P1413

Ford

SAI System Monitor Circuit Low Input

Definition source: Manufacturer reference catalog
Definition verification: Not independently verified for display.
Time: Varies by diagnosis and vehicle | Diagnostic difficulty: Medium
Medium Severity

The secondary air injection (SAI) system sends air into the exhaust to help control emissions. The vehicle’s control system monitors an SAI feedback circuit and has detected an input voltage that is lower than expected. This points to a circuit or monitoring problem; it does not by itself prove that the SAI pump or another specific part has failed. The exact system and diagnostic procedure depend on the vehicle’s model, year, and engine.

Report an error with this code

⚠️ Before You Begin (Safety First)

This code alone does not usually mean the vehicle is unsafe to drive. Have it diagnosed promptly because emissions control or inspection readiness may be affected. Stop driving if you also notice severe engine-running problems, overheating, smoke, or other urgent warning signs.

Common Symptoms

  • The check-engine light may be on.
  • There may be no noticeable change in engine performance because this is an emissions-system monitoring fault.
  • The SAI system may not operate or be confirmed as operating correctly, which can affect emissions.
  • An emissions inspection may be affected, depending on the vehicle and inspection rules.

Common Causes

  • A wire or connector in the monitor circuit may be damaged, corroded, loose, or shorted to ground.
  • Poor electrical supply, ground, or a connection with excessive resistance may pull the circuit input low.
  • A monitor switch or sensor, if used in that vehicle’s SAI system, may be faulty.
  • An open circuit can produce a low input on some circuit designs; vehicle-specific wiring information is needed to determine whether that applies.
  • A control-module fault is possible but should only be considered after the circuit and connected components are tested.

Diagnostic Steps

  1. Check for other diagnostic codes and record them before clearing anything; related codes can help narrow the fault.
  2. With the vehicle off and cool, visually inspect accessible SAI monitor wiring and connectors for looseness, corrosion, chafing, or obvious damage.
  3. Check the vehicle’s owner information for the location and access precautions for the SAI components; do not disconnect hot exhaust parts.
  4. If you have the correct wiring information and a multimeter, check accessible connections and circuit continuity only using the vehicle-specific procedure. Do not guess at pins or test values.
  5. If the circuit requires live signal testing or the fault is not obvious, have a qualified technician diagnose it before replacing parts.

When to Call a Professional

Use a scan tool to check for related codes and available SAI data, then follow the vehicle-specific wiring diagram to inspect and test the monitor circuit, its connections, and its power and ground. Confirm the circuit fault before replacing a pump, valve, sensor, or control module.

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Commonly Asked Questions

Does P1413 mean the SAI pump has failed?

No. The code identifies a low input in the SAI monitor circuit. Wiring, connections, power or ground, or a monitoring component may be responsible; the pump is not proven faulty by this code alone.

Does “low input” mean the system is moving too little air?

Not necessarily. It describes the electrical input detected in the monitor circuit, not a direct measurement of airflow.

Can I keep driving with this code?

If the vehicle runs normally and has no other urgent symptoms, the code alone usually does not require stopping immediately. Arrange diagnosis because emissions operation or inspection results may be affected.

What should be checked before replacing a part?

Check for related codes, inspect the monitor-circuit wiring and connectors, and test the circuit and connected components using model-, year-, and engine-specific service information.

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