Code 0440

Tiny
YONY
  • MEMBER
  • 2001 CHEVROLET S-10
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 130,000 MILES
I replaced gas cap and purge solenoid. Valve but light comes on after a week.
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Tuesday, February 26th, 2019 AT 11:30 AM

1 Reply

Tiny
ASEMASTER6371
  • EXPERT
Good afternoon,

Below is the description of the code and the flow chart for determining the failure.

You need a scan tool that can read the system live data.

Roy

SYSTEM DESCRIPTION
The Evaporative Emission (EVAP) large leak test applies vacuum to the Evaporative Emission (EVAP) system and monitors vacuum decay. The Powertrain Control Module (PCM) monitors the Fuel Tank Pressure (FTP) sensor signal to determine the vacuum decay rate. At an appropriate time, the PCM turns the EVAP canister purge valve ON (open) and the EVAP vent valve ON (closed). This allows the engine to draw a vacuum on the EVAP system. At a calibrated time, or vacuum level, the PCM turns the purge valve OFF (closed), sealing the system, and monitors the FTP sensor input in order to determine EVAP system vacuum. If the system is unable to achieve the calibrated vacuum level, or the vacuum level decreases too rapidly, Diagnostic Trouble Code (DTC) P0440 will set.

CONDITIONS FOR RUNNING THE DTC
DTC P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0452, or P0453 are not set.
The ignition voltage is between 10-18 volts.
The Barometric Pressure (BARO) is more than 75 kPa.
The fuel level is between 15-85 percent.
The Engine Coolant Temperature (ECT) is between 4 -30 C (39 -86 F).
The Intake Air Temperature (IAT) is between 4 -30 C (39 -86 F).
The start up ECT and IAT are within 9 C (16 F) of each other.
The vehicle speed sensor (VSS) is less than 121 kmh (75 mph).

CONDITIONS FOR SETTING THE DTC
The EVAP System is not able to achieve or maintain vacuum during the diagnostic test.

ACTION TAKEN WHEN THE DTC SETS
The PCM will illuminate the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the diagnostic test ran and failed.
The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
The PCM will turn the Malfunction Indicator Lamp (MIL) OFF during the first consecutive trip in which the diagnostic has been run and passed.
A last test failed (current DTC) clears when the PCM turns OFF the MIL.
The history DTC will clear after the PCM runs and passes 40 consecutive warm up cycles with no failure.
The DTC can be cleared by using a scan tool.

DIAGNOSTIC AIDS
Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
Use the J41413 EVAP Pressure/Purge Diagnostic Station in order to pressurize the EVAP system to aid in locating intermittent leaks. Move all EVAP components while testing with the J41416 Ultrasonic Leak Detector.
A temporary blockage in the EVAP canister purge valve, purge pipe or EVAP canister could cause an intermittent condition. To repair a blockage in the EVAP system refer to Evaporative Emission (EVAP) System Cleaning.
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Tuesday, February 26th, 2019 AT 1:37 PM

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