volkswagen Workshop Repair Guides

Volkswagen Workshop Service and Repair Manuals

Checking modulating piston movement sender G149 and metering adjuster N146 > < Checking intake manifold temperature sender G72
Checking fuel temperature senderG81
Checking fuel temperature sender -G81-
Special tools and workshop equipment required
t  Hand multimeter -V.A.G 1526C- or multimeter -V.A.G 1715-
t  Fault reader -V.A.G 1551- or vehicle system tester -V.A.G 1552- with diagnosis cable -V.A.G 1551/3-
t  Adapter set -V.A.G 1594C-
t  Adapter cable, 121-pin -V.A.G 1598/31-
t  Current flow diagram
Test procedure
–  Connect fault reader -V.A.G 1551- or vehicle system tester -V.A.G 1552- and select engine electronics control unit with “address word” 01. Engine must be idling. (Connecting fault reader -V.A.G 1551- and selecting engine electronics control unit → Chapter).
   
Indicated on display:
–  Press keys 0 and 8 for function “Read measured value block” and confirm entry with Q key.
 
Rapid data transfer                 HELP
Select function XX                    
Indicated on display:
–  Press keys 0, 0 and 7 for “Display group number 7” and confirm entry with Q key.
 
Read measured value block                     
Input display group number XXX       
Indicated on display:
–  Check fuel temperature value in display zone 1. The temperature value must be approx. ambient temperature.
–  If a fault is present, a constant fuel temperature of -5.4°C is displayed.
–  Press key.
–  Press keys 0 and 6 for function “End output” and confirm entry with Q key.
–  Switch off ignition.
–  If no realistic display appears in display zone 1 or a substitute temperature of -5.4 °C is displayed, check fuel temperature sender -G81- and wiring to sender as follows:
 
Read measured value block 7          ->
15.4°C            15.9°C       16.7°C
–  Disconnect 10-pin connector for fuel temperature sender -G81- (connector to injection pump quantity adjuster).
  N23-0368
–  Measure sender resistance at connector contacts 4+7.
  A23-0027
Specification see diagram.
Scale A shows resistance values for temperature range 0...50 °C and scale B the values for temperature range 50...100 °C.
Examples:
t  30 °C corresponds to a resistance of 1500..2000 Ω
t  80 °C corresponds to a resistance of 275..375 Ω
If the specification is not achieved:
–  Renew injection pump → Chapter, Removing and installing injection pump.
–  Read fault memory, if necessary, repair any faults and then clear fault memory → Chapter, Reading and clearing fault memory.
If the specification is attained:
  N24-0157
–  Connect adapter cable, 121-pin -V.A.G 1598/31- to control unit wiring harness. The engine control unit remains disconnected.
  N01-0369
–  Check wiring between adapter cable, 121-pin -V.A.G 1598/31- and connector for open circuit referring to current flow diagram. Contact 4 + socket 103 Contact 7 + socket 111.
Cable resistance: max. 1.5 Ω.
–  Also check wiring for short to one another, short to vehicle earth and short to battery positive.
Specification: ∞ Ω.
If no fault in lines is detected:
–  Renew engine control unit → Chapter.
  A23-0028

Checking modulating piston movement sender G149 and metering adjuster N146 > < Checking intake manifold temperature sender G72