B2422

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

Schematic:

CIRCUIT DESCRIPTION
The Instrument Panel Integration Module (IPM) receives an input from the IP dimmer switch in the headlamp switch. The IPM supplies the ground for the switch through the sensor return. The resistance of the IP dimmer switch varies between 0 Ohm and 40 k Ohms as the switch is operated. As the resistance of the IP dimmer switch varies, the voltage input to the IPM changes. The IPM determines the level of dimming for the switch backlighting and VF displays. The IPM then sends a message via the class 2 serial data line to the Dash Integration Module (DIM), the Driver Door Module (DDM), the Instrument Cluster (IPC), the radio (IRC), and the cellular Telephone Docking Station (PHN) indicating level of dimming for the switch backlighting and VF displays.

CONDITIONS FOR SETTING THE DTC
The IPM will set the DTC B2422 any time it detects that the IP dimmer switch input voltage is out of range.

SPECIFICATION
Normal switch input voltage: 0.33-4.70 V

ACTION TAKEN WHEN THE DTC SETS
The IPM will set the dimming level to maximum brightness.

CONDITIONS FOR CLEARING THE DTC
^ The IPM sees that the IP dimmer switch input voltage is within the valid range.
^ Use the On-Boards clearing DTCs feature.
^ Use a scan tool.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table:
1. Perform the Lighting Systems Diagnostic System Check before continuing with the diagnosis of this DTC.
2. If DTC B2420 is also set, the concern is with the common reference wiring to the twilight delay switch and the IP dimmer switch.
3. Checks for proper reference resistance of the twilight delay switch.
4. Checks for an open in CKT 61 (YEL).
5. Checks for a short to ground in CKT 1688 (LT BLU/BLK).
6. Checks for an open in CKT 1688 (LT BLU/BLK).
7. Checks if the value that the Instrument Panel Integration Module (IPM) is reading from the IP dimmer switch is too high.
8. Checks if the value that the Instrument Panel Integration Module (IPM) is reading from the IP dimmer switch is too low.
9. Checks for proper resistance with the IP dimmer switch set to the maximum position.
10. Checks for an open in CKT 44 (DK GRN).
11. Checks for proper resistance with the IP dimmer switch set to the minimum position.
12. Checks for a short to ground in CKT 44 (DK GRN).
14. Checks if the DTC is still set.
21. Clear all DTCs after the repair procedure is complete.