Hyundai Accent 1996-1999, Elantra 1996-1999, Tiburon 1997-1999 Engine Vacuum

SERVICE MANUAL
Applies to: Accent1996-1999, Elantra1996-1999 and Tiburon1997-1999
GROUP
Emissions Control System

P0443 CIRCUIT DESCRIPTION

CODE: / P0443
CODE DESCRIPTION: / Evaporative Emissions Control System Malfunction
PRIMARY COMPONENT: / Purge Control Solenoid Valve
SECONDARY COMPONENT: / Fuel Tank Pressure Sensor, Barometric Pressure Sensor
SYSTEM(S): / Accent, Elantra, Tiburon (Bosch)
NORMAL PARAMETERS: / Purge Control Solenoid Valve (PCSV) resistance = 27 ohms

The evaporative system reduces hydrocarbon emissions by trapping fuel tank vapors until they can be burned as part of the incoming fuel charge. Evaporating fuel is stored in a charcoal canister until it can be flushed into the intake manifold.

The evaporative control system is made up of the following components:

  • Fuel tank that can be completely sealed from outside air
  • Fuel tank pressure sensor
  • Fuel/vapor separator that only allows vapor to enter the canister
  • Canister Close Valve (CCV) that seals the canister from the outside air
  • Canister filled with activated charcoal granules
  • Purge Control Solenoid Valve (PCSV)

In normal operation, the purge control valve opens and closes, depending on throttle angle and intake manifold vacuum. When it opens, fuel vapors are flushed from the canister and drawn into the intake manifold. To avoid a vacuum build-up in the canister, the canister close valve is normally held open to allow fresh air to replace the vapors drawn into the intake manifold.

FAILURE CONDITIONS

If the differential pressure in the evaporative control system is not within the specified ranges during two back-to-back trips, this code will be set and the Malfunction Indicator Light (MIL) will be turned on. When the system is fully closed, a vacuum should build up within a certain time. The code will set if the vacuum doesn't build up fast enough or the vacuum is too weak.

Details:

The code will be set if the following conditions are met:

  • Differential Pressure Sensor reads less than -8 hPa (1.85 volts) 5 seconds after the evaporative control system is fully closed OR differential pressure stabilizes at less than -30 hPa (0.10 volts)
  • Engine idling
  • Vehicle is not moving
  • Engine temperature at start-up is greater than 19°F (-7°C)
  • Altitude is less than 8,000 ft
  • Fuel tank pressure is less than 2 hPa (0.03 psi)
  • Fuel tank is at least 15% full
  • Engine has been running for at least 16 minutes

NOTE

Refer to the appropriate Electrical Troubleshooting Manual for full wiring details.

HDS TEST PROCEDURES

  1. Connect the HDS to the ECM of the vehicle to be tested using the appropriate connector.
  1. Enter the Simu-Tech module of the HDS. Enter the vehicle that is being tested in the Select Vehicle (1)option of the home screen.
  1. Select Signal Waveforms (2) from the Simu-Tech home screen.

  1. Select CAN CLOS (canister close valve), CAN PURG (canister purge control valve), and DPS (differential pressure sensor) (1) from the list of available signals. These signals must be selected in this sequence to follow the self-check test and capture the complete test trace.
  1. Select Analog Record from the Options (2) pull-down menu.

  1. Click the CTRL (1) button and select MS/DIV. Set the resolution to 300.00 MS/DIV (2) and click OK (3). By using this low resolution, the recording window is larger (112.13 seconds). The entire duration of the EVAP system self-check can then be recorded.
  1. Click the Run (4) button to start recording. With the engine running, trigger the EVAP system self-check using the hand-held scanner (follow the prompts on the scan tool). After the self-check is complete, click the HDS mouse button again to stop recording.

  1. There are several controls for viewing the recorded signal. Scroll moves the signal horizontally either forward or backward. Zoom enlarges or shrinks the signal. CTRL (Control) changes viewing options such as speed, digital or analog, and signal overlays. Refer to the Hyundai Diagnostic System User's Guide for complete details about the viewing controls.
  1. To view the total self-check waveform, select a zoom factor of -32. The example shown is a normal EVAP system self-check. Several aspects of the EVAP system are tested for integrity during this test. Refer to the HDS Signal Waveform Reference Manual for a complete breakdown of the self-check signals. This manual also has some examples of various problems and their related signals.

  1. Here is one example of a problem in the EVAP system that can be identified during the self-check. The EVAP system can be checked for a small leak by closing the system off from the outside air, creating a vacuum, and monitoring if the system can hold that vacuum sufficiently for a set amount of time. If it cannot, a leak exists in the system somewhere. In this example, the CAN CLOS is closed (zero volts), the CAN PURG is operating (activity in signal), and the DPS is indicating a drop in pressure. Once the CAN PURG stops operating, the DPS shows an increase in pressure, even though the CAN CLOS is still closed. This indicates a small leak somewhere in the system.

SCAN TOOL / DVOM TEST PROCEDURE

This was found at .

8/8/2006