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Re: Body code for 2001 Z06 corvette
DTC U1064 Loss of Communications with BCM
Circuit Description
The serial data circuit is used to communicate information between each system connected to the serial data line. Each system is assigned a specific recognition code (source ID). This code is used to identify which system is communicating on the serial data line. Systems communicate with others by periodically sending messages on the serial data line. These messages contain specific information (or commands) a system requires to function properly. When a system receives a message it also learns the source ID of the system that sent it. This source ID is used to determine which system actually sent the message and for State of Health (SOH) monitoring. SOH monitoring determines if a system is unable to communicate properly. Systems periodically send a SOH message to each other containing their source ID. If a system fails to receive a SOH message back from a system that it communicates with, then a DTC identifying what system did not respond will set.
Conditions for Setting the DTC
A system sends out a (SOH) message on the serial data line to the Body Control Module (BCM), and no SOH message response was sent back.
Condition must be present for 5 seconds.
Action Taken When the DTC Sets
Stores a DTC U1064 in the system that was unable to communicate with the BCM.
The system unable to communicate with the BCM may set false DTCs and substitute default values for certain functions.
No driver warning message will be displayed for this DTC.
Conditions for Clearing the DTC
This DTC requires an ignition cycle in order to change from current to history.
A system sends out a (SOH) message on the serial data line to the BCM, and a SOH message response was sent back.
A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.
Use the IPC clearing DTCs feature.
Use a scan tool.
Diagnostic Aids
If the problem is an intermittent loss of communications. Carefully inspect the serial data line and related components for the following intermittent conditions:
There is an intermittent open or short (to ground or voltage) in the serial data line.
Intermittent loss of communication with the BCM.
Damaged or loose star connector terminals.
Poor connections/terminal tension at a harness connector.
Intermittent BCM communication due to a loss of power or ground to the BCM.
Communication DTCs do not necessarily indicate a malfunction. These DTCs are only intended to aid in diagnosing an intermittent communication malfunction that is accompanied by a symptom. If the vehicle does not experience a symptom related to a communication malfunction, these DTCs can be disregarded.
If the serial data line is shorted to ground or shorted to voltage, all systems connected to the same serial data line will not be able to communicate properly. Systems capable of storing loss of communication DTCs (DTCs with the letter U as a prefix) will have these codes stored in their memory. If a DTC U1064 is stored in a system's memory, check for the same DTC stored in other systems capable of setting a DTC U1064. The IPC, RFA, LDCM and RDCM all monitor the SOH message from the BCM. If other systems have a DTC U1064 stored, check the BCM for an intermittent malfunction. If other systems do not have a DTC U1064 stored, check for an intermittent malfunction in the system that set a DTC U1064. After repairing a DTC U1064, clear all DTCs from all systems capable of storing communication DTCs.
DIC Onboard Diagnostics Show DTCs U1016, U1064 and U1096 in History #PI00043 - (Jun 19, 2002)
DIC Onboard Diagnostics Show DTCs U1016, U1064 and U1096 in History.
When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.
Condition/Concern:
DTCs U1016, U1064 and U1096 may be present when scrolling through the onboard diagnostics via the instrument cluster Driver Information Center (DIC).
Recommendation/Instructions:
This is a normal software function as long as the DTCs have a history status upon ignition cycling. No repair attempts should be made.
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