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Technical Description of OBD-II Trouble Code
The circuit of the Evaporative Emission Control System Purge Control Valve is shorted.
This diagnostic trouble code (DTC) is a generic OBD-II powertrain code. It is considered generic because it applies to all makes and models of vehicles (1996-newer), although specific repair steps may vary depending on the model.
What does that mean?
On vehicles equipped with Evaporative emission control systems also known as EVAP, the engine draws in excessive fuel vapors from the gas tank that would otherwise be vented into the atmosphere.
The fuel vapor is routed through a vacuum line to the engine’s intake and the purge valve/solenoid controls the desired amount of fuel vapors, which is regulated by the vehicles powertrain control module (PCM) or engine control module (ECM). The PCM/ECM monitors the voltage to the purge control valve and has detected a lower voltage than expected.
Note: This code is similar to codes P0443 and P0444.
Symptoms
Symptoms of a P0445 trouble code may include:
Potential Causes
Possible causes of this DTC may include:
Diagnostic Steps for P0445 DTC
Engine wiring harness – Inspect the wiring harness connectors for damage, look for pinched wires, loose or bent pins, or bare wiring with no insulation. Typically, the purge control valve is powered by the battery and controlled on and off with a duty cycle through the PCM/ECM. Using the manufacturer’s wiring diagrams, identify which type of circuit is being used and check for the presence of battery voltage with the key on/engine off at the power side of the control solenoid connector using a digital volt ohm meter (DVOM) set to the volts scale. If no battery voltage is present, trace the wiring back to determine the cause.
Check for a short to ground by disconnecting the harness at the control valve solenoid and the source of voltage. Using the DVOM set to the ohms scale, with the negative lead connected to a known good ground and the positive lead on either end that supplies power to the control valve solenoid. If the resistance is very low, suspect a short to ground and repair the wiring harness. Check for a short to ground on the control side of the harness by disconnecting the harness from the control valve solenoid and the PCM/ECM harness. Identify the correct wire and using the DVOM set to ohms scale, check for resistance with the negative lead connected to a known good ground and the positive lead on either wire harness for the control circuit. If the resistance is very low, suspect a short to ground and repair the wiring harness.
Purge control solenoid – Check for continuity at the purge control solenoid connector pins after removing the harness plug using the DVOM set to the ohms scale. Verify that the resistance is within the manufacturer’s specifications. Check for a short to ground using the DVOM with the negative lead attached to a known good ground and the positive lead on each of the terminal pins to the control valve solenoid. The resistance should be very high or over limit (OL). If there is a very low amount of resistance found, suspect that the control valve solenoid is shorted to ground and replace it with a known good unit.
PCM/ECM malfunction – Since the EVAP is only turned on during certain driving conditions, it will be necessary to monitor the EVAP control operation using an advanced scan tool capable of performing a road test under the driving conditions required to activate the EVAP system. Some advanced scan tools have an internal test to activate the EVAP system manually. Verify that the PCM/ECM is commanding the EVAP system on. If the system is functioning correctly, it will be necessary to back probe the PCM/ECM wiring harness connector using a graphing multimeter or oscilloscope with a duty cycle feature with the positive lead on the purge control valve pin and the negative lead connected to a known good ground. The duty cycle should match what is commanded on by the PCM/ECM during EVAP operation. If there is no duty cycle present, the PCM/ECM may be at fault.
Other EVAP DTCs: P0440 – P0441 – P0442 – P0443 – P0444 – P0446 – P0447 – P0448 – P0449 – P0452 – P0453 – P0455 – P0456
Professional Service
Of course, we always recommend seeking professional mechanical assistance to resolve this issue. However, if for some reason this is not possible, we offer the option to permanently delete this specific DTC. All other codes will continue to be addressed. If you are interested in this option, please upload your ECU file to our portal.
