What does it mean?
On vehicles equipped with Evaporative Emission Control Systems, also known as EVAP, the engine draws excess fuel vapors from the gas tank that would otherwise be released into the atmosphere.
The fuel vapor is routed via a vacuum line to the engine intake, and the purge valve/solenoid measures the desired amount of fuel vapor, controlled by the Powertrain Control Module (PCM) or Engine Control Module (ECM). The PCM/ECM monitors the voltage to the purge control valve and has detected a voltage lower than expected.
Note: This code is similar to P0443 and P0444 codes.
Symptoms
Symptoms of a P0445 trouble code may include:
Check Engine Light illuminated (Malfunction Indicator Light on)
Slightly reduced fuel economy; this will not affect engine performance
Potential Causes
Causes
of this DTC may include:
Engine wiring harness or connector short circuit
Purge control solenoid short circuit
PCM/ECM malfunction
Diagnostic Steps
for P0445 DTC
Engine Wiring Harness – Inspect wiring harness connectors for damage, look for pinched wires, loose or bent pins, or bare wiring without insulation. Typically, the purge control valve is powered by the battery and triggered on and off with a duty cycle via the PCM/ECM. Using manufacturer wiring diagrams, identify the type of circuit used and check for battery voltage with the key on/engine off on the power supply side of the purge control solenoid connector using a Digital Volt-Ohm Meter (DVOM) set to the volts scale. If no battery voltage is present, trace the wiring to determine the cause.
Check for a short to ground by disconnecting the harness at the purge control valve solenoid and the voltage source. Using the DVOM set to the ohms scale, with the negative lead connected to a known good ground and the positive lead to each end that powers the purge control valve solenoid. If 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 purge control valve solenoid and the PCM/ECM harness. Identify the correct wire and using the DVOM set to an ohms scale, check resistance with the negative lead connected to a known good ground and the positive lead on one of the wiring harnesses of the control circuit. If resistance is very low, suspect a short to ground and repair the wiring harness.
Purge Control Solenoid – Check continuity at the purge control solenoid connector pins after removing the plug from the harness using the DVOM set to the ohms scale. Verify that resistance meets manufacturer specifications. Look 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 of the purge control valve solenoid. Resistance should be very high or above the limit (OL). If very low resistance is detected, suspect the purge control valve solenoid is shorted to ground and replace it with a known good unit.
PCM/ECM Malfunction – Since EVAP is only activated under certain driving conditions, it will be necessary to monitor EVAP control operation using a capable advanced scan tool and perform a road test under the required driving conditions to activate the EVAP system. Some advanced scan tools have an internal test to manually activate the EVAP system. Verify that the PCM/ECM is commanding the EVAP system. If the system is operating correctly, it will be necessary to probe the PCM/ECM wiring harness connector using a graphing multimeter or oscilloscope with a duty cycle function, with the positive lead on the purge control valve pin and the negative lead connected to a known good ground source. The duty cycle should match what is commanded by the PCM/ECM during EVAP operation. If no duty cycle is present, the PCM/ECM may be faulty.
Other EVAP DTCs: P0440 – P0441 – P0442 – P0443 – P0444 – P0446 – P0447 – P0448 – P0449 – P0452 – P0453 – P0455 – P0456