Diagnostic Mode 8: Tank Leak Test

2003 Volkswagen Passat Wagon (3B6) L4-1.8L Turbo (AWM)SECTION Diagnostic Mode 8: Tank Leak Test


Diagnostic Mode 8: Tank Leak Test

NOTE: This diagnostic mode can only be selected with Module Number 10 - Engine Electronics.

Function
This diagnostic mode checks the fuel system for leaks.

NOTE: The Evaporative Emission (EVAP) Canister Purge Regulator Valve -N80- and Leak Detection Pump (LDP) -V144- seal the tank system.

Test requirements
- There must not be any DTCs stored in DTC memory. Diagnostic mode 3: Check DTC memory. Diagnostic Mode 3: Check DTC Memory
- Coolant temperature must be 80 to 110 degrees C. Diagnostic mode 1: Check measured values; PID 5, Coolant temperature. Diagnostic Mode 1: Check Measured Values
- Intake air temperature must not be above the maximum of 60 degrees C. Diagnostic mode 1: Check measured values; PID 15, Intake air temperature. Diagnostic Mode 1: Check Measured Values

Function test
- Connect diagnostic tester. Diagnostic Tester, Connecting
- Start engine and let run 15 minutes at idle.
- Under address word 33, select "Diagnostic mode 8: Tank leak test".
- Select measuring value "Test-ID 01: Tank leak test".
- Check specified value of tank leak test at idle.

Evaluation test-ID 01: Tank leak test







NOTE:
- During tank leak test, Engine Control Module (ECM) limits "test function active" to approx. 12 minutes.
- If the accelerator pedal is depressed during the test, the test will be aborted.
- To repeat the tank leak test, switch ignition off and start engine again and let run 15 minutes at idle.

- End diagnosis and switch ignition off.

If specified value is not obtained:
- EVAP canister system, checking for proper seal. Evaporative Emission (EVAP) Canister System, Checking For Proper Seal
- Check Evaporative Emission (EVAP) Canister Purge Regulator Valve -N80-. EVAP Canister Purge Regulator Valve Checking
- Leak Detection Pump (LDP) -V144-, checking. Leak Detection Pump (LDP), Check
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.