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1999 Cadillac Seville STS; AMP U1064 code meaning ?

Old 07-29-2009, 07:56 AM
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Default 1999 Cadillac Seville STS; AMP U1064 code meaning ?

having trouble finding what AMP U 1064 code means.... 99 seville sts

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Last edited by Stealth; 07-30-2009 at 09:11 AM.
Old 07-29-2009, 10:30 AM
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Do***ent ID# 429880
1999 Cadillac Seville


DTC U1064 Loss of Communications with DIM
Refer to Data Link Connector (DLC) Schematics

Circuit Description
The class 2 serial data line communicates information between modules. Each module connected to the serial data line is assigned a recognition code, or address. This code is used in order to identify which modules are communicating. Modules communicate with each other by periodically sending state of health (SOH) messages. When the ignition switch is in RUN, each module communicating on the serial data line sends a SOH message every 2 seconds. This ensures that the system is operating properly. When the dash integration module (DIM) stops communicating on the class 2 serial data line, the SOH that is normally sent on the serial data line every 2 seconds disappears. The module, which expects to receive that message, detects the absence of the message. The module in turn sets DTC U1064 associated with the loss of SOH of the DIM.

Conditions for Setting the DTC
The module does not receive a state of health (SOH) message back from the DIM. The module retries the request 3 times, and then sets DTC U1064.
This DTC only sets if U1300 or U1301 is not current.
Action Taken When the DTC Sets
DTC U1064 is stored in the module.
The module uses the default values for the initialization data.
This DTC does not cause driver warning message to appear.

Conditions for Clearing the DTC
This DTC clears (status changes from current to history) under any of the following conditions:
The module detects a state of health message from the DIM.
At each ignition cycle.
A history DTC clears after 50 consecutive ignition cycles if the conditions for setting the DTC are no longer present.
Current and history DTCs may be cleared using a scan tool.
Diagnostic Aids
DTC U1064 does not normally represent a failure within the module.
When loss of class 2 serial data communication DTCs (DTCs with the letter U as the prefix) are stored as history DTCs, know all possible serial data DTCs set in each module before diagnosing the serial data line.
If U1064 is stored in the module memory, inspect for the same DTC stored in other modules capable of storing this DTC.
If the DTC is a history DTC, the problem may be intermittent.
Old 07-30-2009, 05:31 AM
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thanks eric.... the code is AMP U1064 am i being stupid? what am i missing?
Old 07-30-2009, 09:09 AM
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Originally Posted by rickyd View Post
having trouble finding what AMP U 1064 code means.... 99 seville sts

If it is a history code, clear it and forget it
Probably just caused by removing battery power.

Old 07-30-2009, 09:34 AM
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If it persists, disconnect battery for 5 minutes then reconnect.
The Class2 data network sometimes needs to be REBOOTED.

Anytime that these cars are having weird electrical issues, the three things that you should do that cost NOTHING are:

1. check your battery terminals, clean them.

2. REBOOT the system by disconnecting the battery for 5 minutes which just happens by default if you do #1.

3. Find and clean all the grounds.

that code can kick in if power is disconnected, either by removal of the cables or a dirty/oxidized GROUND!


Last edited by stomper; 07-30-2009 at 09:36 AM.
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