Test sequence

• Connect V.A.G 1551/1552 (Connecting scan tool and selecting engine electronics control module. See VAG 1551 SCAN TOOL, CONNECTING .)
• Run engine at idle speed and press buttons -0- and -1- to select "Engine electronics" address word 01.
  WARNING: Secure Scan Tool to rear seat and operate from this position (second technician required).

  Indicated on display

  Fig 1: Scan Tool Display - Checking Mass Air Flow (Maf) Sensor (1 Of 5)

  Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
• Press buttons -0- and -8- to select "Read measured value block" and confirm entry with -Q- button.

  Indicated on display

  Fig 2: Scan Tool Display - Checking Mass Air Flow (Maf) Sensor (2 Of 5)

  Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
• Press buttons -0-, -1- and -0- to select "Display group number 10" and confirm entry with -Q- button.
• Observe display in display field 1.
  Fig 3: Scan Tool Display - Checking Mass Air Flow (Maf) Sensor (3 Of 5)

  Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
  • Specification: 230 to 370 mg/H

If the specification is not obtained:

• Check exhaust gas recirculation system:

  See EXHAUST GAS RECIRCULATION, CHECKING

  If the specification is obtained:

• Road test vehicle with a 2nd technician to observe display.

  Observe valid safety precautions when road testing, see SAFETY PRECAUTIONS .

• Accelerate vehicle in 3rd gear (vehicles with manual transmission) or 2nd gear (vehicles with automatic transmission) from about 1500 rpm using wide open throttle.
• Press PRINT button on V.A.G 1551 at approx. 3000 rpm.
  • Specification in display field 4: 100 % (accelerator pedal position)
  Fig 4: Scan Tool Display - Checking Mass Air Flow (Maf) Sensor (4 Of 5)

  Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

If the specification is not obtained:

• Repeat test and accelerate vehicle at wide open throttle.
  • Specification in display field 1: above 800 mg/H (mass of air drawn in).
  Fig 5: Scan Tool Display - Checking Mass Air Flow (Maf) Sensor (5 Of 5)

  Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
• Press --> button.
• Press buttons -0- and -6- to select "End output" function 06 and confirm entry with -Q- button.
• Switch ignition off.

  If the specification is not obtained:

• Replace MAF Sensor -G70-, see item  10.
• Check DTC memory and, if necessary, repair any malfunctions and then erase. See DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING AND ERASING .
• Read readiness code, see READINESS CODE, DISPLAYING .

If the DTC memory has been erased or the engine control module was disconnected from permanent battery positive (B+), the readiness code must be generated again. See READINESS CODE, SETTING .

If a constant 550 mg/H (predetermined replacement value) is displayed in field 1: