On Board Diagnostic

P0448

EVAP Canister Shutoff Valve (Output Stage) - Above/Below Limit

Function
The task of the shutoff valve is to seal the purge air line to the EVAP canister during the fuel tank leak test.

Diagnosis conditions
- Engine running
- Battery voltage greater than 7 V
- Fuel tank ventilation active

P0447 - P0448:

NOTE: Fuel tank ventilation can be activated with the Porsche System Tester 2 in the Short test menu.

Wiring Diagram







Diagnosis Procedure

DTC P0447







DTC P0448, Short to B+







DTC P0448, Short to Ground







1 Check voltage supply for shutoff valve.
1. Remove front right-hand wheel housing liner.
2. Remove connector of shutoff valve.
3. Connect voltmeter (positive) to shutoff valve connector, pin 1, and ground.
4. Switch on the ignition.
Display: battery voltage

2 Check shutoff valve.
1. Remove front right-hand wheel housing liner.
2. Remove connector of shutoff valve.
3. Connect ohmmeter to shutoff valve, pins 1 and 2.
Display: 22 - 26 ohms at 20 °C

3 Check triggering wire for shutoff valve for continuity.
1. Remove front right-hand wheel housing liner.
2. Remove connector of shutoff valve.
3. Connect special tool 9637 to wiring harness (DME control module connector).
4. Connect ohmmeter to shutoff valve, pin 2, and special tool 9637, pin IV/30.
Display: 0 - 5 ohms

NOTE: The wire is routed via connector X 2/5, pin 6.

4 Perform adaptation.
1. Switch on the ignition.
2. Wait one minute.
Do not press the accelerator.

3. Switch off the ignition for at least 10 seconds.
4. Read out the fault memory.

5 Check triggering wire for shutoff valve for short circuit to B+.
1. Remove front right-hand wheel housing liner.
2. Remove connector of shutoff valve.
3. Remove DME control module connector.
4. Connect voltmeter (positive) to shutoff valve connector, pin 2, and ground.
5. Switch on the ignition.
Display: 0 V

If battery voltage is displayed, check wiring harness for chafing and pinching damage.

6 Check triggering wire for shutoff valve for short circuit to ground.
1. Remove front right-hand wheel housing liner.
2. Remove connector of shutoff valve.
3. Remove DME control module connector.
4. Connect ohmmeter to shutoff valve connector, pin 2, and ground.
Display: infinity ohms

If 0 - 5 ohms is displayed, check wiring for chafing and pinching damage.