Checking functions
Idling check
Notes:
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◆ Idling speed, ignition timing and CO content not adjustable.
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◆ The idling speed is regulated to specification by the throttle valve positioner in conjunction with the DIS function.
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◆ CO content regulated by lambda regulation. Faults in lambda control are detected in self-diagnosis and stored in fault memory.
Special tools, workshop equipment, testers, measuring instruments and auxiliary items required
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◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
Test conditions
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● Exhaust system between cylinder head and catalytic converter free of leaks
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● Coolant temperature must be at least 80 °C, =>display group 04, display zone 3.
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● All electrical consumers, e.g. lights and rear window heating must be switched off
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● If the vehicle is equipped with an air conditioning system, this must be switched off.
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● On vehicles with automatic gearbox selector lever in "P" or "N" position
Test sequence
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‒ Connect fault reader V.A.G 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control unit. When doing this the engine must be running at idling speed.
(Connecting fault reader and selecting engine control unit .)
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‒ Interrogate fault memory, if necessary, repair fault and then erase fault memory.
=> Page 01-19, interrogating and erasing fault memory
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‒ Then:
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‒ Leave fault reader V.A.G 1551 connected.
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‒ Continue running engine at idling speed.
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