Canister Purge Control Valve: Testing and Inspection
Evaporative Emission (EVAP) Canister Purge Regulator Valve, Checking
Required special tools and test equipment
- VAG 1551 or VAG 1552 Scan Tool (ST) with VAG 1551/3 adapter cable
Test conditions
- Engine coolant temperature at least 80 °C (176 °F)
Function check
- Connect VAG 1551 or VAG 1552 scan tool and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (with engine running at idle). Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG 1551/1552 Scan Tool" Testing and Inspection
Indicated on display
Rapid data transfer HELP
Selecting function XX
- Press buttons -0- and -8- to select "Read Measuring Value Block" function 08, and press -Q- button to confirm input.
Indicated on display
Read Measuring Value Block HELP
Input display group number XXX
- Press buttons -0-, -7- and -0- to input display group number 70, and press -Q- button to confirm input.
Indicated on display (1-4 = display fields)
Read Measuring Value Block 70 ->
1 2 3 4
- Press -4- button- to select "Basic Setting" function 04 (diagnosis for EVAP canister purge regulator valve is initiated).
NOTE: During this diagnosis there should not be any load placed on the engine, otherwise the diagnosis is interrupted and must be started again.
Indicated on display (1-4 = display fields)
System in Basic Setting 70 ->
1 2 3 4
If the diagnosis is initiated by the ECM, the display changes from "Test OFF" to "Test ON" in display field 4.
- Continue to run engine at idle until "EVAP OK" is indicated in display field 4.
NOTE: If the display changes from "Test ON" to "Test OFF" during the test, accelerate with a brief burst to repeat the test
Display Group 70:
If "EVAP not OK" is indicated in display field 4:
- Check for blockage or leaks.
If "EVAP OK" is indicated in display field 4:
- Press -> button to advance program sequence.
Indicated on display
Rapid data transfer HELP
Selecting function XX
- Press buttons -0- and -6- to select "End Output" function 06, and press -Q- button to confirm input.
Checking for blockage and leaks
The EVAP canister purge regulator valve is closed when power is off.
- Remove EVAP canister purge regulator valve -N80-.
- Connect removed valve to harness connector.
- Start output Diagnostic Test Mode (DTM) and select -N80-. Refer to "Scan Tool Testing/Output Diagnostic Test Mode (DTM) (Function 03)" Testing and Inspection
- Blow into long connection during output DTM, and check whether valve opens and closes properly. Replace valve if necessary.
- If valve is OK, check all hose connections between tank and valve for blockage or leaks.
EVAP canister purge regulator valve -N80- electrical test
- Disconnect harness connector from EVAP canister purge regulator valve.
- Connect multimeter US 1119 (Fluke 83 or equivalent) and check resistance at across valve terminals.
Specified value: 22 - 30 Ohms
If resistance is NOT OK:
- Replace EVAP canister purge regulator valve
Checking EVAP canister purge regulator valve voltage supply
Test conditions
- Fuse for EVAP canister purge regulator valve OK.
- Disconnect harness connector from EVAP canister purge regulator valve.
- Connect VAG 1527B LED voltage tester between connector terminal 1 and engine Ground.
- Operate starter motor. Specified value: LED must light up
If LED test light does not light:
- Check wiring for open circuit between connector terminal 1 and fuse, according to wiring diagram. Repair if necessary.
If wiring is OK:
- Check fuel pump relay. Testing and Inspection
Checking signal to EVAP canister purge regulator valve
- Connect VAG 1527B LED voltage tester between connector terminals 1 (B+) and 2.
- Start output Diagnostic Test Mode (DTM) for EVAP canister purge regulator valve -N80-. Refer to "Scan Tool Testing/Output Diagnostic Test Mode (DTM) (Function 03)" Testing and Inspection
LED must blink
If LED test light does not blink, or stays on:
- Connect VAG 1598/22 test box to ECM harness connector. Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG 1598/22 Test Box" Testing and Inspection
- Check wiring for open circuit or short circuit to B+ between connector terminal 2 and Motronic ECM terminal 15.
If wiring is OK:
- Replace Motronic ECM -J220-.
- Carry out adaptation of throttle valve control module to ECM.
- Check readiness code. If Diagnostic Trouble Code (DTC) memory has been erased, or ECM was disconnected, generate new readiness code.
Refer to "Monitors, Trips and/or Drive Cycle/Displaying Readiness Code" Testing and Inspection
Refer to "Monitors, Trips and/or Drive Cycle/Generating Readiness Code" Testing and Inspection