Car is reading code IRC U1016

Tiny
ANONYMOUS
  • MEMBER
  • 2001 CADILLAC DEVILLE
  • 10,800 MILES
Car is reading code IRC U1016. Am also able to shift to drive from park without applying the brake. The car also has been starting and then stopping right away after the start. It will also stop sometimes during a turn. Is this an iginition switch problem?
Saturday, November 24th, 2012 AT 10:27 PM

4 Replies

Tiny
ASEMASTER6371
  • EXPERT
CIRCUIT DESCRIPTION
During normal vehicle operation modules connected to the class 2 serial data circuit monitor the class 2 serial data circuit for serial data communications. Operating information and commands are exchanged among the modules. When a module receives a critical operating parameter, the module records and identification number of the transmitting module for the purpose State of Health monitoring (Node Alive messages). A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. Once an identification number is learned by a module, it will monitor the class 2 serial data circuit for that module's Node Alive message. Each module on the class 2 serial data circuit is required to send a Node Alive message every 2 seconds. If no message is detected from a learned identification number for 5 seconds, a DTC U1xxx (where xxx is equal to the three digit identification number) is set.

CONDITIONS FOR RUNNING THE DTC

The following diagnostic trouble codes do not have a current status:
B1327
B1328
U1300
U1301
U1305
The vehicle power mode (ignition switch position) requires serial data communication to occur.

CONDITIONS FOR SETTING THE DTC
A message from a learned identification number has not been detected for the past five seconds.

CONDITIONS FOR CLEARING THE DTC

A current DTC will clear when a Node Alive message from the failed identification number is detected on the class 2 serial data circuit or at the end of the current ignition cycle.
A history DTC will clear upon receipt of a scan tool Clear DTCs command.

DIAGNOSTIC AIDS
When multiple Loss of Communication DTCs are set concurrently, the cause is likely to be two opens in the class 2 serial data circuit. Use the Control Module ID Number list in order to determine which modules are not communicating. Use the class 2 serial data circuit schematic in order to determine the location of the opens.

TEST DESCRIPTION

Steps 1-5

Steps 6-10

The numbers below refer to the step numbers on the diagnostic table.

The following modules have a single wire connection to the class 2 serial data circuit. An open in the single wire will prevent communications.

Audio Amplifier
Cellular Telephone Module W/UV8
Driver Door Module (DDM)
Driver Door Switch Assembly (DDSA)
Electronic Suspension Control (ESC)
Front Passenger Door Module (FPDM)
HVAC Control Module - Auxiliary
Left Middle Door Module (LMDM) W/V4U
Left Rear Door Module (LRDM)
Memory Seat Module (MSM)
Navigation Data Processor W/UY4
Radio W/UY4
Rear Integration Module (RIM)
Remote Control Door Lock Receiver (RCDLR)
Right Middle Door Module (RMDM) W/V4U
Right Rear Door Module (RRDM)
Steering Column Module W/N37
Theft Deterrent Control Module
Vehicle Interface Unit (VIU) W/UE1
Window Switch - Front Passenger W/armored car

The module which was not communicating due to an open in the class 2 serial data circuit may have set Loss of Communication DTCs for those modules that it was monitoring.

"For the description of RPO Code(s) shown in this article or any of the images therein, refer to the RPO Code List found at the Vehicle/Application and ID." See: Application and ID RPO Codes
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Saturday, November 24th, 2012 AT 10:57 PM
Tiny
GARYS712
  • MEMBER
So what does the code IRC U1016 mean then? Thanks!
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Sunday, November 25th, 2012 AT 1:11 AM
Tiny
ASEMASTER6371
  • EXPERT
It is a communication issue as stated above.

Roy
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Sunday, November 25th, 2012 AT 1:16 AM
Tiny
GARYS712
  • MEMBER
Thanks for the information. Just found a loose wire in the ignition and it works fine now.
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Sunday, November 25th, 2012 AT 1:22 AM

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