Fuel Tank Ventilation System, Checking

Fuel Tank Ventilation System, Checking

Evaporative Emission (EVAP) Canister Purge Regulator Valve (N80), checking

Special tools, testers and auxiliary items required

• Multimeter (V.A.G 1526 A)

• LED voltage tester (VAG1527B)

• Connector test kit (V.A.G 1594 A)

• Text box (VAG1598/31)

• Vehicle diagnostic, testing and information system ( VAS 5051)

• Adapter (VAS 5051/1)

Checking for leaks

Evaporative Emission (EVAP) Canister Purge Regulator Valve (N80) remains closed when de-energized.

- Disconnect hoses from EVAP Canister Purge Regulator Valve (N80) but leave electrical connector connected.

- Connect auxiliary hose to one connection of EVAP Canister Purge Regulator Valve (N80).

- Connect vehicle diagnostic, testing and information system (VAS 5051) or Scan Tool (V.A.G 1551) and select engine electronics control module with "Address word " 01. Refer to => [ VAS5051, Connecting and Selecting Functions ] VAS 5051, Connecting and Selecting Functions. Ignition must be switched on.

- Initiate output Diagnostic Test Mode (DTM) and activate EVAP Canister Purge Regulator Valve (N80). Refer to => [ Output Diagnostic Test Mode ] Output Diagnostic Test Mode.

• The valve should click...

• ...and should open and close (check by blowing into the auxiliary hose).

- End function "03 - Output Diagnostic Test Mode (DTM)" by pressing arrow button

If valve does not open or close properly:

- Replace EVAP Canister Purge Regulator Valve ( N80).

If the EVAP Canister Purge Regulator Valve (N80 ) does not click:

Checking internal resistance

- Disconnect connector on EVAP Canister Purge Regulator Valve (N80)-.

- Connect multimeter to fuel injector to measure resistance.





• Specified value: 22 to 30 ohms

If specified value is not obtained:

- Replace EVAP Canister Purge Regulator Valve ( N80).

If specified value is obtained:

Checking power supply

Requirements

• Fuse for Evaporative Emission (EVAP) Canister Purge Regulator Valve (N80) OK. Refer to

• Fuel pump relay OK; checking. Refer to => [ Fuel Pump Relay and Relay Activation, Checking ] Fuel Pump Relay and Relay Activation, Checking.

• The EVAP Canister Purge Regulator Valve (N80) receives its power supply via the fuel pump relay.

- Disconnect connector on EVAP Canister Purge Regulator Valve (N80).

- Connect LED voltage tester (VAG1527B) as follows:









- Operate starter briefly (engine may start).

• LED must light up.

If LED does not light up:

- Check wiring from terminal - 1 - on connector via fuse to fuel pump relay for an open circuit. Refer to

- Repair open circuit, if necessary.

If LED lights up:

Checking activation

- Connect LED voltage tester (VAG1527B) to terminals - 1 - (positive) and - 2 - of connector.





- Initiate output Diagnostic Test Mode (DTM) and activate EVAP Canister Purge Regulator Valve (N80). Refer to => [ Output Diagnostic Test Mode ] Output Diagnostic Test Mode.

• LED must flash.

If LED lamp does not flash or if it lights up continuously:

- Connect test box (VAG1598/31) to wiring harness for ECM; do not connect ECM. Refer to => [ Electrical Testing, with Test Box VAG 1598/31 ] Electrical Testing, With Test Box VAG 1598/31.

- Check for open circuit and short to positive (B+) or ground (GND) in following wiring connection:









- Repair any open/short circuit as necessary.

If the wiring is OK:

- Replace ECM. Refer to => [ Engine Control Module without Metal Anti-Theft Housing, Replacing ] Engine Control Module Without Metal Anti-Theft Housing, Replacing.