GF47.30-P-3016M Purge System With Leak Test Function

GF47.30-P-3016M Purge System With Leak Test Function
- MODEL 215, 220 with ENGINE 275.950
- with CODE (494) USA version
- MODEL 230 with ENGINE 275.951
- with CODE (494) USA version up to Model Year 08 /modification year 07
- MODEL 216, 221 with ENGINE 275.953
- with CODE (494) USA version up to Model Year 08 /modification year 07
- MODEL 230 with ENGINE 275.954
- with CODE (494) USA version up to Model Year 08 /modification year 07
- MODEL 215, 220 with ENGINE 275.980
- with CODE (494) USA version
- MODEL 230 with ENGINE 275.981
- with CODE (494) USA version up to Model Year 08 /modification year 07
- MODEL 216, 221 with ENGINE 275.982
- with CODE (494) USA version up to Model Year 08 /modification year 07
- MODEL 240 with ENGINE 285.950
- with CODE (494) USA version
- MODEL 240 with ENGINE 285.980
- with CODE (494) USA version





Shown on model 215, 220, 230, 240
17 Fuel rail 55/1 Fuel filter with integrated overflow valve
71 Check valve activated charcoal canister
74 ORVR vent line
75 Fuel tank
77 Activated charcoal canister
A1 Instrument cluster
A1e4 Fuel reserve indicator lamp
A1e26 "CHECK ENGINE" MIL
B4 Fuel level sensor
B4/3 Fuel tank pressure sensor
B4/7 Fuel pressure sensor
M3 Fuel pump
N3/10 ME-SFI [ME] control unit
Y58/1 Purge control valve
Y58/4 Activated charcoal filter shutoff valve
a Air admission of activated charcoal canister
b Air admission of fuel tank and overflow valve
c Intake manifold vacuum
CAN Data bus

The legislator requires that no fuel vapors reaches the open air.
The leak test must detect leaks of more than about 0.5 mm in diameter in the fuel evaporation control system. The test is performed in three stages (function chain):
- Test for major leak
- Check for a minor leak (equal to or greater than 1 mm)
- Check for fine leak (equal to or greater than 0.5 mm).

Test for major leaks
The activated charcoal canister shutoff valve is closed and the purge control valve opened. Intake manifold vacuum present in fuel tank.

This vacuum is measured by the tank pressure sensor.
If there is no vacuum build-up in the fuel tank (around -6 mbar within about 12 seconds), there is a major leak (e.g. filler cap open, loose hose line).
The test is aborted and the faults for the function chain and gross leak are stored.

If the motor electronics control unit detects a system with a substantial major leak, the fuel reserve warning lamp in the instrument cluster blinks and the message "CHECK GAS CAP" appears in the multifunction display.

Test for a minor leak
The purge control valve is closed at a vacuum of around -6 mbar.
The system is closed and thereby airproof. The vacuum is them measured for approx. 30 seconds. It must not drop any faster than 0.3 to 0.5 mbar per second (depending on the level of fuel in the tank). If the vacuum drops more rapidly, there is a fine leak.
The faults for function chain and minor leak are stored.

Check for micro leakage
If no minor leak has been detected, the purge system is briefly enabled and a vacuum of approx. -6 mbar is built up again. The vacuum must not drop any faster than 0.1 to 0.15 mbar per second for a closed system (depending on the level of fuel in the tank).
If the vacuum reduces more rapidly, the faults for function chain and micro leak are stored.

The reduction in the vacuum depends on the fill level in the fuel tank and on the degassing of the fuel. Degassing of the fuel is measured for a short time prior to the test and is allowed for in the fault statement.

The activated charcoal canister shutoff valve is reopened after the tests.

Test requirements
- Engine at idle
- Vehicle stationary
- Blocking time after engine start has lapsed (around 16 minutes) or mixture adaptation has been performed
- Lambda control enabled
- Intake air temperature less than +45°C
- Coolant temperature at engine start lower than +100°C
- Engine load less than 35%, transmission in drive stage D or R
- Air injection not active
- Air pressure more than around 780 hPa (i.e. no test is performed above a height of around 2500 m)
- Low loading of activated charcoal canister
- Fuel level in fuel reservoir between approx. 1/4 and 3/4 (CAN message from instrument cluster)
- The tank pressure sensor will detect whether the fuel in the fuel tank is swilling around excessively (impermissible pressure leaps) and the checking procedure is aborted if this the case
- No fault in the activated charcoal canister shut-off valve
- No fault in the fuel tank pressure sensor
- No fault on regeneration switchover valve (open/close)
- Battery voltage higher than 11 volts.

The test for minor and micro leaks is aborted if an excessive lean correction of the lambda control takes place during the build-up of the vacuum.
The function of the purge control valve is checked at the same time by the activation. If the closed valve jams, the fault gross leak is stored.

If no leak for the fault major leak is found (there is a clear hissing noise if there is a leak of more than 3 mm), replace fuel tank pressure sensor. The fuel tank pressure sensor may have a fault which results in a signal which is constant but still plausible (sensor sticking).
In the event of an implausible fill level resulting from a faulty fuel level sensor, tests are not inhibited.