Diagnostic Starting Point - Lighting Systems
Begin the system diagnosis with the Diagnostic System Check - Vehicle in Vehicle DTC Information. The Diagnostic System Check - Vehicle will provide the following information
- The identification of the control modules which command the system
- The ability of the control modules to communicate through the serial data circuit
- The identification of any stored diagnostic trouble codes (DTCs) and their status
The Use of the Diagnostic System Check - Vehicle will identify the correct procedure for diagnosing the system and where the procedure is located.
Scan Tool Output Controls
| Scan Tool Output Control | Additional Menu Selection(s) | Description |
|---|---|---|
| Door Switch Backlight | Special Functions | The driver door module (DDM) illuminates the door switch incandescent lamps for 5 seconds when you select ON. |
| Exterior Courtesy Lamp | Special Functions | The DDM illuminates the exterior courtesy lamp for 5 seconds when you select ON and then fades to Off. |
| Lock Switch Indicator | Special Functions | The DDM illuminates the lock switch indicator LED for 5 seconds when you select ON. |
Driver Door Module (DDM) Output Controls
| Scan Tool Output Control | Additional Menu Selection(s) | Description |
|---|---|---|
| Display Test | Special Functions - IPC | The instrument panel cluster (IPC) activates the Display Test for 5 seconds when you select ON. The indicators should illuminate for 5 seconds. |
Instrument Panel Cluster (IPC) Output Controls
| Scan Tool Output Control | Additional Menu Selection(s) | Description |
|---|---|---|
| Headlamp Motor Test | Special Functions | The headlamp control module moves the headlamp leveling motors up for 5 seconds when you select UP, then centers the motors. The headlamp control module moves the headlamp leveling motors down for 5 seconds when you select DOWN, then centers the motors. |
Headlamp Control Module Output Controls
| Scan Tool Output Control | Additional Menu Selection(s) | Description |
|---|---|---|
| Door Switch Backlight | Special Functions | The left rear door module (LRDM) illuminates the door switch incandescent lamps for 5 seconds when you select ON. |
Left Rear Door Module (LRDM) Output Controls
| Scan Tool Output Control | Additional Menu Selection(s) | Description |
|---|---|---|
| Door Switch Backlight | Special Functions | The front passenger door module (PDM) illuminates the door switch incandescent lamps for 5 seconds when you select ON. |
| Exterior Courtesy Lamp | Special Functions | The PDM illuminates the exterior courtesy lamp for 5 seconds when you select ON and then fades to Off. |
| Lock Switch Indicator | Special Functions | The PDM illuminates the lock switch indicator LED for 5 seconds when you select ON. |
Passenger Door Module (PDM) Output Controls
| Scan Tool Output Control | Additional Menu Selection(s) | Description |
|---|---|---|
| Backup Lamp Relay | Special Functions - Output Control - Lighting | The rear integration module (RIM) activates the backup lamp relay for 5 seconds when you select ON. The backup lamps should illuminate for 5 seconds. |
| Courtesy Lamp w/Dimming | Special Functions - Output Control - Lighting | The RIM activates the courtesy lamps for 15 seconds when you select ON. The courtesy lamps will turn off through the theater dimming feature if you select OFF before the 15 second period has elapsed. |
| Courtesy Lamp w/o Dimming | Special Functions - Output Control - Lighting | The RIM activates the courtesy lamps for 5 seconds when you select ON. The courtesy lamps will turn off immediately if you select OFF before the 5 second period has elapsed. |
| Inadvertent Power Relay | Special Functions - Output Control - Lighting | The RIM deactivates the inadvertent power for 5 seconds when you select OFF. The interior lamps should be inoperative for 5 seconds. |
| LF Turn/Hazard Lamp | Special Functions - Output Control - Lighting | The RIM activates the left front turn/hazard lamps for 5 seconds when you select ON. The left front turn/hazard lamps should illuminate for 5 seconds. |
| LR Turn/Hazard Lamp | Special Functions - Output Control - Lighting | The RIM activates the left rear turn/hazard lamps for 5 seconds when you select ON. The left rear turn/hazard lamps should illuminate for 5 seconds. |
| Rear Fog Lamps | Special Functions - Output Control - Lighting | The RIM activates the rear fog lamp relay for 5 seconds when you select ON. The rear fog lamps should illuminate for 5 seconds. |
| RF Turn/Hazard Lamp | Special Functions - Output Control - Lighting | The RIM activates the right front turn/hazard lamps for 5 seconds when you select ON. The right front turn/hazard lamps should illuminate for 5 seconds. |
| RR Turn/Hazard Lamp | Special Functions - Output Control - Lighting | The RIM activates the right rear turn/hazard lamps for 5 seconds when you select ON. The right rear turn/hazard lamps should illuminate for 5 seconds. |
| Standing Lamp Relay | Special Functions - Output Control - Lighting | The RIM activates the standing lamp relay for 5 seconds when you select ON. The standing lamps should illuminate for 5 seconds. |
Rear Integration Module (RIM) Output Controls
| Scan Tool Output Control | Additional Menu Selection(s) | Description |
|---|---|---|
| Door Switch Backlight | Special Functions | The left rear door module (LRDM) illuminates the door switch incandescent lamps for 5 seconds when you select ON. |
Right Rear Door Module (RRDM) Output Controls
Scan Tool Data List
| Scan Tool Parameter | Data List | Units Displayed | Typical Data Value |
|---|---|---|---|
| Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed. | |||
| Ambient Light Status | Data Display-HVAC-Lighting Data | Dark/Light | Varies |
| Ambient Light Sensor | Data Display-HVAC-Open/Short Data | Volts | Varies |
| Dim Level Requested | Data Display-HVAC-Lighting Data | Percent | Varies |
| LCD Intensity | Data Display-HVAC-Lighting Data | Percent | Varies |
HVAC Control Module Data List
| Scan Tool Parameter | Data List | Units Displayed | Typical Data Value |
|---|---|---|---|
| Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed. | |||
| Accessory LED Duty Cycle | Data Display-Outputs | Percent | Varies |
| BPPS High During Learn | Data Display-BPP System Data | No/Yes | No |
| BPPS Learned Home Position | Data Display-BPP System Data | Volts | Varies |
| BPPS Low During Learn | Data Display-BPP System Data | No/Yes | No |
| BPPS Move During Learn | Data Display-BPP System Data | No/Yes | No |
| BPP Sensor | Data Display-BPP System Data | Counts | Varies |
| BPP Sensor Reference | Data Display-BPP System Data | Counts | Varies |
| BPPS Status | Data Display-BPP System Data | Unlearned/Learned/Invalid/Undecided | Learned |
| Calculated Brake Pedal Position | Data Display-BPP System Data | Counts | Varies |
| Courtesy Lamp Switch | Data Display-Inputs | On/Off | Off |
| Dimming Pot A/D | Data Display-Inputs | Counts | Varies |
| Front Fog Lamp Relay Status | Data Display-Outputs | On/Off | Off |
| Flash to Pass Switch | Data Display-Inputs | Inactive/Active | Inactive |
| Hazard Lamps | Data Display-Interior Lamps | On/Off | Off |
| Hazard Lamp Switch | Data Display-Inputs | Enabled/Disabled | Disabled |
| Headlamp Switch | Data Display-Inputs | On/Off | Off |
| Headlamp/Parklamp Off Switch | Data Display-Inputs | On/Off | Off |
| High Beam Select Switch | Data Display-Inputs | Inactive/Active | Inactive |
| High Beam Relay Status | Data Display-Outputs | On/Off | Off |
| Key Cylinder Halo Lamp | Data Display-Outputs | Percent | Varies |
| LED Dimming | Data Display-Outputs | Percent | Varies |
| Low Beam Relay Status | Data Display-Outputs | On/Off | Off |
| Incandescent Dimming | Data Display-Outputs | Percent | Varies |
| Learn In Progress | Data Display-BPP System Data | No/Yes | No |
| Lights On With Wipers | Data Display-Inputs | On/Off | Off |
| OFF LED Duty Cycle | Data Display-Outputs | Percent | Varies |
| Park Lamp Relay Status | Data Display-Outputs | On/Off | Off |
| Parking Brake Switch | Data Display-Inputs | Released/Applied | Released |
| Park Lamp Switch | Data Display-Inputs | On/Off | Off |
| Photocell State | Data Display-Exterior Lamps | Day/Night | Day |
| Smart Beam Status | Data Display-Outputs | Disabled/Enabled | Disabled |
| Start LED Duty Cycle | Data Display-Outputs | Percent | Varies |
| Stop Lamp Relay | Data Display-Outputs | Released/Applied | Released |
| Stop Lamp Status | Data Display-BPP System Data | Off/On | Off |
| Twilight Enable | Data Display-Exterior Lamps | Enabled/Disabled | Disabled |
Instrument Panel Module (IPM) Data List
| Scan Tool Parameter | Data List | Units Displayed | Typical Data Value |
|---|---|---|---|
| Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed. | |||
| Door Ajar Switch | Data | Door Closed/Door Ajar | Door Closed |
| Door Open Switch | Data | Closed/Open | Closed |
| Door Switch Backlight Command | Data | Percent | Varies |
| Exterior Courtesy Lamp Command | Data | Percent | Varies |
| Exterior Courtesy Lamp Status | Data | Off/On | Off |
| Lock Indicator Command | Data | Percent | Varies |
| Lock Switch Indicator Command | Data | Off/On | Off |
Driver Door Module (DDM) Data List
| Scan Tool Parameter | Data List | Units Displayed | Typical Data Value |
|---|---|---|---|
| Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed. | |||
| 8-Digit GM Part Number | ECU Identification Information | Number | Varies |
| Battery Voltage Signal | Data | 9-15 Volts | 12.8 Volts |
| Component Serial No. 13 | ECU Identification Information | Number | 13-16th Digit |
| Front Leveling Position | Data | Volts | Varies |
| Headlamp Leveling Mode | Data | Normal/Safe | Normal |
| High Beam Hdlp. Signal | Data | Inactive/Active | Inactive |
| Julian Date Of Build | ECU Identification Information | Number | Varies |
| Leveling Actuator Command | Data | Counts | Varies |
| Low Beam Hdlp. Signal | Data | Inactive/Active | Inactive |
| Position Sensor Reference | Data | Volts | Varies |
| Rear Leveling Position | Data | Volts | Varies |
| Year Model Built | ECU Identification Information | Number | Varies |
Headlamp Control Module Data List
| Scan Tool Parameter | Data List | Units Displayed | Typical Data Value |
|---|---|---|---|
| Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed. | |||
| Ambient Light Sensor | HUD Data | Night/Day | Day |
| Display Dimming | HUD Data | Percent | Varies |
| Display Dimming Signal | HUD Data | Volts | Varies |
Heads Up Display (HUD) Data List
| Scan Tool Parameter | Data List | Units Displayed | Typical Data Value |
|---|---|---|---|
| Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed. | |||
| Cage Backlight Dimming | IPC Data | Percent | Varies |
| Indicator Dimming | IPC Data | Percent | Varies |
| Pointer Dimming | IPC Data | Percent | Varies |
| LCD Dimming | IPC Data | Percent | Varies |
Instrument Panel Cluster (IPC) Data List
| Scan Tool Parameter | Data List | Units Displayed | Typical Data Value |
|---|---|---|---|
| Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed. | |||
| Door Ajar Switch | Data | Door Closed/Door Ajar | Door Closed |
| Door Open Switch | Data | Closed/Open | Closed |
| Door Switch Backlight Command | Data | Percent | Varies |
Left Rear Door Module (LRDM) Data List
| Scan Tool Parameter | Data List | Units Displayed | Typical Data Value |
|---|---|---|---|
| Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed. | |||
| Door Ajar Switch | Data | Door Closed/Door Ajar | Door Closed |
| Door Open Switch | Data | Closed/Open | Closed |
| Door Switch Backlight Command | Data | Percent | Varies |
| Exterior Courtesy Lamp Command | Data | Percent | Varies |
| Exterior Courtesy Lamp Status | Data | Off/On | Off |
| Lock Indicator Command | Data | Percent | Varies |
| Lock Switch Indicator Command | Data | Off/On | Off |
Passenger Door Module (PDM) Data List
| Scan Tool Parameter | Data List | Units Displayed | Typical Data Value |
|---|---|---|---|
| Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed. | |||
| Ambient Light Status | Lighting Data | Night/Day | Day |
| Backup Lamp Relay Cmd. | Lighting Data | Off/On | Off |
| BPP Circuit Signal | Inputs | Inactive/Active | Inactive |
| Courtesy Lamp PWM Cmd. | Lighting Data | Percent | Varies |
| Courtesy Lamp Dimming Status | Lighting Data | Off/On/Fade Off/Fade On | Off |
| Courtesy Lamp Status | Lighting Data | Invalid/Manual/Manual Defeat/Door Open/Door Closed/Exit/RFA/RFA Theft/SDM/Panic | Manual |
| Inadvertent Power Cmd. | Lighting Data | Inactive/Active | Inactive |
| Inadvertent Power Input | Inputs | Inactive/Active | Inactive |
| LF Turn/Hazard Lamp Command | Lighting Data | Off/On | Off |
| LR Turn/Hazard Lamp Command | Lighting Data | Off/On | Off |
| Rear Compartment Lid Ajar | Inputs | Closed/Ajar | Closed |
| Rear Compartment Lid Release Relay | Outputs | Off/On | Off |
| Rear Fog Lamp Relay Cmd. | Lighting Data | Off/On | Off |
| Reverse Switch | Inputs | Inactive/Active | Inactive |
| RF Turn/Hazard Lamp Command | Lighting Data | Off/On | Off |
| RR Turn/Hazard Lamp Command | Lighting Data | Off/On | Off |
| Standing Lamp Relay Cmd. | Lighting Data | Off/On | Off |
Rear Integration Module (RIM) Data List
| Scan Tool Parameter | Data List | Units Displayed | Typical Data Value |
|---|---|---|---|
| Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed. | |||
| Door Ajar Switch | Data | Door Closed/Door Ajar | Door Closed |
| Door Open Switch | Data | Closed/Open | Closed |
| Door Switch Backlight Command | Data | Percent | Varies |
Right Rear Door Module (RRDM) Data List
Scan Tool Data Definitions
See also:
• Diagnostic System Check - Vehicle