Diagnostic trouble code P1223 is a manufacturer-specific powertrain fault code. Because it is manufacturer-specific, its exact definition depends entirely on the vehicle make, model, and application.
Exact vehicle application must be verified before diagnosis. The code identifies a detected condition in a specific subsystem, but further testing is required to identify the root cause.
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Key Takeaways
- P1223 is a manufacturer-specific code, meaning its definition varies between automakers like Nissan, Ford, and General Motors.
- On Nissan and Infiniti applications, it indicates a Throttle Position Sensor 2 or Pedal Position Sensor 2 circuit low input fault.
- On Ford applications, it points to a Pedal Demand Sensor B circuit high input condition.
- On certain GM applications, it indicates an injection control circuit commanded state mismatch or injector output circuit fault.
- Diagnosis requires verifying the exact factory definition and testing the relevant sensor or injector circuits.
P1223 Code Description and Implications
Because P1223 is manufacturer-specific, there is no single universal definition. This error code identifies a detected condition, but the exact monitored system depends on the vehicle make and model.
Some Nissan and Infiniti applications: P1223 indicates a “Throttle Position Sensor 2 Circuit Low Input” or “Pedal Position Sensor 2 Circuit Low,” meaning the engine control module detects a voltage signal below the expected range.
Certain Ford and Land Rover applications: P1223 indicates a “Pedal Demand Sensor B Circuit High Input,” pointing to an excessively high voltage signal in the accelerator pedal position sensor circuit.
Some General Motors applications: P1223 indicates an “Injection Control Circuit Commanded State to Actual State Mismatch” or an injector output circuit fault, relating to fuel delivery control.
Common Causes of the P1223 Code
The underlying cause depends entirely on the verified factory definition for the specific vehicle application.
For Nissan, Infiniti, and Ford applications, possible causes include a failing throttle position sensor, a faulty accelerator pedal position sensor, damaged wiring, or poor electrical connections in the sensor circuit.
For GM applications, causes may involve a failing fuel injector, damaged injector control wiring, or an internal engine control module fault.
Symptoms Associated With P1223
Symptoms vary depending on the underlying system fault and the vehicle manufacturer.
On applications monitoring the throttle or pedal position sensors, symptoms can include poor acceleration, rough idling, unresponsive throttle input, and an illuminated Check Engine Light.
On GM applications with an injection control circuit fault, symptoms may include severe engine misfires, loss of power, excessive exhaust smoke, and difficulty starting the engine.
Diagnosing the P1223 Trouble Code
Diagnosis must begin by confirming the exact factory definition for the specific make, model, and year.
For throttle and pedal sensor applications, technicians inspect the sensor wiring harness for opens, shorts, or corrosion, and test the sensor signal voltage and ground circuits using a multimeter or scan tool.
For GM injection control applications, technicians test the injector circuit resistance, inspect the injector wiring for damage, and verify the control module signals.
Repairing the P1223 Issue
Repairs must follow confirmed diagnosis based on the specific vehicle application.
If a sensor circuit fault is confirmed, the damaged wiring must be repaired, corroded connectors replaced, or the failing throttle or pedal position sensor replaced according to manufacturer procedures.
If an injection control circuit fault is confirmed, the failing fuel injector or damaged control wiring must be replaced.
Cost Considerations for P1223 Repairs
Cost depends on diagnostic time, component accessibility, required parts, programming requirements, and labor.
Replacing an external pedal position sensor or repairing damaged wiring may require minimal labor depending on accessibility.
Conversely, replacing an internal throttle position sensor on an integrated throttle body assembly or replacing fuel injectors requires significant labor and specialized calibration procedures.
Prevention Strategies for Future Occurrences
Some electrical and mechanical failures cannot be reliably prevented.
Inspecting exposed wiring harnesses near the accelerator pedal and throttle body for chafing, moisture intrusion, or physical damage can help prevent intermittent circuit faults.
Keeping electrical connectors clean and ensuring connector seals remain intact may reduce corrosion that leads to signal circuit failures.
Troubleshooting Tips and Best Practices
Never assume P1223 is a universal throttle or injector code. Always verify the exact definition for the specific vehicle before purchasing parts.
Do not ignore related codes. A pedal position sensor fault may appear alongside other throttle correlation codes, while an injector fault may appear alongside multiple misfire codes.
Check for technical service bulletins applicable to your exact vehicle application, as manufacturers frequently release updated sensor assemblies or revised wiring harnesses for recurring faults.
More OBD-II Codes
| P1222 | P1224 | P0121 | P1106 |
| P1221 | P1225 | P0122 | P1107 |
| P1220 | P1226 | P0123 | P1118 |
| P1219 | P1227 | P0220 | P1119 |
| P1218 | P1228 | P0222 | P1121 |
| P1217 | P1231 | P0223 | P1122 |
Frequently Asked Questions
Is P1223 a generic or manufacturer-specific code?
No. P1223 is a manufacturer-specific code. Its exact definition varies significantly between automakers, so the factory service information for the specific vehicle must be consulted.
Can I drive my car with a P1223 code?
It depends on the application. If P1223 indicates a pedal position sensor fault, the vehicle may enter limp mode or experience unresponsive acceleration, creating a safety hazard.
Will disconnecting the battery clear the P1223 code?
Disconnecting the battery may temporarily clear the code, but it does not repair the underlying electrical or mechanical fault. The code will return once the monitor runs again.
Can a dirty throttle body cause a P1223 code?
On applications monitoring the throttle position sensor, severe carbon buildup can restrict the throttle plate movement, potentially causing the sensor signal to fall outside the expected range.
Does P1223 always mean the sensor or injector is bad?
No. While a failing component is a cause on specific applications, the code can also indicate damaged wiring, a short to ground or voltage, or a poor electrical connection.
What Should You Do About the P1223 Code?
Confirm the exact factory definition and diagnostic procedure for your specific vehicle application. Because P1223 is manufacturer-specific, identifying whether it relates to a throttle position sensor, a pedal demand sensor, or an injection control circuit is mandatory.
Follow the applicable manufacturer diagnostic steps to test the relevant system and components. Once the root cause is confirmed, complete the necessary repairs and verify that the system operates correctly and the code does not return.
