The P0222 trouble code is an OBD-II diagnostic code that indicates an issue with the throttle position sensor (TPS) or accelerator pedal position (APP) sensor circuit, specifically affecting the "B" circuit. This code often impacts throttle response and engine performance. This article provides a comprehensive analysis of P0222, covering its definition, causes, symptoms, diagnostic steps, and solutions. Supported by real-world case studies—such as issues in the Dodge Charger and other models—this guide offers practical insights for vehicle owners and technicians to effectively resolve this fault.

1. What is P0222?

P0222 is an OBD-II diagnostic trouble code (DTC) defined as "Throttle/Pedal Position Sensor/Switch B Circuit Low Input." It indicates that the Engine Control Module (ECM) has detected a voltage signal from the Throttle Position Sensor (TPS) or Accelerator Pedal Position (APP) sensor "B" circuit that is lower than the expected range (typically below 0.5 volts). This suggests a problem with the sensor, its wiring, or the ECM’s ability to interpret the signal.

Role of the Throttle/Pedal Position Sensor (B Circuit)

The TPS, located on the throttle body, and the APP sensor, located at the accelerator pedal, monitor the throttle valve position and driver input, respectively. In modern drive-by-wire systems, these sensors have multiple circuits (e.g., A, B, C) for redundancy and safety. The "B" circuit is one of these signal lines, providing a secondary voltage signal to the ECM. A low input on this circuit disrupts the ECM’s ability to accurately control the throttle, triggering P0222 and often activating a failsafe mode.

Common Trigger Conditions

• Voltage from the TPS/APP sensor B circuit is below the normal threshold.
• Electrical issues in the sensor circuit.
• Mechanical or sensor failures affecting signal accuracy.

2. Potential Causes and Specific Issues of P0222

P0222 can stem from various factors. Below is a detailed list of common causes, supported by real-world examples:

• (1) Faulty Throttle Position Sensor (TPS)
  Issue: The TPS is defective, sending a low voltage signal on the B circuit.
  Example: In a 2017 Dodge Charger, the TPS failed, outputting a 0.2V signal on the B circuit (normal: 0.5-4.5V), triggering P0222.
  Cause: Wear from prolonged use or exposure to heat and vibration.
• (2) Faulty Accelerator Pedal Position (APP) Sensor
  Issue: The APP sensor is malfunctioning, causing a low voltage on the B circuit.
  Example: A 2016 Chevrolet Impala exhibited P0222 due to a failing APP sensor, with the B circuit reading 0.3V.
  Cause: Internal sensor failure or wear in the pedal assembly.
• (3) Wiring or Connector Issues
  Issue: An open circuit, short to ground, or corroded connector in the B circuit causes a low voltage signal.
  Example: A 2018 Toyota RAV4 triggered P0222 because of a shorted ground wire in the TPS B circuit, dropping the voltage to 0V.
  Cause: Corrosion or physical damage from engine bay conditions.
• (4) Dirty or Malfunctioning Throttle Body
  Issue: Carbon buildup or mechanical issues in the throttle body affect TPS operation, leading to low voltage readings.
  Example: A 2015 Honda Pilot had P0222 due to a sticky throttle body, causing inconsistent TPS B circuit signals.
  Cause: Accumulated carbon deposits or throttle plate misalignment.
• (5) ECM Software or Hardware Issues
  Issue: The ECM misinterprets the TPS/APP sensor signal or has an internal fault.
  Example: A 2019 Nissan Maxima showed P0222 due to an ECM software glitch, resolved with a firmware update.
  Cause: Outdated software or ECM hardware failure.

3. Symptoms of P0222

Symptoms of P0222 are often related to throttle control and engine performance. Here are common signs and their associated causes:

• Check Engine Light On
  Symptom: MIL illuminates on the dashboard.
  Cause: ECM detects a low input on the TPS/APP B circuit.
• Reduced Engine Power (Limp Mode)
  Symptom: Vehicle enters a reduced power mode with limited acceleration.
  Cause: ECM activates failsafe mode to prevent unsafe operation.
• Unresponsive or Erratic Throttle
  Symptom: Throttle response is delayed, jerky, or inconsistent.
  Cause: ECM receives incorrect TPS/APP data, disrupting throttle control.
• Engine Stalling or Hesitation
  Symptom: Engine stalls or hesitates during acceleration.
  Cause: Improper throttle control due to faulty sensor signals.
• Poor Acceleration
  Symptom: Sluggish response when pressing the accelerator.
  Cause: Throttle not opening as commanded due to signal issues.

4. Vehicles Prone to P0222 and Case Studies

P0222 is common in vehicles with drive-by-wire throttle systems, particularly those with high mileage. Below are notable examples:

• Dodge Charger (2015-2020)
  Issue: Failed TPS.
  Symptom: Limp mode and poor acceleration.
• Chevrolet Impala (2014-2019)
  Issue: Faulty APP sensor.
  Symptom: Unresponsive throttle and MIL on.
• Toyota RAV4 (2013-2018)
  Issue: Shorted ground wire in the TPS B circuit.
  Symptom: Erratic throttle and stalling.
• Honda Pilot (2015-2020)
  Issue: Dirty throttle body.
  Symptom: Hesitation and reduced power.
• Nissan Maxima (2016-2021)
  Issue: ECM software glitch.
  Symptom: MIL on with intermittent throttle issues.

5. Steps to Diagnose P0222

Diagnosing P0222 requires a systematic approach. Follow these steps:

Step 1: Read Trouble Codes and Data Stream
Tool: OBD-II scanner (e.g., CR MAX).
Action: Connect to the OBD-II port, retrieve P0222 and related codes, and monitor live data.
Key Data:

1. 1. TPS B circuit voltage: Should range from 0.5V (closed) to 4.5V (wide open).
   2. APP B circuit voltage: Should increase with pedal movement (0.5-4.5V).

Example: The Charger showed a fixed 0.2V on the TPS B circuit.

Step 2: Visual Inspection
Checkpoints:

1. 1. TPS/APP sensor and connector: Look for damage or corrosion.
   2. Throttle body: Check for carbon buildup or mechanical issues.
   3. Wiring harness: Inspect for shorts, opens, or loose connections.

Example: The RAV4 had a shorted ground wire near the TPS.

Step 3: Test the TPS
Tool: Multimeter.
Action:

1. 1. Measure B circuit voltage: Should increase smoothly from 0.5V to 4.5V as the throttle opens.
   2. Check reference voltage: Should be 5V from the ECM.

Example: The Charger’s TPS B circuit showed a constant low voltage.

Step 4: Test the APP Sensor
Tool: Multimeter.
Action:

1. 1. Measure B circuit voltage: Should increase with pedal movement.
   2. Check resistance: Should be within specs (e.g., 1-5 kΩ).

Example: The Impala’s APP sensor B circuit read 0.3V consistently.

Step 5: Inspect the Throttle Body
Action:

1. 1. Clean the throttle body and retest TPS signals.
   2. Check for mechanical binding or sticking in the throttle plate.

Example: The Pilot’s throttle body was sticky, affecting TPS readings.

Step 6: Verify the ECM
Action:

1. 1. Test with a known-good TPS or APP sensor.
   2. Update ECM firmware if applicable.

Example: The Maxima’s issue resolved after a software update.

6. Solutions and Implementation

Apply these repairs based on diagnostic findings:

• Replace the TPS
  Part: Dodge OEM TPS (~$60).
  Steps: Disconnect the connector, remove the TPS, install a new one, and clear codes.
  Example: The Charger’s throttle response normalized post-replacement.
• Replace the APP Sensor
  Part: Chevrolet OEM APP sensor (~$100).
  Example: The Impala’s throttle control improved post-replacement.
• Repair Wiring or Connectors
  Method: Solder shorted wires or replace corroded connectors.
  Example: The RAV4’s wiring repair restored normal voltage.
• Clean or Replace the Throttle Body
  Part: Throttle body cleaner (~$10) or Honda OEM throttle body (~$150).
  Example: The Pilot’s hesitation stopped after cleaning.
• Update ECM Software
  Tool: Dealer equipment.
  Example: The Maxima’s P0222 cleared after the update.

7. Repair Costs and Precautions

• TPS: $60-$150.
• APP Sensor: $100-$200.
• Wiring Repair: $50-$150.
• Throttle Body Cleaning/Replacement: $10-$200.
• ECM Update: $0-$150.

Precautions

• Perform an idle relearn procedure after throttle body or TPS repairs.
• Use dielectric grease on connectors to prevent corrosion.

8. Preventive Measures

• Clean the throttle body every 30,000 miles to prevent buildup.
• Inspect wiring harnesses during routine maintenance.
• Avoid exposing the engine bay to excessive moisture or heat.
• Keep ECM software updated with manufacturer releases.

Summary

The P0222 trouble code indicates a low input issue in the throttle/pedal position sensor B circuit, often due to a faulty TPS, APP sensor, or wiring issues. Through detailed case studies—like the TPS failure in the Dodge Charger or the dirty throttle body in the Honda Pilot—and systematic diagnostics, this guide equips readers to diagnose and fix the problem efficiently. Addressing P0222 promptly restores throttle response, improves engine performance, and prevents unsafe driving conditions. For thorough diagnostics, tools like the iCarsoft CR MAX from www.icarsoft-us.com provide real-time data and code-clearing capabilities to maintain optimal vehicle operation.