EVAP Canister Purge Valve - Short to B+/Short to Ground

P0445

EVAP Canister Purge Valve - Short to B+/Short to Ground

Function
The fuel vapors from the fuel tank must not escape into the open air. For this reason, the ventilation line of the fuel tank is routed to an evaporative emission filter (or EVAP canister) that retains the fuel vapors. When driving, air is drawn in through the EVAP canister and picks up the accumulated fuel vapors and feeds them to the combustion process.
The EVAP canister purge valve is installed in the line between the EVAP canister and the intake system. The direction of flow through the valve is indicated by an arrow on the plastic housing.
The output stage that controls the EVAP canister purge valve is monitored.

Diagnosis conditions
A fault is detected and stored in the memory when the engine speed is over 80 rpm and the battery voltage lies between 7.5 and 17 V.

P0444-P0445:

Wiring Diagram

Diagnosis Procedure

DTC P0444

DTC P0445, Short to B+

DTC P0445, Short to Ground

1 Check voltage supply for EVAP canister purge valve.

1. Remove connector of EVAP canister purge valve.
2. Connect voltmeter (positive) to EVAP canister purge valve connector, pin 1, and ground.
3. Switch on the ignition.
Display: battery voltage

2 Check EVAP canister purge valve.

1. Remove connector of EVAP canister purge valve.
2. Connect ohmmeter to EVAP canister purge valve pins 1 and 2.
Display: 26 ± 4 ohms at 20 °C.

3 Check triggering wire for EVAP canister purge valve.

1. Remove connector of EVAP canister purge valve.
2. Connect special tool 9616 to wiring harness (DME control module connector).
3. Connect ohmmeter to EVAP canister purge valve, pin 2, and special tool 9616, pin 61.
Display: 0 - 5 ohms

4 Check triggering wire for EVAP canister purge valve for short circuit to B+.

1. Remove connector of EVAP canister purge valve.
2. Connect special tool 9616 to wiring harness (DME control module connector).
3. Connect voltmeter (positive) to EVAP canister purge valve connector, pin 2, and ground.
4. Switch on the ignition.
Display: 0 V

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

5 Check triggering wire for EVAP canister purge valve for short circuit to ground.

1. Remove connector of EVAP canister purge valve.
2. Connect special tool 9616 to wiring harness (DME control module connector).
3. Connect ohmmeter to EVAP canister purge valve connector, pin 2, and ground.
Display: Infinity ohm

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