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.

  Indicated on display

  Fig 1: Displaying Rapid Data Transfer Screen

  Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
• Press buttons -0- and -8- to select "Read measured value block" function 08 and confirm entry with -Q- button.

  Indicated on display

  Fig 2: Displaying Read Measured Value Block Screen

  Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
• Press buttons -0-, -0- and -7- to select "Display group number 7" and confirm entry with -Q- button.
• Indicated on display
  Fig 3: Displaying Read Measure Value Block 7 Screen

  Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
• Observe coolant temperature figure in display field 4.
  • The temperature figure must increase uniformly and without interruption.

In the case of a malfunction the fuel temperature is displayed as a substitute.

• Press the --> button.
• Press buttons -0- and -6- to select "End output" function 06 and confirm entry with -Q- button.
• Switch ignition off.

If the display in field 4 appears unrealistic or the fuel temperature is displayed as a substitute, check the ECT sensor and wiring connections to the sensor as follows:

• Disconnect 4-pin connector from ECT sensor (arrow).
Fig 4: Disconnecting Pin Connector From ECT Sensor
Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
• Measure resistance between sensor terminals 1 (Ground) and 3 (signal).
Fig 5: Measuring Resistance Between ECT Sensor Terminals
Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

• Specification: correlate resistance measurement with chart
Fig 6: ECT Resistance Versus Temperature Graph
Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Examples:

• 30 °C corresponds to a resistance from 1500 to 2000
• 80 °C corresponds to a resistance from 275 to 375

If the specification is not obtained:

• Replace ECT Sensor -G62-, see item  13.
• 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 the specification is obtained:

• Remove wiper arms and plenum cover.

  See Plenum Cover Emoval & Installation

• Connect test box VAG 1598/22 (through my 1999) or VAG 1598/31 (from my 2000) to control module wiring harness.
Fig 7: Connecting Test Box Vag 1598/22 (Through My 1999) Or Vag 1598/31 (From My 2000) To Control Module Wiring Harness
Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
• Check wiring between test box and 4 -pin connector for open circuit according to wiring diagram:
  Fig 8: Identifying ECT Sensor Harness Connector Terminals

  Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
  ECT SENSOR HARNESS CONNECTOR TERMINAL SPECIFICATIONS
  
  

  	Test box socket no.
  Terminal	Through MY 1999	From MY 2000
  1	70	-
  3	54	112
  4	-	104

  • Wire resistance: max. 1.5 Ω
• Check wires for short to one another, to vehicle ground and to battery positive (B+).
  • Specification: INFINITY Ω
• If wiring and the resistance measurement values are OK, replace engine control module, see DIESEL DIRECT FUEL INJECTION (DFI) ENGINE CONTROL MODULE (ECM) -J248-, REPLACING .