Review
The automatic lighting system is only active when the light switch is in the Auto position.
Refer to section 417-01 for a detailed description of system design and operation «External lighting fixtures» in the workshop manual.
Inspection and verification
1. Make sure the customer's complaint is valid.
2. Visually inspect for obvious electrical problems.
Mechanical factors | Electrical Factors |
3. If an obvious cause of a problem you identified or described by a customer is found, resolve it before proceeding to the next steps (if possible).
4. Use an approved diagnostic system or scan tool (tester), to retrieve all DTCs before referring to the symptom table or DTC index (DTC).
Since DTCs are stored in more than one module, a complete vehicle data readout is recommended.
Clear all DTCs after troubleshooting.
Symptom table
Symptom | Possible reasons | Actions |
Marker lamp (And) and headlight (s) do not work when automatic headlights are selected. | Check fuse (And) (see visual inspection). Check operation of light switches and wipers. Check the electrical circuit of the automatic headlights. Refer to the electrical manual. Check for DTCs that indicate a problem with the rain/light sensor or the LIN system. | |
The backlight of the automatic headlight switch does not work | Check fuse (And) (see visual inspection). Check the operation of the light switch. Check the automatic headlight relay circuit. Refer to the electrical manual. Check for DTCs indicating a problem with the automatic headlights. |
DTC index
NOTE: Universal Scan Tools cannot read the listed codes or can only read 5-digit codes. Match the 5 digits from the scan tool with the first 5 digits of the listed 7 digit code to identify the problem (the last 2 digits give additional information read by the diagnostic system approved by the manufacturer).
DTCs | Description | Possible reasons | Actions |
B1A9801 | LIN bus - electrical circuit No. 1 | LIN bus short to + battery or ground | Refer to the guided diagnostic program for this code on the approved diagnostic system. The LIN bus provides serial communications to the rain sensor, sunroof, optional seat memory modules, and DTC logging is controlled by the vehicle configuration file (CCF) (depending on installation). Repair is required only when one or more devices are installed and not working properly. See the description of the Lost Link condition at the beginning of this table. |
B1A9881 | LIN bus - electrical circuit No. 1 | Refer to the guided diagnostic program for this code on the approved diagnostic system. No repair required unless the customer complains about poor performance of the rain sensor, sunroof or seat memory. The LIN bus provides serial communications to the rain sensor, sunroof, optional seat memory modules, and DTC logging is controlled by the vehicle configuration file (CCF) (depending on installation). Repair is required only when one or more devices are installed and not working properly. See the description of the Lost Link condition at the beginning of this table. | |
B1A9883 | LIN bus - electrical circuit No. 1 | LIN bus checksum error | Refer to the guided diagnostic program for this code on the approved diagnostic system. The LIN bus provides serial communications to the rain sensor, sunroof, optional seat memory modules, and DTC logging is controlled by the vehicle configuration file (CCF) (depending on installation). Repair is required only when one or more devices are installed and not working properly. See the description of the Lost Link condition at the beginning of this table. |
B1B551C | Rain sensor module | The supply voltage of the rain sensor is not correct | Refer to the guided diagnostic program for this code on the approved diagnostic system. Refer to the electrical manuals and check the power supply to the sensor module from the CJB, repair if necessary. If power is present, no action is required, clear/ignore the DTC. |
B1B5546 | Rain sensor module | Rain Sensor Parameter/Calibration Memory Malfunction: Initialization Error - Optical Calibration Cannot Be Performed | Refer to the guided diagnostic program for this code on the approved diagnostic system. Check the cleanliness of the windshield in the sensor installation area. Check the correct installation of the sensor on the optical element and the tightness of the optical element to the windshield. Clear the DTC and recheck. If the DTC reoccurs, replace the rain/light sensor. |
B1B5549 | Rain sensor module | Internal electronic fault | Check the rain/light sensor module and circuit. Refer to the electrical manual. If a module is suspected, refer to the warranty policy and procedures manual. |
B1B5587 | Rain sensor module | No message | Refer to the guided diagnostic program for this code on the approved diagnostic system. The rain sensor is not installed on all modifications (custom installation). Fault logging is prohibited by the CCF file, but if the CCF file is configured incorrectly, a DTC may be logged by mistake. Repair is only required for vehicles with a sunroof. If necessary, see the description of the "Communication Lost" condition at the beginning of the section "Communication systems module". |
B1B5591 | Rain sensor module | Rain Sensor Module - The measured temperature is outside the normal operating range. | No action required, clear/ignore DTC. |
B1D3713 | Wiper switch wiring circuit | Wiper switch connection circuit - open circuit | Refer to the electrical manuals and check the switch circuit. Replace/repair as needed. |
B1C8612 | Auto headlight switch illumination relay output | Auto headlight switch backlight relay output circuit short to voltage | Refer to electrical manuals and check auto headlight switch backlight relay circuit (in the presence of). Replace/repair as needed. If there is no such device, check the vehicle configuration. Erase/ignore DTC. |
B1C8614 | Auto headlight switch illumination relay output | Auto headlight switch illumination relay output circuit short circuit to ground or open circuit | Refer to the guided diagnostic program for this code on the approved diagnostic system. Refer to the electrical manuals and check the fuse and output circuit of the auto headlight switch backlight relay (in the presence of). Replace/repair as needed. If there is no such device, check the vehicle configuration. Erase/ignore DTC. |
B1D4013 | Light switch connection circuit | Light switch connection circuit open circuit | Refer to the guided diagnostic program for this code on the approved diagnostic system. Refer to the electrical manuals and check the switch circuit. Replace/repair as needed. |
U1A1449 | CAN initialization failure | Internal electronic fault | Check the power circuits and grounds of the device. Refer to the electrical manual. Customize the module configuration (modules), using an approved diagnostic system. If a module is suspected, refer to the warranty policy and procedures manual. |
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