A8L Quattro Sedan W12-6.0L (BSB) (2005)
If indication remains at approx 140 °C:
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End diagnosis and switch ignition off.
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Check wires to control module according to wiring diagram.
Check Wires to Control Module
Cylinder bank 1
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Connect test box to Engine Control Module (ECM) (J623) wiring harness on connecting test box for wiring test, refer to Repair Manual,
Cylinder bank 2
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Connect test box to Engine Control Module (ECM) 2 (J624) wiring harness on connecting test box for wiring test, refer to Repair Manual,
Cylinder bank 1 and 2
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Check wires between test box and 5-pin connector to Engine Control Module (ECM) for open circuit according to wiring diagram. Terminal
1+Socket 26, Terminal 3+Socket 27, wire resistance: max. 1.5 ohms
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Check wires for short circuit to each other, to vehicle Ground (GND) and to B+. Specification: infinite ohms
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Erase DTC memory of Engine Control Module => [ Diagnostic Mode 04 - Erase DTC Memory ] See: Computers and Control Systems/Testing
and Inspection/Scan Tool Testing and Procedures/Diagnostic Modes 01 - 09, Diagnostic mode 4: Reset/erase diagnostic data.
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Generate readiness code => [ Readiness Code, Generating ] See: Computers and Control Systems/Testing and Inspection/Monitors, Trips, Drive
Cycles and Readiness Codes.
If no malfunction is detected in the wiring:
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Measure resistance at Intake Air Temperature (IAT) sensor terminals 1 (signal) and 3 (Ground (GND)).