B1983

CIRCUIT DESCRIPTION
The DIM has a designated circuit for monitoring vehicle system voltage. Also, other modules monitor system voltage. The DIM sends a system voltage message to other modules that do not monitor system voltage via Class 2 message. When the DIM sets B1390, the system voltage message sent to the other modules will default to 12.9 Volts.

CONDITIONS FOR RUNNING THE DTC
This DTC shall run only if the DIM has power, ground and the ignition is not in START mode. This DTC shall execute regardless of the battery voltage, except when the DTC B1390 is set current.

CONDITIONS FOR SETTING THE DTC
^ This DTC shall be set as current when the voltage falls below 9.0 volts for 1.2 seconds.
^ When the vehicle exits START the DIM shall delay checking the voltage for 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ A message shall be sent out on the class 2 lines to notify all other modules of low battery voltage.
^ The modules disable the setting of U codes and other DTCs.

CONDITIONS FOR CLEARING THE DTC
^ The DTC will clear current status when the voltage is less than 15.5 volts for 1.2 seconds.
^ A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.
^ Use the ON-Board clearing DTCs feature.
^ Use a scan tool.

TEST DESCRIPTION

Steps 1-11:

The numbers below refer to the step numbers on the diagnostic table.
3. Tests for the proper voltage at battery positive voltage sense circuit of the DIM, if voltage is not within the proper operating range, the voltage sense circuit needs to be tested.
4. Tests the ground sense circuit of the DIM.
5. Tests for the proper voltage at any other module setting the DTC B1327. If voltage is not within the proper operating range, the battery positive voltage and ground circuits of the module needs to be tested.