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Testing idling switch > < Function

A4 Mk1

Motronic Injection and Ignition System (4 cyl.)>06.96
Testing throttle valve control part J338
Performing basic setting of throttle valve control part J338

The basic setting to used to enable the Motronic control unit to learn the stop positions of the throttle valve control part with the ignition switched on and the engine not running.
If throttle valve control part J338 is removed and installed or replaced then a new basic setting must always be performed.

Test requirements:

  • ◆ Battery voltage OK.
  • ◆ Setting of throttle cable OK
  • ◆ All electrical consumers switched off
  • ◆ Setting of cruise control system, if fitted, OK
  • ‒ Interrogate fault memory, eliminate any displayed faults and delete the fault memory.
  • ‒ Switch off engine and switch on ignition.
  • ‒ Select basic setting with the engine not running (function 04) and Display group 98 =>Page 01-109.

Note:

After confirming Display group 98, the basic setting is started and the throttle valve positioner moves to both mechanical stops. Following this a comparison curve is calculated by means of intermediate steps.
 
→ Readout on display after approx. 6 seconds
Basic setting    98     ⇒
X.XXX V    X.XXX V    Idling    ADP. OK

The basic setting has been successfully carried out.

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→ If one of the following messages appears on the display, the basic setting has been terminated.
Basic setting    98     ⇒
X.XXX V    X.XXX V    Idling    ADP. not OK
 
Finish basic setting by pressing the ⇒key.
Basic setting    98     ⇒
X.XXX V    X.XXX V    Idling    ADP. running
 
Basic setting    98     ⇒
X.XXX V    X.XXX V    Idling    ERROR
 
Function is unknown or cannot
be carried out at the moment
  • ‒ Interrogate fault memory
 
→ If no fault is detected, check whether the idling switch opens and closes when the accelerator pedal is activated,Test idling switch =>Page 24-62.
No fault detected     ⇒
 
→ If one of these faults is displayed, check whether the idling switch opens and closes when the accelerator pedal is activated,Test idling switch =>Page 24-62.
Idling switch does not open     ⇒
Short to ground
 
Idling switch does not close     ⇒
Open circuit.
 
→ If this fault is displayed, test the voltage supply for the Motronic control unit (voltage at terminal 30 of the Motronic control unit has dropped below 10 V).
Supply voltage     ⇒
Signal too low
 
→ If one of the following faults is displayed, test the sender for throttle valve positioner -G127 and the throttle valve potentiometer =>Page 24-64.
Throttle valve positioner sender -G127    ⇒
Signal too low or too high
 
Throttle valve potentiometer -G69     ⇒
Signal too low or too high
 
Throttle valve positioner sender -G127    ⇒
Implausible signal

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Testing idling switch > < Function