Tail lights, parking lights, license plate lights
1. Make sure the customer's complaint is valid.
2. Visually inspect for obvious electrical problems.
Mechanical factors | Electrical Factors |
3. If there is an obvious cause for the problem you identified or the customer described, fix 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 |
Rear light not working (And) /flashlight (And) license plate lights | Check the condition of the lamp and fuse (see visual inspection table). Check the circuits for the rear/license plate lights. Check the operation of the light switch. Refer to the electrical manual. Check for DTCs that indicate a malfunction in the tail/license plate lights circuits. | |
Dim rear light (to her) /lantern (to her) license plate lights | Check the condition and power of the lamp. Check the circuits for the rear/license plate lights. Check the operation of the light switch. refer to the electrical manual. | |
Back light (And) /flashlight (And) license plate light stays on | Check the circuits for the rear/license plate lights. Check the operation of the light switch. Refer to the electrical manual. Check for DTCs that indicate a malfunction in the tail/license plate lights circuits. | |
Back light (And) /flashlight (And) The license plate light does not work when automatic headlights are selected. | Check fuse (And) (see visual inspection). Check the operation of the light switch. 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. |
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 unit, repair if necessary. If power is present, no action is required, clear/ignore the DTC. |
B1B5546 | Rain sensor module | Rain sensor parameter/calibration memory failure: Initialization error - optical calibration not possible | 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). Failure logging is prohibited by the CCF file, but misconfiguration of the CCF file can log a DTC by mistake. Repair is required only for cars 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. |
B1C6012 | Position Lamp Relay Output Circuit | A lamp failure can also cause DTC B1B0187 to be stored in the communication network module and DTC C1A5564 to be stored in the parking brake module. A malfunction in this circuit that sets DTC B1C6012 can also cause automatic transmission shifting problems. Check if the tail/brake lamps are of the correct type, installed correctly, or for faults, including a short circuit in the lamp filaments. Refer to the electrical manuals and check the parking light relay output circuit. Replace/repair as needed. | |
B1C6014 | Position Lamp Relay Output Circuit | Refer to the guided diagnostic program for this code on the approved diagnostic system. | |
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 there is any doubt about the functionality of the module, refer to the Warranty Policy and Procedures Manual. |
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