Contents Wiring diagrams Section: Exterior Lights All sections

Lighting Systems (General Diagnosis) Cadillac CTS I

Exterior Lights ~338 words

DIAGNOSTIC STARTING POINT - LIGHTING SYSTEMS

Begin the system diagnosis with the Diagnostic System Check - Lighting Systems . The Diagnostic System Check will provide the following information

  1. The identification of the control modules which command the system.
  2. The ability of the control modules to communicate through the serial data circuit.
  3. The identification of any stored diagnostic trouble codes (DTCs) and their status.

The use of the Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. 2: Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
  2. 4: DTCs from all of the modules listed must be retrieved.
  3. 5: The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
StepActionYesNo
1Install a scan tool. Does the scan tool power up?Go to Step 2Go to Scan Tool Does Not Power Up in Data Link Communications
2Turn ON the ignition, with the engine OFF. Attempt to establish communication with the following control module: Climate control panel (CCP) Dash integration module (DIM) Electronic brake control module (EBCM) Instrument panel cluster (IPC) Left headlamp leveling module with TR7 Rear integration module (RIM) Right headlamp leveling module with TR7 Transmission control module (TCM) Does the scan tool communicate with the CCP, EBCM, DIM, IPC, RIM and headlamp modules if equipped?Go to Step 3Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications
3IMPORTANT: The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode. Access the Class 2 Power Mode in the Diagnostic Circuit Check on the scan tool. Rotate the ignition switch through all positions while observing the ignition switch power mode parameter. Does the ignition switch parameter reading match the ignition switch position for all switch positions?Go to Step 4Go to Power Mode Mismatch in Body Control System
4Select each of the following control modules to display DTCs function on the scan tool. DIM EBCM IPC Lt. Headlamp Leveling Mod. RIM Rt. Headlamp Leveling Mod. TCM Does the scan tool display any DTCs?Go to Step 5Go to Symptoms - Lighting Systems
5Does the scan tool display any DTCs which begin with a "U"?Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link CommunicationsGo to Step 6
6Does the scan tool display DTC B1000, B1004, B1007, or B1009?Go to Diagnostic Trouble Code (DTC) List in Body Control SystemGo to Step 7
7Does the scan tool display DTC B1327 or B1328?Go to Diagnostic Trouble Code (DTC) List in Engine ElectricalGo to Diagnostic Trouble Code (DTC) List
IMPORTANT
The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode.

Diagnostic System Check - Lighting Systems

SCAN TOOL OUTPUT CONTROLS

Scan Tool Output ControlAdditional Menu Selection(s)Description
LCD IntensitySpecial Functions-Miscellaneous TestThe HVAC control module activates its LCD backlighting for 5 seconds when you select ON.
LED IntensitySpecial Functions-Miscellaneous TestThe HVAC control module activates its control button LED backlighting for 5 seconds when you select ON.

Climate Control Panel

Scan Tool Output ControlAdditional Menu Selection(s)Description
Daytime Running LampsSpecial Functions-Output ControlThe DIM activates the daytime running lamp input to the turn signal/hazard flasher module for 5 seconds when you select ON. The daytime running lamps should illuminate for 5 seconds.
Front Fog LampsSpecial Functions-Output ControlThe DIM activates the front FOG LP relay for 5 seconds when you select ON. The front fog lamps and front fog lamp indicator should illuminate for 5 seconds.
High Beam - Flash to PassSpecial Functions-Output ControlThe DIM activates the HI BEAM relay for 5 seconds when you select ON. The high beam headlamps should illuminate for 5 seconds.
High/Low Beam RelaySpecial Functions-Output ControlThe DIM activates either the LO BEAM relay or the HI BEAM relay for 5 seconds when you select ON, depending on the position of the headlamp dimmer switch. Either the low beam headlamps or the high beam headlamps should illuminate for 5 seconds.
Incandescent DimmingSpecial Functions-Output ControlThe DIM activates the incandescent backlighting lamps when you select ON. The incandescent backlighting lamps should illuminate for 5 seconds.
Lighting for TheftSpecial Functions-Output ControlThe DIM activates the hazard sense input to the turn/hazard/DRL module for 5 seconds when you select ON. The hazard lamps should illuminate for 5 seconds.
Parking Lamps RelaySpecial Functions-Output ControlThe DIM activates the park lamp relay for 5 seconds when you select ON. The park lamps should illuminate for 5 seconds.

Dash Integration Module

Scan Tool Output ControlAdditional Menu Selection(s)Description
Switch Dimming FeedSpecial Functions-Output Control-Miscellaneous TestsThe Driver Door Module illuminates the door switch incandescent lamps for 5 seconds when you select ON.

Driver Door Module

Scan Tool Output ControlAdditional Menu Selection(s)Description
Cluster DimmingSpecial Functions-Output ControlIncreases and decreases instrument cluster dimming.
Display TestSpecial Functions-Output ControlThe instrument panel cluster activates the Display Test for 5 seconds when you select ON. The indicators should illuminate for 5 seconds.

Instrument Panel Cluster

Scan Tool Output ControlAdditional Menu Selection(s)Description
Switch Dimming FeedSpecial Functions-Output Control-Miscellaneous TestsThe Left Rear Door Module illuminates the door switch incandescent lamps for 5 seconds when you select ON.

Left Rear Door Module

Scan Tool Output ControlAdditional Menu Selection(s)Description
Headlamp Motor TestSpecial Functions-Output ControlThe left headlamp leveling module moves the left headlamp leveling motor up for 5 seconds when you select UP, then centers the motor. The left headlamp leveling module moves the left headlamp leveling motor down for 5 seconds when you select DOWN, then centers the motor.

Lt. Headlamp Leveling Mod. (w/ TR7)

Scan Tool Output ControlAdditional Menu Selection(s)Description
Switch Dimming FeedSpecial Functions-Output Control-Miscellaneous TestsThe Passenger Door Module illuminates the door switch incandescent lamps for 5 seconds when you select ON.

Passenger Door Module

Scan Tool Output ControlAdditional Menu Selection(s)Description
Courtesy Lamp 1,2 w/dimSpecial Functions-Output ControlThe RIM activates the courtesy lamps for 5 seconds when you select ON. The courtesy lamps should illuminate for 5 seconds. The courtesy lamps will turn off through the theater dimming feature if you select OFF before the 5 second period has elapsed.
Courtesy Lamp 1,2 wo/dimSpecial Functions-Output ControlThe RIM activates the courtesy lamps for 5 seconds when you select ON. The courtesy lamps should illuminate for 5 seconds. The courtesy lamps will turn off immediately if you select OFF before the 5 second period has elapsed.
Inadvertent Power RelaySpecial Functions-Output ControlThe RIM deactivates the inadvertent power for 5 seconds when you select OFF. The interior lamps should be inoperative for 5 seconds.
Rear Fog Lamp RelaySpecial Functions-Output ControlThe RIM activates the rear fog lamp relay for 5 seconds when you select ON. The rear fog lamps should illuminate for 5 seconds.
Reverse Lamp RelaySpecial Functions-Output ControlThe RIM activates the reverse lamp relay for 5 seconds when you select ON. The backup lamps should illuminate for 5 seconds.

Rear Integration Module

Scan Tool Output ControlAdditional Menu Selection(s)Description
Switch Dimming FeedSpecial Functions-Output Control-Miscellaneous TestsThe Right Rear Door Module illuminates the door switch incandescent lamps for 5 seconds when you select ON.

Right Rear Door Module

Scan Tool Output ControlAdditional Menu Selection(s)Description
Headlamp Motor TestSpecial Functions-Output ControlThe right headlamp leveling module moves the right headlamp leveling motor up for 5 seconds when you select UP, then centers the motor. The right headlamp leveling module moves the right headlamp leveling motor down for 5 seconds when you select DOWN, then centers the motor.

Rt. Headlamp Leveling Mod. (w/ TR7)

SCAN TOOL DATA LIST

Scan Tool ParameterData ListUnits DisplayedTypical Data Value
Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed.
PhotocellData Display-Lighting DataVolts/CountsVaries
Photocell StatusData Display-Lighting DataDark/LightVaries
Dimming EnabledData Display-Lighting DataYes/NoVaries
Dim Level RequestedData Display-Lighting DataPercentVaries
LCD IntensityData Display-Lighting DataPercentVaries
LED IntensityData Display-Lighting DataPercentVaries

Climate Control Panel (CCP)

Scan Tool ParameterData ListUnits DisplayedTypical Data Value
Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed.
Control PowerOutputOn/OffOff
Courtesy Lamp SwitchInputsOn/OffOff
Daytime Running LampOutputsOn/OffOff
Dimming PotentiometerInputsVoltsVaries
Front Fog Lamp RelayOutputsOn/OffOff
Front Fog Lamp SwitchInputsIdle/ActiveIdle
Flash to Pass SwitchInputsOn/OffOff
Hazard Lamp SwitchInputsOn/OffOff
Head Lamp SwitchInputsOn/OffOff
High Beam - Flash to PaOutputsOn/OffOff
High Beam Switch/RelayInputsOn/OffOff
High/Low Beam RelayOutputsOn/OffOff
Incandescent DimmingOutputsPercentVaries
Lights On With WipersInputsOn/OffOff
Rear Fog Lamp SwitchInputsIdle/ActiveIdle
Park Lamp RelayOutputsOn/OffOff
Park Lamp SwitchInputsOn/OffOff
Theft LightingOutputsOn/OffOff
Twilight SwitchInputsOn/OffOff

Dash Integration Module (DIM)

Scan Tool ParameterData ListUnits DisplayedTypical Data Value
Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed.
Driver Door Jamb Sw.InputsOn/OffOff
Switch DimmingOutputsActive/InactiveActive

Driver Door Module (DDM)

Scan Tool ParameterData ListUnits DisplayedTypical Data Value
Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed.
BPP Sensor CalibrationSpecial Functions
BPP Sensor A/D ConversiBAS System DataVoltsVaries
BPP Sensor DisplacementBAS System DataPercentVaries
BPPS Learned Home PositBAS System DataVoltsVaries
BPP Sensor Power SupplyBAS System DataVoltsVaries
Stop Lamp StatusBAS System DataValid/Not ValidValid
Stop Lamp SwitchBAS System DataApplied/ReleasedReleased

Electronic Brake Control Module (EBCM)

Scan Tool ParameterData ListUnits DisplayedTypical Data Value
Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed.
Park Brake SwitchInputsOn/OffOff
Left Turn SignalInputsOn/OffOff
Right Turn SignalInputsOn/OffOff

Instrument Panel Cluster (IPC)

Scan Tool ParameterData ListUnits DisplayedTypical Data Value
Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed.
Left Rear Door Jamb Sw.InputsOn/OffOff
Switch DimmingOutputsActive/InactiveInactive

Left Rear Door Module (LRDM)

Scan Tool ParameterData ListUnits DisplayedTypical Data Value
Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed.
Calibrate ModuleSpecial Functions
Low Beam InputDataVolts0-25V
Front SensorDataPercent0-100%
Rear SensorDataPercent0-100%
Stepper Motor PositionDataCounts0-255

Lt. Headlamp Leveling Mod.

Scan Tool ParameterData ListUnits DisplayedTypical Data Value
Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed.
Pass. Door Jamb Sw.InputsOn/OffOff
Switch DimmingOutputsActive/InactiveInactive

Passenger Door Module (PDM)

Scan Tool ParameterData ListUnits DisplayedTypical Data Value
Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed.
TCC Brake SwitchTCC DataOpen/ClosedClosed
IMSTransmission DataPark/Reverse/ Neutral/Drive5/Drive4/ Drive3/Drive2/ Drive1Varies

Powertrain

Scan Tool ParameterData ListUnits DisplayedTypical Data Value
Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed.
Inadvertent Power InputInputsActive/InactiveInactive
Inadvertent Power RelayOutputsOn/OffOn
Overhead Lamps OutputOutputsOn/OffOff
Position Lamp Relay (ExOutputsOn/OffOff
Rear Fog Lamp RelayOutputsOn/OffOff
Reverse Lamp RelayOutputsOn/OffOff
Trunk Ajar SwitchInputsClosed/AjarClosed

Rear Integration Module (RIM)

Scan Tool ParameterData ListUnits DisplayedTypical Data Value
Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed.
Rt. Rear Door Jamb Sw.InputsOn/OffOff
Switch DimmingOutputsActive/InactiveActive

Right Rear Door Module (RRDM)

Scan Tool ParameterData ListUnits DisplayedTypical Data Value
Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. All lighting turned OFF. All doors closed.
Calibrate ModuleSpecial Functions
Low Beam InputDataVolts0-25V
Front SensorDataPercent0-100%
Rear SensorDataPercent0-100%
Stepper Motor PositionDataCounts0-255

Rt. Headlamp Leveling Mod.

DIAGNOSTIC TROUBLE CODE (DTC) LIST

DTCDiagnostic ProcedureModule(s)
B2556DTC B2556DIM
B2575DTC B2575HLM
B2646DTC B2646CCP
B3410DTC B3410HLM
B3420DTC B3420HLM
B3903DTC B3903EBCM
C0278DTC C0278EBCM
C0282DTC C0282EBCM
C0283DTC C0283EBCM
C0284DTC C0284EBCM
C0880DTC C0880EBCM
P0572DTC P0572TCM
P0573DTC P0573TCM

Diagnostic Trouble Code (DTC) List