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International DT466 – ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS – ATA Circuit Operation
The ECM communicates with the EST and MasterDiagnostics® software through the diagnostic
connector. The EST communicates with the ECM using the ATA datalink.
The IDM uses ATA only for programming.
The ATA circuit uses a twisted wire pair. All repairs must maintain one complete twist per inch along the
entire length of the circuit. This circuit is polarized (one positive and one negative) and reversing the polarity of this circuit will disrupt communications.
ATA Datalink Connector
Vehicles are equipped with the ATA datalink connector for communication between the Electronic Control
Module (ECM) and the EST.
The ATA datalink supports the following functions:
• Transmission of engine parameter data
• Transmission and clearing of DTCs
• Diagnostics and trouble shooting
• Programming performance parameter values
• Programming engine and vehicle features
• Programming calibrations and strategies in the ECM and IDM
Fault Detection / Management
The ECM continuously monitors the ATA datalink for an open, short or intermittent connection. If an active DTC occurs on the ATA datalink, the MasterDiagnostics® software will not display correct data.
The IDM uses ATA for programming only. DTCs are not transmitted from the IDM through the ATA datalink.
ATA Diagnostic Trouble Codes (DTCs)
DTCs are read using the EST or by counting the flashes from the amber and red ENGINE lamp.
ATA data communication link error
• DTC 231 is set when the ECM can not access the ATA datalink. When this occurs, ATA data can not be retrieved using the EST. DTCs can only be retrieved using the cruise control feature.
• DTC 231 can be set when any of the following conditions occur:
• Inoperative ATA device (transmission controller or anti-lock brake controller) is connected to ATA bus and pulls signal to ground.
• Number of ATA devices exceeds limit
• Inoperative ECM
• When DTC 231 is active the amber ENGINE lamp is not illuminated.
NOTE: Vehicles equipped with the Allison WTEC transmission may display DTC 231 when attempting to program the ECM. The WTEC controller must be disconnected when programming the engine ECM.
• EST with MasterDiagnostics® software
• EZ-Tech® interface cable
• Digital Multimeter (DMM)
• Breakout Box
• Breakout Harness
The ATA circuit requires the use of vehicle circuit diagrams.
See truck Chassis Electrical Circuit Diagram Manual for circuit numbers, connector and fuse locations.