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The evaporative emission control (EVAP) system prevents fuel vapors from entering the atmosphere by storing the vapors in a charcoal canister. A P0445 code gets logged if the system detects an anomaly in the purge flow from the EVAP system, indicating a potential issue with the operation of the purge control valve.

What Does the P0445 Code Mean?

Diagnostic trouble code (DTC) P0445 stands for “Evaporative Emission System Purge Control Valve “A” Circuit Shorted.” It indicates a potential issue with the purge control valve or its circuit.

Code P0445 refers to the canister purge valve, which is typically a valve opened by a solenoid that is duty cycled by the ECM/PCM to allow fuel vapor stored in the canister to enter the intake manifold. As such, this solenoid is usually powered up on one side and the ECM/PCM cycles the ground on the other side of the circuit.

The code indicates that the solenoid is shorted (an open would mean a broken winding or a cut wire). If the trigger wire (the ground that cycles) is shorted to power it can also store this code.

mechanic obd code 1
Code P0445 may be stored if the PCM perceives a potential problem with the purge valve or its circuit.

The ECM/PCM knows when it is purging and there are “cells” in the algorithm map that factor in canister purging for air fuel mixture control purposes, because adding fuel vapor to the intake has an impact on fuel trim strategy. Cells in the algorithm where no purging is supposed to take place are flagged by the algorithm as “purge free” cells.

The B+ side of the purge solenoid will typically be fed by a relay, and the ground side of the solenoid will be duty-cycled by the ECM/PCM as the algorithm dictates.

The PCM performs various tests on the EVAP system. If the module perceives a short circuit (wires touching when they shouldn’t) with the purge valve or its circuit, it turns on the check engine light and stores code P0445 in its memory.

A Quick Note About Short Circuit and Open Circuit

Let’s digress for a moment here to note that a “short circuit” and an “open circuit” are two different situations. A “short” would be wires making contact with ground or each other, and an “open” would be like a cut wire. An open circuit won’t usually damage the ECM/PCM but a short circuit has the potential to ruin elements of the ECM/PCM’s circuitry.

car open circuit by Richard McCuistian
This photo illustrates an open circuit. If these two wires were melted together, that would be a short circuit. | Image source: Richard McCuistian.

What are the Possible Causes of the P0445 Code?

The purge control valve regulates the purge flow of fuel vapor in the engine. This narrows down the likely causes of the P0445 code to:

  • Failed purge valve
  • Purge valve circuit issues, such as damaged wires or poor connections
  • PCM issues, such as software in need of an update (note: very rare) or, more commonly, a failed driver circuit

What are the Common Symptoms of the P0445 Code?

This problem may cause the following symptoms:

Sometimes, the vehicle will not display any warning signs associated with the P0445 code. Plugging a scan tool into the OBD port can confirm the presence of the diagnostic trouble code.

How to Diagnose the P0445 Code

Hunting down the cause of the P0445 code can prove daunting for anyone with minimal or no experience in car repair. Unless you know your way around your car’s EVAP system like it was the back of your hand, leave it to a professional mechanic or technician.

For an idea of what the troubleshooting process might involve, check out these videos:

How to Fix the P0445 Code

Once you’ve determined what triggered the P0445 code, figure out how to resolve the issue. Make sure to research a solution that’s specific to your vehicle’s year, make, and model. Consult online auto repair resources and guides to determine the right way to resolve the code P0445.

Other Notes About P0445

The Society of Automotive Engineers (SAE) set the generic code P0445. Your vehicle’s manufacturer may have a definition for the code, so a 2004 Ranger P0445 case may not resemble or resolve in the same way as a P0445 Toyota incident.

This code resembles P0443 (EVAP Control System Purge Control Valve Circuit) and P0444 (EVAP Purge Control Valve Circuit Open). P0443 triggers if the solenoid controlling the valve doesn’t display the right voltage or shows signs of an open circuit. In comparison, a P0444 gets logged when the solenoid shows no activity after the PCM ordered the purge valve opened.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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