A4 Sedan V6-2.8L (AFC) (1996)
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Eliminate short or open circuit in wiring using wiring diagram.
If wiring OK:
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Replace ECM.
Oxygen sensor heater, checking
NOTE:
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Z19 = Oxygen Sensor (O2S) heater, bank 1
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Z28 = Oxygen Sensor (O2S) heater, bank 2
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For functional check of O2S heaters -Z19- or -Z28-.
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Disconnect O2S heater connector -Z19- or -Z28- (component locations, refer to "Component Overview - II" See: Fuel Delivery and Air
Induction/Locations ).
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Switch multimeter (Fluke 83 or equivalent) to measure voltage and connect between terminals 1 (B+) and 2 (GND).
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Start engine and let idle.
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Specified value: approx. 12 to 14 volts
If the specified value is not obtained:
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Check oxygen sensor heater fuse.
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Check fuel pump relay See: Fuel Delivery and Air Induction/Fuel Pump/Fuel Pump Relay/Testing and Inspection
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Check wiring for continuity between terminal 1 and fuse in fuse holder using wiring diagram (if necessary check terminal assignments).
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Specified value: max. 1 ohms
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Check wiring for continuity between terminal 2 (O2S heater -Z19-) and terminal 10 on ECM connector E.
Specified value: max. 1 ohms
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Check wiring for continuity between terminal 2 (O2S heater -Z28-) and terminal 9 on ECM connector E.
Specified value: max. 1 ohms
If the specified value is obtained: