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Check engine speed sender > < Test intake air temperature sender - valid ? 07.97

Octavia Mk1

Test intake air temperature sender - valid 08.97 ?
Test intake air temperature sender - valid 08.97 ?
Special tools and workshop equipment required
t  Vehicle system tester -V.A.G 1552- with cable -V.A.G 1551/3-
t  Test box -V.A.G 1598/22-
t  Handheld multimeter (e.g. -V.A.G 1526-)
t  Measuring tool set (e.g. -V.A.G 1594 A-)
t  Current flow diagram
t  Cooling spray
  Note
t  The engine control unit functions with a replacement temperature of 19.5°C if a defect arises at the intake air temperature sender and/or in the wiring.
t  As of 08.97, the intake air temperature sender -G42- is a component part of the air mass meter -G70- and cannot be replaced individually.
Test sequence
–  Connect vehicle system tester -V.A.G 1552- and switch on ignition. Select the engine control unit using the address word 01. (Connecting up the vehicle system tester -V.A.G 1552- and selecting the engine electronics control unit → Chapter).
   
Readout on display:
–  Enter 08 for the function “Read measured value block” and confirm entry with the Q.
  
Vehicle system test                 HELP
Select function XX
Readout on display:
–  Enter 003 for the “display group number 3” and confirm entry with the Q key.
  
Read measured value block       HELP
Enter display group number      XXX
Readout on display: (1 to 4 = display fields)
–  Read off intake air temperature value in display field 4.
  
Reading measured value block 3        ->
800 rpm    13.580 V    96.0 °C     45.0°C
DisplayCauseContinue test
approx. -46°COpen circuit/Short circuit to positive → Anchor
approx. 141°CShort circuit to earth → Anchor
approx. ambient temperature1)- → Anchor

1) If a temperature is displayed that is below the ambient temperature of the sender, first check the sender wires for transition impedances. Make sure that the sender heats up or is heated by radiant heat.
Continuing test, if display approx. -46°C:
   
–  Disconnect the 5-pin plug -1- from air mass meter and intake air temperature sender.
  S24-0226
–  Bridge contacts 1 + 3 of the plug connection with adapter cables from -V.A.G 1594 A- and while doing so observe the read-out on the display.
If the read-out jumps to approx. 141°C:
–  Press → key.
–  Enter 06 for the function “End output” and confirm the entry with key Q.
–  Switch off ignition.
–  Replace air mass meter -G70- with intake air temperature sender -G42-.
If the read-out remains at approx. -46°C:
–  Press → key.
–  Enter 06 for the function “End output” and confirm the entry with key Q.
–  Switch off ignition.
  S24-0228
–  Connect test box -V.A.G 1598/22- at wiring loom to the engine control unit.
  S24-0148
–  Test wiring from 5-pin plug for the engine control unit sender according to the current flow diagram for line interruption as well as short-circuit to positive or earth.
  S24-0228
Contact at 5-pin plugContact to text box
140
312

If no fault is found:
–  Replacing engine control unit → Chapter.
Continuing test, if display approx. 141°C:
   
–  Disconnect the 5-pin plug -1- from air mass meter and intake air temperature sender.
If the read-out jumps to approx. -46°C:
–  Press → key.
–  Enter 06 for the function “End output” and confirm the entry with key Q.
–  Switch off ignition.
–  Replace air mass meter -G70- with intake air temperature sender -G42-.
If the read-out remains at approx. 141°C:
–  Press → key.
–  Enter 06 for the function “End output” and confirm the entry with key Q.
–  Switch off ignition.
–  Unplug connector from the engine control unit.
  S24-0226
–  Test wiring to engine control unit at 5-pin plug between contact 1 and 3, as well as between contact 1 and vehicle mass for short circuit.
Specified value: ∞Ω
If no fault is found:
–  Replacing engine control unit → Chapter.
Continuing test, if display approx. ambient temperature:
–  Remove intake air hose between air mass meter and throttle valve control unit.
–  Take down the intake air temperature value in display field 4.
  S24-0228
–  Spray the intake air temperature sender -arrow- with a commercially available refrigerant spray and while doing so observe the temperature value. The temperature value must drop.
–  Press → key.
–  Enter 06 for the function “End output” and confirm the entry with key Q.
  N24-0765

Check engine speed sender > < Test intake air temperature sender - valid ? 07.97