Ata Circuit Operation - Navistar International DT 466 Diagnostic/Troubleshooting Manual

310 7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS

ATA Circuit Operation

Figure 381 ATA circuit diagram
The ECM communicates
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
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
with the EST and
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
• 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.
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.
DTC 231
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.
If