U2152

DTC U2152 Bus Request Line Short to Ground:

CIRCUIT DESCRIPTION
When the Navigation Display Module is running through System Inspection Mode, it tests the Chip Bus Request signal. The Navigation Display Module does this by sending a signal from pin 16 of connector C2 to pin 1 of the Navigation Data Processor connector C1 on circuit 1692.

CONDITIONS FOR RUNNING THE DTC
Navigation Display Module is running through System Inspection Mode.

CONDITIONS FOR SETTING THE DTC
^ An invalid Chip Bus Request signal from the Navigation Data Processor is detected during System Inspection Mode.
^ An invalid Chip Bus Request signal from the Navigation Display Module is detected during System Inspection Mode.
^ The Chip Bus Request circuit 1692 open or shorted to ground.

ACTION TAKEN WHEN THE DTC SETS
^ Audio related operations will slow down if DTC was set due to an invalid Chip Bus Request signal from the Navigation Data Processor.
^ Navigation operation will slow down if DTC was set due to an invalid Chip Bus Request signal from the Navigation Display Module.
^ All operations will slow down if DTC was set due to a short to ground condition on the Chip Bus Request circuit.
^ This failure will have no effect outside the Navigation System.

CONDITIONS FOR CLEARING THE MIL/DTC
^ A current DTC will clear when the Navigation Display Module does not detect the failure during the last execution of the System Inspection Mode. A history DTC will clear using a scan tool.

DIAGNOSTIC AIDS
^ An intermittent may be caused by the following:
- Mis-routed harness
- Rubbed through wire insulation
- Broken wire inside the insulation
^ Cycle the Ignition Switch even after a successful inspection with a scan tool so initialization will occur.
^ DTC U2152 will not set if DTC B1328, DTC B1327 or DTC U2150 is current.

TEST DESCRIPTION
The number(s) below refer to the step number(s) on the diagnostic table.
1. Determines if the malfunction is present.
2. Checks circuit 1692 for a short to B+ condition.
3. Checks circuit 1692 for a short to ground condition.
5. Determines if the malfunction is due to an internal fault in the Navigation Display Module or an open condition in circuit 1692.