on
• Poor or hesitant acceleration
• Vehicle feels sluggish or won't accelerate properly
• Unstable or rough idle
• Engine may stall

Most Likely Causes

1. Faulty Electronic Throttle Body Assembly 🔴 High Probability This is a known factory defect acknowledged by GM through a special extended warranty program (No. 11273). The internal throttle position sensors use carbon tracks that wear out or develop dead spots, causing irrational voltage signals.
   How to confirm: Because the sensors are internal to the throttle body, direct testing is difficult. Given the high failure rate on this platform, if the wiring harness and connector are confirmed to be in good condition (no damage, corrosion, or loose pins), the throttle body is the presumed cause. Cleaning the unit rarely solves a P0222 code, as the fault is electronic.
   Typical fix: Replace the entire throttle body assembly. The sensors are not available as separate parts. A throttle relearn procedure must be performed after replacement.
   Est. part cost: $150 - $350
2. Damaged Wiring or Connector 🟡 Medium Probability Harnesses can become brittle with age and engine heat cycles. The connector lock can become brittle and fail, leading to a poor connection.
   How to confirm: Visually inspect the wiring harness and connector going to the throttle body for any signs of damage, corrosion, or loose pins. Perform a 'wiggle test' on the harness with the engine running to see if it causes the idle to change or the code to appear. Use a multimeter to check for a stable 5-volt reference and good ground at the connector.
   Typical fix: Repair the damaged section of wire or replace the connector pigtail.
   Est. part cost: $15 - $50

Rare But Worth Checking

• Faulty Engine Control Module (ECM): This is very rare. The ECM should only be considered after definitively ruling out the throttle body and all related wiring. The 3.6L LY7 engine's ECM shares a 5-volt reference circuit across multiple sensors, so an ECM issue could potentially manifest as a low voltage code, but it is highly unlikely to be the root cause for an isolated P0222.

Diagnosis Steps

1. Scan for Codes: Use an OBD-II scanner to confirm P0222 and check for any other related codes like P0122 or P2135. The presence of P2135 is a very strong indicator of throttle body failure.
2. Inspect the Throttle Body Connector: Disconnect the electrical connector at the throttle body. Check for corrosion, bent or backed-out pins, and moisture. Ensure the locking tab engages securely.
3. Check the Wiring: Inspect the wiring harness leading to the throttle body for any signs of chafing, melting, or physical damage. Pay close attention to where the harness may rub against other components or the engine block.
4. Test for Power and Ground (Optional): Using a multimeter and a wiring diagram, you can back-probe the connector to verify a stable 5-volt reference signal and a solid ground connection from the ECM. A low voltage reading on the signal wire confirms the fault condition.
5. Replace the Throttle Body: If the wiring and connector are intact, the next step is to replace the throttle body assembly. 🎬 Watch: How to test and replace the throttle body This is the most common and accepted fix for this code on the Saturn Aura.
6. Perform Throttle Relearn Procedure: After installing the new throttle body, a relearn procedure is critical. A consolidated manual procedure is as follows: a. Turn the ignition to ON (engine off) for 2-3 minutes. You may hear the new throttle body buzz or click as it calibrates its end points. Turn ignition OFF for 60 seconds. b. Start the engine and let it idle in Park for 3 minutes. The idle may be high or unstable initially. c. Turn the engine OFF for 60 seconds. d. Restart the engine and let it idle in Park for another 3 minutes. The idle should now be settling closer to normal. 🎬 Watch: A visual guide to the GM relearn procedure e. Drive the vehicle for 5-10 minutes, including some stop-and-go and steady cruising, to allow the ECM to fine-tune the idle and off-idle throttle response.

Parts You'll Likely Need

• Electronic Throttle Body Assembly (OEM #12615503) — This is the most common failure item for code P0222 on this vehicle, confirmed by GM Special Coverage program 11273. The internal sensors are not sold separately. This part number supersedes older numbers 12595829 and 12618735.
  Trusted brands: ACDelco (GM Genuine), Dorman (OE FIX), Spectra Premium, Hitachi, SKP
  OEM price range: $250-$400
  Aftermarket price range: $150-$275
• Throttle Body Gasket (OEM #Felpro 61520 or ACDelco 40-5083) — A new gasket is required to ensure a proper seal when replacing the throttle body. Most new throttle bodies include one, but it's wise to confirm.
  Trusted brands: ACDelco, Fel-Pro, Mahle
  OEM price range: $10-$20
  Aftermarket price range: $5-$15

Related Codes That Often Appear With This One

• P2135 — This code indicates a 'Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation' error. It means the ECM is seeing signals from the two internal sensors that don't match. This is a direct consequence of the 'B' sensor failing and sending a low voltage signal (P0222) while the 'A' sensor reports a normal voltage, creating a conflict.
• P0122 — This is the corresponding 'low voltage' code for the 'A' sensor circuit. If both P0122 and P0222 appear, it strongly suggests a problem with the throttle body connector, its wiring, or a shared ground/power supply, rather than just one internal sensor failing.

Technical Service Bulletins (TSBs) & Recalls

• Special Coverage Adjustment No. 11273 / 11273A: Extended warranty coverage for the throttle position sensor (requiring throttle body replacement) to 10 years/120,000 miles due to high failure rates causing rough running and 'Reduced Engine Power' mode.
• Related TSB for Platform Mate: Special Coverage Adjustment No. 14582A was issued for the same issue on the Pontiac G6, further confirming the defect across vehicles with this powertrain.

Platform-Specific Known Issues

• GM Special Coverage Adjustment No. 11273 was issued for failing throttle position sensors within the throttle body, causing 'Reduced Engine Power' mode. This confirms it as a widespread factory defect.
• Owner Experience: A user on SaturnFans.com with a 2008 Aura XR experienced a high idle (P0507) after a mechanic cleaned the throttle body. Another user advised that the idle relearn process is automatic and can be heard calibrating with the key in the 'ON' position, confirming that replacement, not cleaning, is the standard fix for electronic faults like P0222.

Mechanic-Grade Diagnostic Values

• TPS 'B' Signal Voltage (Key On, Engine Off) — expected: Approx. 0.5V at closed throttle, sweeping smoothly to ~4.5V at wide-open throttle.. Failure: Voltage is consistently below the minimum threshold, often under 0.5V or even 0.2V.
• 5-Volt Reference at Throttle Body Connector (Key On, Engine Off) — expected: 4.8V to 5.2V.. Failure: Voltage is near zero or significantly below 4.8V, indicating a wiring issue or a problem with the ECM's 5V reference circuit.
• Low Reference (Ground) at Throttle Body Connector — expected: Less than 100 ohms of resistance to a known good chassis ground.. Failure: High or infinite resistance (open circuit), indicating a broken or corroded ground wire.
• Throttle Body Connector Pinout (Example for GM 3.6L) — expected: 6-Pin Connector: Pin E = 5V Reference; Pin C = Low Reference (Ground); Pin F = TPS 2 Signal; Pin D = TPS 1 Signal. Note: Pinouts can vary, always verify with a vehicle-specific diagram.. Failure: Incorrect or missing voltages when back-probing these specific pins.

Scan Tool Commands That Help

• GM Tech2 / GDS2: Throttle Actuator Test — This bidirectional control commands the throttle plate to open and close with the engine off. It allows a technician to visually and audibly confirm if the actuator motor is working smoothly or if it is sticking, binding, or making grinding noises.
• GM Tech2 / GDS2: Idle Learn / Throttle Body Relearn — This function must be used after replacing the throttle body to force the ECM to reset its learned idle airflow values. It is a more direct and reliable method than the manual relearn procedure and helps prevent a persistent high idle or related codes from appearing.

Wiring & Ground Locations

• Throttle Body Connector — The 6-pin electrical connector that plugs directly into the electronic throttle body assembly, located at the top rear of the engine where the air intake duct connects.. This is the single point of connection for power, ground, and both TPS signals. Corrosion, backed-out pins, or chafed wires at this connector are a primary cause of low voltage codes like P0222.
• G106 — A primary engine ground point. On some similar GM 3.6L platforms, it is located on the right rear of the engine.. The Engine Control Module (ECM) relies on solid ground connections. A loose or corroded G106 can cause erratic voltage readings and false sensor codes, including throttle position faults.
• Engine Control Module (ECM) — Located in the engine compartment on the left side, in front of the battery.. All throttle body wiring terminates here. If the throttle body and wiring test good, the fault could lie within the ECM itself, though this is rare.

OEM Part Supersession History

• 12595829, 12618735 → 12615503 — Updated design to address high failure rates of the internal throttle position sensors.
  Heads up: GM TSB 14582 noted that some vehicles were equipped with Bosch units and others with Hitachi units. The service procedure differed: Bosch units required full replacement, while some Hitachi units could be repaired with a new sensor kit. For a DIY repair, replacing the entire assembly with P/N 12615503 is the most straightforward approach.

Diagnostic Flowchart

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: A used OEM throttle body from a salvage yard can be a cost-effective alternative to a new part, especially since the failure mode is typically electronic rather than mechanical wear.

Donor-vehicle mileage cap: roughly under 75000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• Verify the part number on the used unit matches the OEM number or its supersessions (e.g., 12615503).
• Closely inspect the electrical connector pins. They must be straight, clean, and completely free of any green or white corrosion.
• Ensure the housing is not cracked or physically damaged.
• Check that the throttle plate moves freely by hand (if possible without causing damage) and is not seized.

Aftermarket brands forum-validated for this vehicle:

• ACDelco (GM Genuine)
• Dorman (specifically their 'OE FIX' line may offer improvements)
• Hitachi
• Spectra Premium

Real Owner Stories

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

Related OBD-II Codes

• P2135 — Throttle/Pedal Position Sensor/Switch 'A'/'B' Voltage Correlation. This is the most common companion code. It is set when the ECM detects a disagreement between the two internal throttle position sensors, strongly indicating a faulty throttle body assembly.
• P0122 — Throttle/Pedal Position Sensor/Switch 'A' Circuit Low Input. This code points to a fault in the primary throttle position sensor (TPS 'A'), while P0222 points to the secondary sensor (TPS 'B'). They often appear together when the internal electronics of the throttle body fail.
• P0507 — Idle Air Control System RPM Higher Than Expected. This code can appear after an improper repair attempt, such as cleaning the throttle body, or if a newly installed throttle body has not been calibrated correctly through the relearn procedure.
• P0223 — Throttle/Pedal Position Sensor/Switch 'B' Circuit High Input. This is the direct counterpart to P0222. It indicates the same sensor is sending a voltage signal that is too high, rather than too low, but still points to a failure within the electronic throttle body.

Frequently Asked Questions