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Contents Wiring diagrams Section: Exterior Lights All sections

Lighting System - DTC b0655 to DTC B388D Cadillac ATS I

Exterior Lights ~24759 words

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Center High Mounted Stop Lamp ControlB3884 0211B0655 5A
Center High Mounted Stop Lamp Ground1
1. Stop Lamps Malfunction

Circuit/System Description

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5 V reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the right and left stop lamp control circuits, engine control module (ECM), center high mounted stop lamp control circuit, and trailer lighting control module.

Conditions for Running the DTC

  1. Battery voltage must be between 9-16 V.
  2. Brakes APPLIED.

Conditions for Setting the DTC

The trailer lighting control module receives a serial data message from the BCM that the brakes have been applied, but the trailer lighting control module does not detect voltage on the center high mounted stop lamp control circuit.

Actions Taken When the DTC Sets

The trailer lighting control module will not illuminate the trailer stop lamps.

Conditions for Clearing the DTC

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

  1. «Trailer Connector/Provision Schematics»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-wiring-schematics-and-wiring-harness-routing-diagrams)
  2. «Exterior Lights Schematics»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

  1. Ignition OFF, exterior lamps OFF, disconnect the harness connectors at the following components. E6 Center High Mounted Stop Lamp K68 Trailer Lighting Control Module
  2. Connect a test lamp between the control circuit terminal 14 and ground, ignition ON.
  3. Verify the test lamp turns ON and OFF when commanding the Center Brake Lamp ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  4. Ignition OFF.
  5. Connect a test lamp between the appropriate control circuit terminal listed below and ground, ignition ON. Terminal A - sedan Terminal 1 - coupe
  6. Verify the test lamp turns ON and OFF when commanding the Center Brake Lamp ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  7. Ignition OFF, connect the harness connector at the E6 Center High Mounted Stop Lamp, ignition ON.
  8. Verify the center high mounted stop lamp turns ON and OFF when commanding the Center Brake Lamp ON and OFF with a scan tool. If the center high mounted stop lamp is always OFF Test or replace the E6 Center High Mounted Stop Lamp. If the center high mounted stop lamp turns ON and OFF
  9. Test or replace the K68 Trailer Lighting Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  1. «High Mount Stop Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or trailer lighting control module replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Instrument Panel Dimmer Switch B+ ReferenceB1395 03, B3600 03B1395 03, B3600 03B1395 07, B3600 07
Instrument Panel Dimmer Switch SignalB1395 03, B3600 03B1395 03, B3600 03B1395 07, B3600 07
Instrument Panel Dimmer Switch Low Reference111
1. Interior Backlighting Malfunction

The instrument panel dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The instrument panel dimmer switch provides a voltage signal to the body control module (BCM) that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The BCM provides a low reference, signal, and B+ voltage reference to the instrument panel dimmer switch. When the instrument panel dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the instrument panel dimmer switch through the instrument panel dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies a pulse width modulated (PWM) voltage through the LED dimming 1 and dimming 2 control circuits illuminating the interior backlighting to the requested level of brightness.

  1. Battery voltage must be between 9-16 V.
  2. Park Lamps ON.

DTC B1395 03

  1. The BCM detects a short to ground or an open/high resistance in the instrument panel dimmer switch B+ reference circuit.
  2. The BCM detects a short to ground or an open/high resistance in the instrument panel dimmer switch signal circuit.

DTC B1395 07

  1. The BCM detects a short to voltage in the instrument panel dimmer switch B+ reference circuit.
  2. The BCM detects a short to voltage in the instrument panel dimmer switch signal circuit.

The BCM will not dim any interior backlighting. All interior backlighting will default to the FULL bright.

  1. The condition responsible for setting the DTC no longer exists.
  2. Disconnect the negative battery cable for 30 seconds.
  3. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Diagnostic Aids

When a short to ground condition exists, the BCM goes into safe mode. The DTC will clear in most cases without removing the negative battery cable, but in order to restore the BCM to normal operating conditions the negative battery cable must be removed. The B+ reference circuit under normal operating conditions will illuminate a test lamp. When the BCM is in safe mode, a test lamp will no longer illuminate but the DTC will clear and the backlighting will dim normally.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S36 Instrument Panel Dimmer Switch, ignition ON.
  2. Test for B+ between the B+ circuit terminal 6 and ground. If less than B+ Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If B+
  3. Verify a test lamp illuminates between the B+ circuit terminal 6 and the low reference circuit terminal 1. If the test lamp does not illuminate Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the low reference circuit terminal 1 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp illuminates
  4. Verify a test lamp does not illuminate between the B+ circuit terminal 6 and the signal circuit terminal 2. If the test lamp illuminates Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If the test lamp does not illuminate
  5. Test for B+ between the B+ circuit terminal 6 and the signal circuit terminal 2. If less than B+ Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the signal circuit terminal 2 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If B+
  6. Test or replace the S36 Instrument Panel Dimmer Switch.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Interior Lamp and Multifunction Switch Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
LIN Serial Data - Left Headlamp Leveling ActuatorU1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05
LIN Serial Data - Right Headlamp Leveling ActuatorU1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05
Headlamp Control Module B+ Fuse (F29 UA)U0181 00U0181 00
Headlamp Leveling Actuator - Left B+ Fuse (F63 UA)U1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05
Headlamp Leveling Actuator - Right B+ Fuse (F63 UA)U1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05
Headlamp Control Module Ground1
Headlamp Assembly - Left Ground1
Headlamp Assembly - Right Ground1
1. Adaptive Forward Lighting Malfunction

Battery voltage is applied to the headlamp control module at all times. The headlamp control module has a normal operational voltage range of about 12.5-16 V and is only fully functional with the ignition switch is in the RUN position and the headlamp switch in the AUTOMATIC LIGHT position. The communications enable signal from the body control module (BCM) wakes the headlamp control module microprocessor. The headlamp control module receives serial data messages from the engine control module (ECM), transmission control module (TCM), electronic brake control module (EBCM), and BCM with information regarding power mode, speed, steering angle, transmission gear selection, and headlamp switch status. The headlamp control module calculates the headlamp angle and sends commands to the left and right adaptive forward lighting system headlamp actuators. The headlamp actuators drive the headlamps to the position commanded by the headlamp control module. The headlamp control module monitors the headlamp actuator motor control circuits for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory and the driver will be notified with a message displayed over the driver information center located on the instrument cluster.

  1. Battery voltage must be between 9-16 V.
  2. Ignition ON.
  3. Headlamps ON.

DTC B1461 00

The headlamp control module detects an internal malfunction in the left headlamp adaptive actuator.

DTC B1462 00

The headlamp control module detects an internal malfunction in the right headlamp adaptive actuator.

  1. When DTC B1461 or DTC B1462 sets, the headlamp control module will attempt to return the lamps to a nominal position and disable all requests to all headlamp actuators.
  2. The instrument cluster will display AFL Malfunction - Contact Service.
  3. On vehicles equipped with both AFL and headlamp leveling, the headlamp leveling system will be disabled.
  1. The condition responsible for setting the DTC no longer exists and the ignition is cycled.
  2. A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate E13 Headlamp Assembly. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 15 ohms between the ground circuit terminal 7 and ground. If 15 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 15 ohms
  3. Ignition ON.
  4. Verify a test lamp illuminates between the B+ circuit terminal 8 and ground. If the test lamp does not illuminate Ignition OFF, disconnect the X1 harness connector at the X50A Fuse Block - Underhood. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the X50A Fuse Block - Underhood. If the test lamp illuminates
  5. Test or replace the K26 Headlamp Control Module.
  6. Ignition ON.
  7. Verify the appropriate headlamp operates to the LEFT and RIGHT positions when commanding the appropriate Headlamp Horizontal Motor LEFT and RIGHT with a scan tool. If the headlamp does not operate LEFT and RIGHT Test or replace the E13 Headlamp Assembly. If the headlamp operates LEFT and RIGHT
  8. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Headlamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Front Compartment Fuse Block Housing Replacement»(/cadillac/ats/i-2012-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  3. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Headlamp Control Module replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Courtesy Lamps Control - Terminal 2 X7B1480 0211
Instrument Panel Compartment Lamp Ground1
Dome/Reading Lamps - Left Front Ground1
Dome/Reading Lamps - Left Rear Ground1
Dome/Reading Lamps - Right Front Ground1
Dome/Reading Lamps - Right Rear Ground1
Sunshade Mirror Lamp - Left Ground1
Sunshade Mirror Lamp - Right Ground1
1. Courtesy Lamps Malfunction

The body control module (BCM) supplies battery voltage to the front and rear reading lamps, left and right sunshade lamps, center console compartment lamp, and instrument panel compartment lamp via the courtesy lamp control circuit. When the instrument panel compartment, center console armrest, or a sunshade mirror is opened, the switch contacts close allowing battery voltage to flow illuminating the respective lamps. The front and rear reading lamps are controlled by individual switches that are activated by the occupants when additional cabin lighting is required. In the event that any of these courtesy lamps were to remain illuminated for more than 10 minutes with the ignition switch in the OFF position, the BCM will deactivate the courtesy lamp control circuit to prevent total battery discharge.

Battery voltage must be between 9-16 V.

The BCM detects a short to ground in the courtesy lamps control circuit terminal 2 X7.

The BCM will disable the circuit and all lamps controlled by the courtesy lamps control circuit will be inoperative.

  1. The condition responsible for setting the DTC no longer exists.
  2. Disconnect the negative battery cable for 30 seconds.
  3. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

  1. «Interior Lights Schematics»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-schematic-wiring-diagrams)
  2. «Body Control System Schematics»(/cadillac/ats/i-2012-2014/remont/communication-devices/#data-communication-system)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, exterior lamps OFF, disconnect the harness connectors at the components listed below. E27 Instrument Panel Compartment Lamp A31L Sunshade Mirror Lamp - Left A31R Sunshade Mirror Lamp - Right E37LF Dome/Reading Lamps - Left Front E37RF Dome/Reading Lamps - Right Front E37LR Dome/Reading Lamps - Left Rear E37RR Dome/Reading Lamps - Right Rear
  2. Connect a test lamp between the appropriate control circuit terminal listed below and ground. E27 Instrument Panel Compartment Lamp - terminal 1 A31L Sunshade Mirror Lamp - Left terminal A A31R Sunshade Mirror Lamp - Right terminal A E37LF Dome/Reading Lamps - Left Front terminal 1 E37RF Dome/Reading Lamps - Right Front terminal 1 E37LR Dome/Reading Lamps - Left Rear terminal A E37RR Dome/Reading Lamps - Right Rear terminal A
  3. Verify the test lamp turns ON and OFF when commanding the Inadvertent Load ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X7 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Ignition OFF, disconnect the X7 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  4. Test or replace the appropriate courtesy lamp.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Instrument Panel Compartment Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Sunshade Illuminated Mirror Lamp Lens Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  3. «Roof Rail Rear Seat Position Reading and Courtesy Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  4. «Center Reading and Courtesy Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  5. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Rear Fog Lamp Switch SignalB3588 0011
Rear Fog Lamp ControlB2540 02B2540 041
Rear Fog Lamp Ground1
Turn Signal/Multifunction Switch Ground1
1. Rear Fog Lamp Malfunction

The rear fog lamp switch signal circuit is grounded momentarily by pressing the rear fog lamp switch. The body control module (BCM) responds to the rear fog lamp request by applying voltage to the rear fog lamp control circuit which illuminates the rear fog lamp.

  1. Battery voltage must be between 9-16 V.
  2. Rear fog lamp ON.

DTC B2540 02

The BCM detects a short to ground in the rear fog lamp control circuit.

DTC B2540 04

The BCM detects an open/high resistance in the rear fog lamp control circuit.

The rear fog lamp will not operate when the park lamps are ON and the rear fog lamp switch is active.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the E29R Fog Lamp - Rear.
  2. Test for less than 5 ohms between the ground circuit terminal 2 and ground. If 5 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 3 and ground, ignition ON.
  4. Verify the test lamp turns ON and OFF when commanding the Rear Fog Lamp ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X5 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Ignition OFF, disconnect the X5 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  5. Test or replace the E29R Fog Lamp - Rear.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Backup Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
F4UA (BCM 6) Fuse B+11
Backup Lamps ControlB2545 02B2545 01, B2545 041
Backup Lamp Ground - Left1
Backup Lamp Ground - Right1
1. Backup Lamps Malfunction

Automatic Transmission

With the engine running and the transmission in the reverse position, the transmission control module (TCM) sends a serial data message to the body control module (BCM). The message indicates that the gear selector is in the reverse position. The BCM applies battery voltage to the backup lamps control circuit illuminating the backup lamps. Once the driver moves the gear selector out of the reverse position, a message is sent by the TCM via serial data requesting the BCM to remove battery voltage from the backup lamps control circuit. The engine must be running for the backup lamps to operate.

Manual Transmission

The engine control module (ECM) provides a signal circuit to the backup lamp switch which is permanently grounded. With the engine running and the transmission in the reverse position, the backup lamp switch signal circuit is pulled low and the ECM responds by sending a serial data message to the body control module (BCM). The message indicates that the gear selector is in the reverse position. The BCM applies battery voltage to the backup lamps control circuit illuminating the backup lamps. Once the driver moves the gear selector out of the reverse position, a message is sent by the ECM via serial data requesting the BCM to remove battery voltage from the backup lamps control circuit. The engine must be running for the backup lamps to operate.

  1. Battery voltage must be between 9-16 V.
  2. Engine RUNNING.
  3. Transmission placed in REVERSE gear.

DTC B2545 01 and B2545 04

The BCM detects an open/high resistance in the backup lamps control circuit.

DTC B2545 02

The BCM detects a short to ground in the backup lamps control circuit.

The backup lamps will not operate.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

  1. «Exterior Lights Schematics»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-schematic-wiring-diagrams)
  2. «Body Control System Schematics»(/cadillac/ats/i-2012-2014/remont/communication-devices/#data-communication-system)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate E5 backup lamp.
  2. Test for less than 5 ohms between the ground circuit terminal 2 and ground. If 5 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 1 and ground, ignition ON.
  4. Verify the test lamp turns ON and OFF when commanding the Backup Lamps ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X7 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Ignition OFF, disconnect the X7 harness connector at the K9 body control module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the appropriate E5 backup lamp.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Backup Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Courtesy Lamps Control - Terminal 23 X1B255D 02B255D 04B255D 01
Dome/Reading Lamps - Overhead Console Ground1
Dome/Reading Lamps - Left Front Ground1
Dome/Reading Lamps - Left Rear Ground1
Dome/Reading Lamps - Right Front Ground1
Dome/Reading Lamps - Right Rear Ground1
Instrument Panel Courtesy Lamp - Left Ground1
Instrument Panel Courtesy Lamp - Right Ground1
Instrument Cluster Accent Lamp - Left Ground1
Instrument Cluster Accent Lamp - Right Ground1
Instrument Cluster Accent Lamp - Top Ground1
1. Interior Accent Lighting Malfunction

The body control module (BCM) supplies battery voltage to accent lighting lamps via the accent lamp control circuit. When a door is opened the BCM applies battery voltage to the accent lamp control circuit illuminating all of the accent lighting. The accent lighting will remain illuminated until all doors are closed and the ignition is OFF. The accent lighting remains illuminated with the ignition ON.

Battery voltage must be between 9-16 V.

DTC B255D 01

The BCM detects a short to voltage in the courtesy lamps control circuit terminal 23 X1.

DTC B255D 02

The BCM detects a short to ground in the courtesy lamps control circuit terminal 23 X1.

DTC B255D 04

The BCM detects an open/high resistance in the courtesy lamps control circuit terminal 23 X1.

The BCM will disable the courtesy lamps control circuit terminal 23 X1.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, all doors closed, all accessories OFF, disconnect the harness connector at the inoperative component. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 ohms between the appropriate ground circuit terminal and ground. If 10 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 10 ohms
  3. Connect a test lamp between the appropriate control circuit terminal and ground.
  4. Verify the test lamp turns ON and OFF when commanding the Accent Lighting ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X1 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Ignition OFF, disconnect the X1 harness connector at the K9 body control module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the appropriate courtesy lamp.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Center Courtesy Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Accent Lamp Control - Terminal 22 X7B255F 02B255F 041
Accent Lamp Control - Terminal 23 X1111
Accent Lamp - Driver Door Ground1
Accent Lamp - Passenger Door Ground1
Accent Lamp - Center Console Armrest Left Ground1
Accent Lamp - Center Console Armrest Right Ground1
Accent Lamp - Center Console Armrest Left Rear Ground1
Accent Lamp - Center Console Armrest Right Rear Ground1
Accent Lamp - Right Rear Door Ground1
Accent Lamp - Left Rear Door Ground1
Flood Lamp - Driver Door Pull Handle Ground1
Flood Lamp - Driver Door Pocket Ground1
Flood Lamp - Passenger Door Handle Ground1
Flood Lamp - Passenger Door Pull Handle Ground1
Flood Lamp - Passenger Door Pocket Ground1
Flood Lamp - Left Rear Door Handle Ground1
Flood Lamp - Left Rear Door Pull Handle Ground1
Flood Lamp - Left Rear Door Pocket Ground1
Flood Lamp - Right Rear Door Handle Ground1
Flood Lamp - Right Rear Door Pull Handle Ground1
Flood Lamp - Right Rear Door Pocket Ground1
1. Interior Accent Lighting Malfunction

The body control module (BCM) supplies battery voltage to accent lighting lamps via the accent lamp control circuit. When a door is opened the BCM applies battery voltage to the accent lamp control circuit illuminating all of the accent lighting. The accent lighting will remain illuminated until all doors are closed and the ignition is OFF. The accent lighting remains illuminated with the ignition ON.

Battery voltage must be between 9-16 V.

DTC B255F 02

The BCM detects a short to ground in the accent lamp control circuit terminal 22 X7

DTC B255F 04

The BCM detects an open/high resistance in the accent lamp control circuit terminal 22 X7

The BCM will disable the accent lamp control circuit.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

  1. «Interior Lights Dimming Schematics»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-schematic-wiring-diagrams)
  2. «Body Control System Schematics»(/cadillac/ats/i-2012-2014/remont/communication-devices/#data-communication-system)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the component with the inoperative LED backlighting.
  2. Connect a test lamp between the appropriate control circuit terminal and ground.
  3. Verify the test lamp turns ON and OFF when commanding the Accent Lighting ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X7 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Ignition OFF, disconnect the X7 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  4. Test or replace the appropriate accent/flood lamp.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Center Courtesy Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Front Side Door Inside Handle Illumination Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  3. «Rear Side Door Inside Handle Illumination Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  4. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
F6RA (BCM 4) Fuse B+11
Rear Compartment Courtesy Lamps ControlB2570 02B2570 04B2570 04
Rear Compartment Courtesy Lamp - Left Ground1
Rear Compartment Courtesy Lamp - Right Ground1
1. Rear Compartment Lamp Malfunction

The body control module (BCM) applies battery voltage to the rear compartment courtesy lamps through the rear compartment courtesy lamps control circuit. When the BCM receives a rear compartment lid open input from the rear compartment lid latch, the BCM applies battery voltage to the rear compartment courtesy lamps control circuit illuminating the rear compartment courtesy lamps. In the event that the rear compartment courtesy lamps were to remain illuminated for more than 10 min with the ignition switch in the OFF position, the BCM will deactivate the rear compartment courtesy lamps control circuit to prevent total battery discharge.

  1. Battery voltage must be between 9-16 V.
  2. Rear compartment OPEN.

DTC B2570 02

The BCM detects a short to ground in the rear compartment courtesy lamps control circuit.

DTC B2570 04

The BCM detects a short to voltage or an open/high resistance in the rear compartment courtesy lamps control circuit.

The rear compartment courtesy lamps are inoperative.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, exterior lamps OFF, disconnect the harness connectors at both E8 Rear Compartment Courtesy Lamps. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 5 ohms between the ground circuit terminal 2 and ground. If 5 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 1 and ground, ignition ON.
  4. Verify the test lamp turns ON and OFF when commanding the Trunk Lamp ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X7 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Ignition OFF, disconnect the X7 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  5. Test or replace the E8 Rear Compartment Courtesy Lamp.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for BCM replacement, programming, and setup

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
F6RA (BCM 4) Fuse B+B2575 01, B2575 04B2575 01, B2575 04
F43RA (BCM 3) Fuse B+B2699 01, B2699 04B2699 01, B2699 04
Low Beam Headlamp Control - Left (without T4F)B2575 02B2575 01, B2575 041
Low Beam Headlamp Control - Right (without T4F)B2699 02B2699 01, B2699 041
Headlamp Assembly - Left Ground1
Headlamp Assembly - Right Ground1
1. Headlamps Malfunction

With the headlamp switch in the ON position, the headlamp switch headlamp ON signal circuit is grounded through the headlamp switch. The body control module (BCM) responds by applying battery positive voltage to the left and right low beam headlamp control circuits illuminating the low beam headlamps.

  1. Battery voltage must be between 9-16 V.
  2. Low beam headlamps ON.

DTC B2575 01 and B2575 04

  1. The BCM detects an open/high resistance in the left low beam headlamp control circuit.
  2. The BCM detects a short to ground or an open/high resistance in the F43RA (BCM 3) fuse B+ circuit.

DTC B2575 02

The BCM detects a short to ground in the left low beam headlamp control circuit.

DTC B2699 01 and B2699 04

  1. The BCM detects an open/high resistance in the right low beam headlamp control circuit.
  2. The BCM detects a short to ground or an open/high resistance in the F6RA (BCM 4) fuse B+ circuit.

DTC B2699 02

The BCM detects a short to ground in the right low beam headlamp control circuit.

  1. When DTC B2575 sets, the left low beam headlamp will be inoperative.
  2. When DTC B2699 sets, the right low beam headlamp will be inoperative.
  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

DTC B2575

  1. Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module, ignition ON.
  2. Verify a test lamp illuminates between the B+ circuit terminal 3 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF, disconnect the X1 harness connector at the X53A Fuse Block - Rear Body. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF, disconnect the X1 harness connector at the X53A Fuse Block - Rear Body. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the X53A Fuse Block - Rear Body. If the test lamp illuminates
  3. Ignition OFF, connect the X1 harness connector at the K9 Body Control Module.
  4. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the E13LA Headlamp Assembly - Left. It may take up to 2 min for all vehicle systems to power down.
  5. Test for less than 15 ohms between the ground circuit terminal 3 and ground. If 15 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 15 ohms
  6. Connect a test lamp between the control circuit terminal 4 and ground, ignition ON.
  7. Verify the test lamp turns ON and OFF when commanding the Left Low Beam Headlamp ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  8. Test or replace the E4G Headlamp - Left Low Beam.

DTC B2699

  1. Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module, ignition ON.
  2. Verify a test lamp illuminates between the B+ circuit terminal 2 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF, disconnect the X3 harness connector at the X53A Fuse Block - Rear Body. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF, disconnect the X3 harness connector at the X53A Fuse Block - Rear Body. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the X53A Fuse Block - Rear Body. If the test lamp illuminates
  3. Ignition OFF, connect the X1 harness connector at the K9 Body Control Module.
  4. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the E13RA Headlamp Assembly - Right. It may take up to 2 min for all vehicle systems to power down.
  5. Test for less than 15 ohms between the ground circuit terminal 3 and ground. If 15 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 15 ohms
  6. Connect a test lamp between the control circuit terminal 4 and ground, ignition ON.
  7. Verify the test lamp turns ON and OFF when commanding the Right Low Beam Headlamp ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  8. Test or replace the E4H Headlamp - Right Low Beam.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Headlamp Bulb Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Rear Body Fuse Block Replacement»(/cadillac/ats/i-2012-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  3. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Turn Signal/Multifunction Switch Park Lamps ON Signal2B257A 002
Turn Signal/Multifunction Switch Headlamps OFF SignalB257A 0011
Turn Signal/Multifunction Switch Headlamps ON SignalB257A 0011
Turn Signal/Multifunction Switch Ground1, 2
1. Headlamps Malfunction 2. Park, License, and/or Tail Lamps Malfunction

For headlamp operation, the body control module (BCM) monitors three signal circuits from the turn signal/multifunction switch. When the turn signal/multifunction switch is in the AUTO position, the three signal circuits are unaffected and the BCM relies on the ambient light sensor input to turn the headlamps and daytime running lamps (DRLs) ON and OFF. When the turn signal/multifunction switch is placed in the OFF position, the turn signal/multifunction switch headlamps OFF signal circuit is grounded, indicating to the BCM that the exterior lamps should be turned OFF. With the turn signal/multifunction switch in the PARK LAMPS position, the turn signal/multifunction switch park lamps ON signal circuit is grounded, indicating that the park lamps have been requested. When the turn signal/multifunction switch is in the HEADLAMP position, both the turn signal/multifunction switch park lamps ON signal circuit and the turn signal/multifunction switch headlamps ON signal circuit are grounded. The BCM responds by commanding the park lamps and headlamps ON.

Battery voltage must be between 9-16 V.

  1. The BCM detects an open/high resistance in the turn signal/multifunction switch park lamps ON signal circuit.
  2. The BCM detects a short to ground in the turn signal/multifunction switch headlamps ON signal circuit.
  3. The BCM detects a short to ground in the turn signal/multifunction switch headlamps OFF signal circuit.
  1. When DTC B257A 00 is present on the turn signal/multifunction switch headlamps OFF signal circuit, the low beam headlamps are always ON in the AUTO position. The headlamp switch operates in all positions other than AUTO. The AUTO headlamp defeat is inoperative.
  2. When DTC B257A 00 is present on the turn signal/multifunction switch headlamps ON signal circuit, the low beam headlamps are always ON. The BCM disregards all turn signal/multifunction switch inputs.
  3. When DTC B257A 00 is present on the turn signal/multifunction switch park lamps ON signal circuit, the park lamps and low beam headlamps are inoperative in the PARK and HEAD positions. Headlamps and park lamps operate in AUTO position.
  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, scan tool disconnected, all doors closed, all accessories OFF, open and close drivers door, disconnect the harness connector at the S78 Turn Signal/Multifunction Switch. It may take up to 10 minutes for all vehicle systems to power down.
  2. Test for less than 5 ohms between the ground circuit terminal 6 and ground. If 5 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Ignition ON.
  4. Verify the scan tool Automatic Headlamps Disable Switch parameter is Inactive. If not Inactive Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 9 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  5. Install a 3 A fused jumper wire between the signal circuit terminal 9 and ground.
  6. Verify the scan tool Automatic Headlamps Disable Switch parameter is Active. If not Active Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the signal circuit terminal 9 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  7. Verify the scan tool Park Lamps Switch parameter is Inactive. If not Inactive Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 7 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  8. Install a 3 A fused jumper wire between the signal circuit terminal 7 and ground.
  9. Verify the scan tool Park Lamps Switch parameter is Active. If not Active Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the signal circuit terminal 7 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  10. Verify the scan tool Headlamps On Switch parameter is Inactive. If not Inactive Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 2 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  11. Install a 3 A fused jumper wire between the signal circuit terminal 2 and ground.
  12. Verify the scan tool Headlamps On Switch parameter is Active. If not Active Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the signal circuit terminal 2 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  13. Test or replace the S78 Turn Signal/Multifunction Switch.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Turn Signal Switch Replacement»(/cadillac/ats/i-2012-2014/remont/steering-column-switches/#steering-wheel-and-steering-column)
  2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The headlamp control module calculates the headlamp angle and sends commands to the left and right adaptive forward lighting system headlamp actuators. The headlamp actuators drive the headlamps to the position commanded by the headlamp control module. The headlamp control module monitors the headlamp actuator motor control circuits for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory and the driver will be notified with a "Service AFL Lamp" message displayed over the driver information center located on the instrument cluster.

  1. Battery voltage must be between 9-16 V.
  2. Engine RUNNING.
  3. Headlamps ON.

DTC B257C 00

The headlamp control module receives a serial data message from the left headlamp internal logic module that an internal headlamp malfunction has occurred.

DTC B257D 00

The headlamp control module receives a serial data message from the right headlamp internal logic module that an internal headlamp malfunction has occurred.

  1. The headlamp control module disables the AFL system.
  2. The driver information center will display AFL Lamps Need Service.
  3. On vehicles equipped with both AFL and headlamp leveling, the headlamp leveling system will remain active.
  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

DTC B257C and B257D will set when there is an internal malfunction within the left or right headlamp assemblies. No parts are serviceable within the headlamp assemblies so complete headlamp assembly replacement is necessary.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON.
  2. Verify DTC B257C or B257D is not set. If DTC B257C or B257D is set Program the K26 Headlamp Control Module. Verify the DTC does not set. If the DTC sets, replace the appropriate E13 Headlamp Assembly. If the DTC does not set All OK. If DTC B257C or B257D is not set
  3. All OK

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Headlamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Headlamp Control Module replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Headlamp High Beam Relay ControlB2580 02, B2580 04B2580 02, B2580 04B2580 01
High Beam Headlamp Control - Left111
High Beam Headlamp Control - Right111
Headlamp Ground - Left1
Headlamp Ground - Right1
1. Headlamps Malfunction

The high beam and flash to pass functions are contained within the turn signal/multifunction switch. The BCM provides the turn signal/multifunction switch with two signal circuits, the high beam signal circuit and the flash to pass signal circuit. When the low beam headlamps are ON and the turn signal/multifunction switch is placed in the high beam position, ground is applied to the BCM through the high beam signal circuit. The BCM responds to the high beam request by applying ground to the high beam relay control circuit which energizes the high beam relay. With the high beam relay energized, the switch contacts close allowing battery voltage to flow through the high beam fuses to the high beam control circuits illuminating the high beam headlamps.

  1. Battery voltage must be between 9-16 V.
  2. High beam headlamps ON.

DTC B2580 01

The BCM detects a short to voltage in the headlamp high beam relay control circuit.

DTC B2580 02

The BCM detects a short to ground in the headlamp high beam relay control circuit.

DTC B2580 04

The BCM detects an open in the headlamp high beam relay control circuit.

The high beam headlamps and flash to pass will not operate.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the X5 harness connector at the K9 Body Control Module, ignition ON.
  2. Verify a test lamp illuminates between the control circuit terminal 18 and ground. If the test lamp does not illuminate Ignition OFF, disconnect the X2 harness connector at the X50A Fuse Block - Underhood. Test for infinite resistance between the control circuit terminal and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the X50A Fuse Block - Underhood. If the test lamp illuminates
  3. Ignition OFF, connect a 3 A fused jumper between the control circuit terminal 18 and ground.
  4. Verify the high beam headlamps illuminate. If the high beam headlamps do not illuminate Ignition OFF, disconnect the X2 harness connector at the X50A Fuse Block - Underhood, ignition ON. Test for less than 1 V between the control circuit terminal 18 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the X50A Fuse Block - Underhood. If the high beam headlamps illuminate
  5. Test or replace the K9 Body Control Module.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Front Compartment Fuse Block Housing Replacement»(/cadillac/ats/i-2012-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Headlamp Switch Park Lamps ON Signal2B257A 002
Park Lamps Control - Terminal 11 X4B2585 02B2585 04B2585 01, B2585 04
Headlamp Switch Ground2
Tail Lamp Ground - Left1
Side Marker Lamp Ground - Left Front1
Side Marker Lamp Ground - Right Front1
1. Park, License, and/or Tail Lamps Malfunction 2. Park Lamp Switch Malfunction

When the headlamp switch is placed in the HEAD or PARK position, ground is applied to the park lamp switch ON signal circuit to the body control module (BCM). The BCM responds by applying voltage to the park lamps, tail lamps, and license lamps control circuits illuminating the park, tail, and license lamps.

  1. Battery voltage must be between 9-16 V.
  2. Park lamps ON.

DTC B2585 01 and B2585 04

The BCM detects a short to voltage or an open/high resistance in the park lamps control circuit terminal 11 X4.

DTC B2585 02

The BCM detects a short to ground in the park lamps control circuit terminal 11 X4.

DTC B2585 01

The park lamps are always ON.

DTC B2585 02 and B2585 04

The park lamps are always OFF.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, exterior lamps OFF, trunk latch latched, disconnect the harness connector at the appropriate front side marker lamp or left rear tail lamp.
  2. Test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground. E2LF side marker lamp - left front terminal 1 E2RF side marker lamp - left front terminal 1 E5E tail lamp - left terminal 5 If 5 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the appropriate control circuit terminal listed below and ground, ignition ON. E2LF side marker lamp - left front terminal 2 E2RF side marker lamp - left front terminal 2 E5E tail lamp - left terminal 1
  4. Verify the test lamp turns ON and OFF when commanding the Left Park Lamps ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X4 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Ignition OFF, disconnect the X4 harness connector at the K9 body control module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the appropriate park lamp.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Tail Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Front Side Marker Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  3. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Headlamp Low Beam Relay ControlB258A 02, B258A 04B258A 02, B258A 04, U1511 00, U1521 00B258A 01, U1511 00, U1521 00
Low Beam Headlamp Control - Left111
Low Beam Headlamp Control - Right111
Headlamp Ground - Left1
Headlamp Ground - Right1
1. Headlamps Malfunction

With the headlamp switch in the ON position, the headlamp switch headlamp ON signal circuit is grounded through the headlamp switch. The body control module (BCM) responds by applying ground to the low beam relay control circuit which energizes the low beam relay. With the low beam relay energized, the switch contacts close allowing battery voltage to flow through the low beam fuses to the low beam control circuits illuminating the low beam headlamps.

  1. Battery voltage must be between 9-16 V.
  2. Low beam headlamps ON.

DTC B258A 01

The BCM detects a short to voltage in the headlamp low beam relay control circuit.

DTC B258A 02 and B258A 04

The BCM detects a short to ground or an open/high resistance in the headlamp low beam relay control circuit.

DTC B258A 01 or B258A 04

  1. The low beam headlamps will not operate.
  2. The driver information center will display "Left Low Beam Failure" and "Right Low Beam Failure".

DTC B258A 02

The low beam headlamps will always be ON.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the KR49 Headlamp Low Beam Relay.
  2. Connect a test lamp between the control circuit terminal 85 and B+, ignition ON.
  3. Verify the test lamp turns ON and OFF when commanding the Low Beam Lamps ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X5 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Ignition OFF. Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Ignition OFF, disconnect the X5 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit terminal and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  4. Test or replace the KR49 Headlamp Low Beam Relay.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Relay Replacement (Within an Electrical Center)»(/cadillac/ats/i-2012-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions__relay-replacement-within-an-electrical-center) , «Relay Replacement (Attached to Wire Harness)»(/cadillac/ats/i-2012-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
BCM 3 Fuse B+11
BCM 4 Fuse B+11
Ambient Light Sensor SignalB2645 03B2645 07B2645 07
Daytime Running Lamp Control - LeftB260D 0211
Daytime Running Lamp Control - RightB260E 0211
Ambient Light Sensor Low Reference1B2645 07, B0163 05, B0183 051
Daytime Running Lamp Ground - Left1
Daytime Running Lamp Ground - Right1
1. Daytime Running Lamps Malfunction

The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 volts depending on outside lighting conditions. The body control module (BCM) provides a 5-volt reference signal to the ambient light sensor and the HVAC control module provides a low reference ground. The BCM monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control (ALC) when the headlamp switch is in the AUTO position. In daylight conditions the BCM will command the DRLs ON. During low light conditions the BCM will command the low beam headlamps ON. Any function or condition that turns on the headlamps will cancel DRL operation.

Battery voltage must be between 9-16 V.

DTC B260D 02

The BCM detects a short to ground in the left daytime running lamp control circuit.

DTC B260E 02

The BCM detects a short to ground in the right daytime running lamp control circuit.

DTC B260D 02

The left daytime running lamp is inoperative.

DTC B260E 02

The right daytime running lamp is inoperative.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

  1. «Headlights/Daytime Running Lights (DRL) Schematics»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-schematic-wiring-diagrams)
  2. «Body Control System Schematics»(/cadillac/ats/i-2012-2014/remont/communication-devices/#data-communication-system)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate E13 headlamp. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 5 ohms between the ground circuit terminal 2 and ground. If 5 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal 4 and ground, ignition ON.
  4. Verify the test lamp turns ON and OFF when commanding the appropriate Dedicated Daytime Running Lamp ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the appropriate harness connector listed below at the K9 body control module. X4 - left daytime running lamp X5 - right daytime running lamp Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Ignition OFF, disconnect the appropriate harness connector listed below at the K9 body control module, ignition ON. X4 - left daytime running lamp X5 - right daytime running lamp Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the appropriate E4 daytime running lamp.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Daytime Running Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Instrument Panel Dimmer Switch B+B1395 03, B3600 03B1395 03, B3600 03B1395 07, B3600 07
Instrument Panel Dimmer Switch SignalB1395 03, B3600 03B1395 03, B3600 03B1395 07, B3600 07
LED Backlight Dimming Control Terminal 8 X2B2610 02B2610 041
LED Backlight Dimming Control Terminal 9 X7B2610 02B2610 041
Instrument Panel Dimmer Switch Low Reference111
Dome Lamp Switch Ground1
Door Lock Switch - Driver1
Door Lock Switch - Passenger1
Dome/Reading Lamp - Left Roof Rail Ground1
Dome/Reading Lamp - Right Roof Rail Ground1
Dome/Reading Lamps - Rear Ground1
Garage Door Opener Switch Ground1
Headlamp Switch Ground1
Instrument Panel Dimmer Switch Ground1
Multifunction Switch 1 - Instrument Panel Ground1
Multifunction Switch 2 - Instrument Panel Ground1
Outside Rearview Mirror Switch Ground1
Park Brake Control Switch Ground1
Seat Heating Switch - Left Rear Ground1
Seat Heating Switch - Right Rear Ground1
Steering Wheel Controls Switch - Left Ground1
Steering Wheel Controls Switch - Right Ground1
Sunroof Switch Ground1
1. Interior Backlighting Malfunction

The instrument panel dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The instrument panel dimmer switch provides a voltage signal to the body control module (BCM) that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The BCM provides a low reference, signal, and B+ voltage reference circuits to the instrument panel dimmer switch. When the instrument panel dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the instrument panel dimmer switch through the instrument panel dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies a pulse width modulated (PWM) voltage through the LED dimming control circuits illuminating the interior backlighting to the requested level of brightness.

  1. Battery voltage must be between 9-16 V.
  2. Park lamps ON.

DTC B2610 02

The BCM detects a short to ground in the LED backlight dimming control 1 circuit terminal 8 X2 or LED backlight dimming control 2 circuit terminal 9 X7.

DTC B2610 04

The BCM detects an open/high resistance in the LED backlight dimming control 1 circuit terminal 8 X2 or LED backlight dimming control 2 circuit terminal 9 X7.

The BCM will disable the LED backlight dimming control circuits.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, all doors closed, all accessories OFF, disconnect the harness connector at the component with inoperative backlighting. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 15 ohms between the appropriate ground circuit terminal and ground. If 15 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 15 ohms
  3. Connect a test lamp between the appropriate control circuit terminal and ground.
  4. Verify the test lamp turns ON and OFF when commanding the LED Backlight Dimming ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the appropriate harness connector listed below at the K9 Body Control Module. X2 terminal 8 X7 terminal 9 Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Ignition OFF, disconnect the appropriate harness connector listed below at the K9 Body Control Module, ignition ON. X2 terminal 8 X7 terminal 9 Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  5. Test or replace the component with inoperative backlighting.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Interior Lamp Switch Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Dome and Reading Lamp Switch Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  3. «Roof Rail Rear Seat Position Reading and Courtesy Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  4. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Dome/Courtesy Lamps Control 1 - Terminal 1 X7B2615 02B2615 042
Dome/Courtesy Lamps Control 2 - Terminal 5 X2B2615 02B2615 042
Door Courtesy Lamp - Driver Ground1
Door Courtesy Lamp - Passenger Ground1
Door Courtesy Lamp - Left Rear Ground1
Door Courtesy Lamp - Right Rear Ground1
Door Sill Plate Lamp - Driver Ground1
Door Sill Plate Lamp - Passenger Ground1
Dome/Reading Lamps - Left Front Ground1
Dome/Reading Lamps - Left Rear Ground1
Dome/Reading Lamps - Right Front Ground1
Dome/Reading Lamps - Right Rear Ground1
Instrument Panel Courtesy Lamp - Left Ground1
Instrument Panel Courtesy Lamp - Right Ground1
Seat Courtesy Lamp - Left Rear Ground1
Seat Courtesy Lamp - Right Rear Ground1
1. Dome Lamps Malfunction 2. Courtesy Lamps Malfunction

The body control module (BCM) applies battery voltage to the dome/reading lamps through the dome/reading lamp control circuit. When any door is opened, the jam switch contacts close and the BCM receives a door-ajar input. If the BCM receives a door lock or unlock input or a rear hatch open input, the BCM will activate the dome/reading lamp control circuit, providing battery voltage to dome/reading lamps. In the event that any of these courtesy lamps were to remain illuminated for more than 10 minutes with the ignition switch in the OFF position and no doors opened, the BCM will deactivate the courtesy lamp control circuit to prevent total battery discharge.

Battery voltage must be between 9-16 V.

The BCM detects a short to ground in the dome/courtesy lamps control circuit terminal 1 X7 and terminal 5 X2.

The BCM will disable the dome/courtesy lamps control circuit.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, all doors closed, all accessories OFF, disconnect the harness connector at the inoperative component. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 ohms between the appropriate ground circuit terminal and ground. If 10 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 10 ohms
  3. Connect a test lamp between the appropriate control circuit terminal and ground.
  4. Verify the test lamp turns ON and OFF when commanding the Courtesy Lamps ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X2 and X7 harness connectors at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Ignition OFF, disconnect the X2 and X7 harness connectors at the K9 body control module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the appropriate dome/reading/courtesy lamp.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Roof Rail Rear Seat Position Reading and Courtesy Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Front Side Door Courtesy Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  3. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Switch Indicator LED Backlight Dimming Control Terminal 5 X1B2625 02B2625 04B2625 01
Door Lock Switch - Driver Ground1
Door Lock Switch - Passenger Ground1
1. Interior Backlighting Malfunction

The instrument panel dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The instrument panel dimmer switch provides a voltage signal to the body control module (BCM) that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The BCM provides a low reference, signal, and B+ voltage reference circuits to the instrument panel dimmer switch. When the instrument panel dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the instrument panel dimmer switch through the instrument panel dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies a pulse width modulated (PWM) voltage through the LED backlight dimming control circuit illuminating the LED backlighting to the requested level of brightness.

  1. Battery voltage must be between 9-16 V.
  2. Park lamps ON.

The BCM detects a short to ground in the LED backlight dimming control circuit terminal 5 X1.

The LED backlight dimming control circuit driver is shut down.

  1. The condition responsible for setting the DTC no longer exists.
  2. Disconnect the negative battery cable for 30 seconds.
  3. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connectors at the components listed below. S13D Door Lock Switch - Driver S13P Door Lock Switch - Passenger
  2. Connect a test lamp between the appropriate control circuit terminal listed below and ground. S13D Door Lock Switch - Driver terminal 5 S13P Door Lock Switch - Passenger terminal 5
  3. Verify the test lamp turns ON and OFF when commanding the LED Backlight Dimming ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  4. Test or replace the appropriate S13 Door Lock Switch.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Door Lock Switch Replacement - Driver Side»(/cadillac/ats/i-2012-2014/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems)
  2. «Door Lock Switch Replacement - Passenger Front»(/cadillac/ats/i-2012-2014/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems)
  3. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Exterior Courtesy Lamps Control Terminal 8 X7B263A 02B263A 041
Accent Lamp - Driver Door Handle1
Accent Lamp - Passenger Door Handle1
Accent Lamp - Left Rear Door Handle1
Accent Lamp - Right Rear Door Handle1
Outside Rearview Mirror - Driver Ground1
Outside Rearview Mirror - Passenger Ground1
1. Exterior Courtesy Lamps Malfunction

The body control module (BCM) supplies battery voltage to the exterior door handles LED backlighting and the LED lighting located under each outside rearview mirror for approach lighting. When the keyless entry transmitter is operated to the lock/unlock functions the exterior door handles LED and the LED lighting located under each outside rearview mirror for approach lighting are commanded ON.

  1. Battery voltage must be between 9-16 V.
  2. Park lamps ON.

DTC B263A 02

The BCM detects a short to ground in the exterior courtesy lamps control circuit terminal 8 X7.

DTC B263A 04

The BCM detects an open/high resistance in the exterior courtesy lamps control circuit terminal 8 X7.

The BCM will disable the exterior courtesy lamps control circuit.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, all doors closed, all accessories OFF, disconnect the harness connector at the inoperative component. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 15 ohms between the appropriate ground circuit terminal listed below and ground. A9A outside rearview mirror - driver terminal 5 A9B outside rearview mirror - passenger terminal 5 B27D door handle switch - driver exterior terminal 4 B27P door handle switch - passenger exterior terminal 4 B27LR door handle switch - left rear exterior terminal 4 B27RR door handle switch - right rear exterior terminal 4 If 15 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 15 ohms
  3. Connect a test lamp between the appropriate control circuit terminal listed below and ground. A9A outside rearview mirror - driver terminal 17 A9B outside rearview mirror - passenger terminal 17 B27D door handle switch - driver exterior terminal 5 B27P door handle switch - passenger exterior terminal 5 B27LR door handle switch - left rear exterior terminal 5 B27RR door handle switch - right rear exterior terminal 5
  4. Verify the test lamp turns ON and OFF when commanding the Exterior Courtesy Lamps ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X7 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Ignition OFF, disconnect the X7 harness connector at the K9 body control module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the component with inoperative component.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Front Side Door Outside Handle Replacement»(/cadillac/ats/i-2012-2014/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems)
  2. «Rear Side Door Outside Handle Replacement»(/cadillac/ats/i-2012-2014/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems)
  3. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
BCM 3 Fuse B+11
BCM 4 Fuse B+11
Ambient Light Sensor SignalB2645 03B2645 07B2645 07
Daytime Running Lamp Control - LeftB260D 0211
Daytime Running Lamp Control - RightB260E 0211
Ambient Light Sensor Low Reference1B2645 07, B0163 05, B0183 051
Daytime Running Lamp Ground - Left1
Daytime Running Lamp Ground - Right1
1. Daytime Running Lamps Malfunction

The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 volts depending on outside lighting conditions. The body control module (BCM) provides a 5-volt reference signal to the ambient light sensor and the HVAC control module provides a low reference ground. The BCM monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control (ALC) when the headlamp switch is in the AUTO position. In daylight conditions the BCM will command the DRLs ON. During low light conditions the BCM will command the low beam headlamps ON. Any function or condition that turns on the headlamps will cancel DRL operation.

Battery voltage must be between 9-16 V.

DTC B2645 03

The BCM detects a short to ground in the ambient light sensor signal circuit.

DTC B2645 07

  1. The BCM detects a short to voltage or an open/high resistance in the ambient light sensor signal circuit.
  2. The BCM detects an open/high resistance in the ambient light sensor low reference circuit.
  1. Automatic headlamp system and daytime running lamps are inoperative.
  2. The BCM defaults to low light status and commands the low beam headlamps ON.
  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the B10B ambient light/sunload sensor. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 ohms between the low reference circuit terminal 6 and ground. If 10 ohms or greater Ignition OFF, disconnect the X2 harness connector at the K33 HVAC control module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC control module. If less than 10 ohms
  3. Ignition ON.
  4. Verify the scan tool Ambient Light Sensor parameter is greater than 4.65 V. If 4.65 V or less Ignition OFF, disconnect the X2 harness connector at the K9 body control module. Test for infinite resistance between the signal circuit terminal 5 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 body control module. If greater than 4.65 V
  5. Install a 3 A fused jumper wire between the signal circuit terminal 5 and the low reference circuit terminal 6.
  6. Verify the scan tool Ambient Light Sensor parameter is less than 0.196 V. If 0.196 V or greater Ignition OFF, disconnect the X2 harness connector at the K9 body control module, ignition ON. Test for less than 1 V between the signal circuit terminal 5 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If less than 0.196 V
  7. Test or replace the B10B ambient light/sunload sensor.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Sun Load Temperature Sensor Replacement»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic)
  2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or HVAC Control Module replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
LIN Serial Data - Left Headlamp Leveling ActuatorU1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05
LIN Serial Data - Right Headlamp Leveling ActuatorU1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05
Headlamp Control Module B+ Fuse (F29 UA)U0181 00U0181 00
Headlamp Leveling Actuator - Left B+ Fuse (F63 UA)U1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05
Headlamp Leveling Actuator - Right B+ Fuse (F63 UA)U1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05
Suspension Position Sensor 5V Reference - Left FrontB3415 021B3415 01
Suspension Position Sensor 5V Reference - Left RearB3415 021B3415 01
Suspension Position Sensor Signal - Left FrontB3410 06B3410 06B3410 01B3410 08
Suspension Position Sensor Signal - Left RearB3420 06B3420 06B3420 01B3420 08
Suspension Position Sensor Low Reference - Left Front1
Suspension Position Sensor Low Reference - Left Rear1
Headlamp Control Module Ground1
Headlamp Assembly - Left Ground1
Headlamp Assembly - Right Ground1
1. Headlamp Leveling Malfunction

Each headlamp assembly contains a headlamp leveling motor that is controlled by the headlamp control module. The front and rear suspension position sensors provide the headlamp control module with suspension position information. Each sensor receives a 5-volt reference, signal, and low reference circuits from the headlamp control module. The sensors are connected to the control arms of the front and rear suspension. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensor arms. This causes the signal output of the sensor to change. The headlamp control module compares the information from both suspension position sensors and adjusts the headlamp leveling as needed.

  1. Battery voltage must be between 9-16 V.
  2. Engine RUNNING.
  3. Headlamps ON.

DTC B3410 01

The headlamp control module detects a short to voltage in the front suspension position sensor signal circuit.

DTC B3410 06

The headlamp control module detects a short to ground or an open/high resistance in the front suspension position sensor signal circuit.

DTC B3420 01

The headlamp control module detects a short to voltage in the rear suspension position sensor signal circuit.

DTC B3420 06

The headlamp control module detects a short to ground or an open/high resistance in the rear suspension position sensor signal circuit.

  1. The headlamp control module disables the headlamp leveling system.
  2. The driver information center will display "Adaptive Forward Lighting" and "Headlamp Leveling Malfunction".
  3. On vehicles equipped with both AFL and headlamp leveling, the AFL system will remain active.
  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the appropriate B152L Suspension Position Sensor, ignition ON.
  2. Verify a test lamp illuminates between the low reference circuit terminal 2 and B+. If the test lamp does not illuminate Ignition OFF, disconnect the harness connector at the K26 Headlamp Control Module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K26 Headlamp Control Module. If the test lamp illuminates
  3. Ignition ON.
  4. Test for 4.8-5.2 V between the 5 V reference circuit terminal 1 and ground. If less than 4.8 V Ignition OFF, disconnect the harness connector at the K26 Headlamp Control Module. Test for infinite resistance between the 5 V reference circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the 5 V reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K26 Headlamp Control Module. If greater than 5.2 V Ignition OFF, disconnect the harness connector at the K26 Headlamp Control Module, ignition ON. Test for less than 1 V between the 5 V reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K26 Headlamp Control Module. If between 4.8-5.2 V
  5. Verify the appropriate scan tool Suspension Position Sensor parameter is less than 1 V. If 1 V or greater Ignition OFF, disconnect the harness connector at the K26 Headlamp Control Module, ignition ON. Test for less than 1 V between the signal circuit terminal 3 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K26 Headlamp Control Module. If less than 1 V
  6. Install a 3 A fused jumper wire between the 5-volt reference circuit terminal 1 and the signal circuit terminal 3.
  7. Engine RUNNING, verify the appropriate scan tool Suspension Position Sensor parameter is greater than 4.8 V. If less than 4.8 V Ignition OFF, disconnect the harness connector at the K26 Headlamp Control Module. Test for infinite resistance between the signal circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K26 Headlamp Control Module. If 4.8 V or greater
  8. Test or replace the appropriate B152L Suspension Position Sensor.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Electronic Suspension Front Position Sensor Replacement»(/cadillac/ats/i-2012-2014/remont/electronic-suspension/#suspension-control-system-suspension-damping)
  2. «Electronic Suspension Rear Position Sensor Replacement»(/cadillac/ats/i-2012-2014/remont/electronic-suspension/#suspension-control-system-suspension-damping)
  3. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Headlamp Control Module replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
LIN Serial Data - Left Headlamp Leveling ActuatorU1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05
LIN Serial Data - Right Headlamp Leveling ActuatorU1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05
Headlamp Control Module B+ Fuse (F29 UA)U0181 00U0181 00
Headlamp Leveling Actuator - Left B+ Fuse (F63 UA)U1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05
Headlamp Leveling Actuator - Right B+ Fuse (F63 UA)U1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05
Suspension Position Sensor 5V Reference - Left FrontB3415 021B3415 01
Suspension Position Sensor 5V Reference - Left RearB3415 021B3415 01
Suspension Position Sensor Signal - Left FrontB3410 06B3410 06B3410 01B3410 08
Suspension Position Sensor Signal - Left RearB3420 06B3420 06B3420 01B3420 08
Suspension Position Sensor Low Reference - Left Front1
Suspension Position Sensor Low Reference - Left Rear1
Headlamp Control Module Ground1
Headlamp Assembly - Left Ground1
Headlamp Assembly - Right Ground1
1. Headlamp Leveling Malfunction

Each headlamp assembly contains a headlamp leveling motor that is controlled by the headlamp control module. The front and rear suspension position sensors provide the headlamp control module with suspension position information. Each sensor receives a 5-volt reference, signal, and low reference circuits from the headlamp control module. The sensors are connected to the control arms of the front and rear suspension. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensor arms. This causes the signal output of the sensor to change. The headlamp control module compares the information from both suspension position sensors and adjusts the headlamp leveling as needed.

  1. Battery voltage must be between 9-16 V.
  2. Engine RUNNING.
  3. Headlamps ON.

DTC B3415 01

The headlamp control module detects a short to voltage in the suspension position sensor 5V reference circuit.

DTC B3415 02

The headlamp control module detects a short to ground or an open/high resistance in the suspension position sensor 5V reference circuit.

  1. The headlamp control module disables the headlamp leveling system.
  2. The driver information center will display "Adaptive Forward Lighting" and "Headlamp Leveling Malfunction".
  3. On vehicles equipped with both AFL and headlamp leveling, the AFL system will remain active.
  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the appropriate B152L Suspension Position Sensor, ignition ON.
  2. Verify a test lamp illuminates between the low reference circuit terminal 2 and B+. If the test lamp does not illuminate Ignition OFF, disconnect the harness connector at the K26 Headlamp Control Module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K26 Headlamp Control Module. If the test lamp illuminates
  3. Ignition ON.
  4. Test for 4.8-5.2 V between the 5 V reference circuit terminal 1 and ground. If less than 4.8 V Ignition OFF, disconnect the harness connector at the K26 Headlamp Control Module. Test for infinite resistance between the 5 V reference circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the 5 V reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K26 Headlamp Control Module. If greater than 5.2 V Ignition OFF, disconnect the harness connector at the K26 Headlamp Control Module, ignition ON. Test for less than 1 V between the 5 V reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K26 Headlamp Control Module. If between 4.8-5.2 V
  5. Verify the appropriate scan tool Suspension Position Sensor parameter is less than 1 V. If 1 V or greater Ignition OFF, disconnect the harness connector at the K26 Headlamp Control Module, ignition ON. Test for less than 1 V between the signal circuit terminal 3 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K26 Headlamp Control Module. If less than 1 V
  6. Install a 3 A fused jumper wire between the 5-volt reference circuit terminal 1 and the signal circuit terminal 3.
  7. Engine RUNNING, verify the appropriate scan tool Suspension Position Sensor parameter is greater than 4.8 V. If less than 4.8 V Ignition OFF, disconnect the harness connector at the K26 Headlamp Control Module. Test for infinite resistance between the signal circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K26 Headlamp Control Module. If 4.8 V or greater
  8. Test or replace the appropriate B152L Suspension Position Sensor.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Electronic Suspension Front Position Sensor Replacement»(/cadillac/ats/i-2012-2014/remont/electronic-suspension/#suspension-control-system-suspension-damping)
  2. «Electronic Suspension Rear Position Sensor Replacement»(/cadillac/ats/i-2012-2014/remont/electronic-suspension/#suspension-control-system-suspension-damping)
  3. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Headlamp Control Module replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
LIN Serial Data - Left Headlamp Leveling ActuatorU1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05
LIN Serial Data - Right Headlamp Leveling ActuatorU1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05
Headlamp Control Module B+ Fuse (F29 UA)U0181 00U0181 00
Headlamp Leveling Actuator - Left B+ Fuse (F63 UA)U1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05
Headlamp Leveling Actuator - Right B+ Fuse (F63 UA)U1513 00, U1514 00, U1523 00, U1524 00, B3843 05U1513 00, U1514 00, U1523 00, U1524 00, B3843 05
Suspension Position Sensor 5V Reference - Left FrontB3415 021B3415 01
Suspension Position Sensor 5V Reference - Left RearB3415 021B3415 01
Suspension Position Sensor Signal - Left FrontB3410 06B3410 06B3410 01B3410 08
Suspension Position Sensor Signal - Left RearB3420 06B3420 06B3420 01B3420 08
Suspension Position Sensor Low Reference - Left Front1
Suspension Position Sensor Low Reference - Left Rear1
Headlamp Control Module Ground1
Headlamp Leveling Actuator - Left Ground1
Headlamp Leveling Actuator - Right Ground1
1. Headlamp Leveling Malfunction

Each headlamp assembly contains a headlamp leveling actuator that is controlled by the headlamp control module. The front and rear suspension position sensors provide the headlamp control with suspension position information. Each sensor receives a 5 V reference, signal, and low reference circuits from the headlamp control module. The sensors are connected to the control arms of the front and rear suspension. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensor arms. This causes the signal output of the sensor to change. The headlamp control module compares the information from both suspension position sensors and adjusts the headlamp leveling as needed. The headlamp control module communicates with the left and right headlamp leveling actuators via the LIN serial data circuit.

  1. Battery voltage must be between 9-16 V.
  2. Ignition ON.
  3. Headlamps ON.

DTC B3435 00

  1. The headlamp control module detects a short to ground or an open/high resistance in the left headlamp leveling actuator LIN bus circuit.
  2. The headlamp control module detects an open/high resistance in the left headlamp leveling actuator ground circuit.

DTC B3435 03

  1. The headlamp control module detects a short to ground or an open/high resistance in the left headlamp leveling actuator B+ circuit.
  2. The headlamp control module detects an open/high resistance in the left headlamp leveling actuator ground circuit.

DTC B3440 00

  1. The headlamp control module detects a short to ground or an open/high resistance in the right headlamp leveling actuator LIN bus circuit.
  2. The headlamp control module detects an open/high resistance in the right headlamp leveling actuator ground circuit.

DTC B3440 03

  1. The headlamp control module detects a short to ground or an open/high resistance in the right headlamp leveling actuator B+ circuit.
  2. The headlamp control module detects an open/high resistance in the right headlamp leveling actuator ground circuit.
  1. The headlamp control module disables the headlamp leveling system.
  2. The driver information center will display "Adaptive Forward Lighting" and "Headlamp Leveling Malfunction".
  3. On vehicles equipped with both AFL and headlamp leveling, the AFL system will remain active.
  1. The condition responsible for setting the DTC no longer exists and the ignition is cycled.
  2. A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate E13 Headlamp Assembly.
  2. Test for less than 15 ohms between the ground circuit terminal 7 and ground. If 15 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 15 ohms
  3. Ignition ON.
  4. Verify a test lamp illuminates between the B+ circuit terminal 8 and ground. If the test lamp does not illuminate Ignition OFF, disconnect the X1 harness connector at the X50A Fuse Block - Underhood. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the X50A Fuse Block - Underhood. If the test lamp illuminates
  5. Test or replace the K26 Headlamp Control Module.
  6. Ignition ON.
  7. Verify the appropriate headlamp operates to the UP and DOWN positions when commanding the appropriate Headlamp Vertical Motor UP and DOWN with a scan tool. If the headlamp does not operate UP and DOWN Test or replace the E13 Headlamp Assembly. If the headlamp operates UP and DOWN
  8. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Headlamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Front Compartment Fuse Block Housing Replacement»(/cadillac/ats/i-2012-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  3. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Headlamp Control Module replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Rear Fog Lamp Switch SignalB3588 0011
Rear Fog Lamp ControlB2540 02B2540 041
Rear Fog Lamp Ground1
Turn Signal/Multifunction Switch Ground1
1. Rear Fog Lamp Malfunction

The rear fog lamp switch signal circuit is grounded momentarily by pressing the rear fog lamp switch. The body control module (BCM) responds to the rear fog lamp request by applying voltage to the rear fog lamp control circuit which illuminates the rear fog lamp.

Battery voltage must be between 9-16 V.

The BCM detects a short to ground in the turn signal/multifunction switch rear fog lamp signal circuit.

The rear fog lamp indicator on the instrument cluster is always ON.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, scan tool disconnected, all doors closed, all accessories OFF, open and close drivers door, disconnect the harness connector at the S78 Turn Signal/Multifunction Switch. It may take up to 10 minutes for all vehicle systems to power down.
  2. Test for less than 5 ohms between the ground circuit terminal 6 and ground. If 5 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Ignition ON.
  4. Verify the scan tool Rear Fog Lamp Switch parameter is Inactive. If not Inactive Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 3 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  5. Install a 3 A fused jumper wire between the signal circuit terminal 3 and ground.
  6. Verify the scan tool Rear Fog Lamp Switch parameter is Active. If not Active Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the signal circuit terminal 3 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  7. Test or replace the S78 Turn Signal/Multifunction Switch.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Turn Signal Switch Replacement»(/cadillac/ats/i-2012-2014/remont/steering-column-switches/#steering-wheel-and-steering-column)
  2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Hazard Warning Switch Signal111B3596 00
Hazard Warning Switch LED Backlighting Control222
Hazard Warning Switch Ground1, 2
1. Hazard Lamps Malfunction 2. Hazard Warning Switch Backlighting Malfunction

The hazard flashers may be activated in any power mode. The hazard warning switch signal circuit is momentarily grounded when the hazard warning switch is pressed. The body control module (BCM) responds to the hazard warning switch signal input by supplying battery voltage to all four turn signal lamps in an ON and OFF duty cycle. When the hazard warning switch is activated, the BCM sends a serial data message to the instrument cluster requesting both turn signal indicators to be cycled ON and OFF.

  1. Battery voltage must be between 9-16 V.
  2. Hazard lamps ON.

The hazard warning switch input is Active for longer than 60 seconds.

The hazard lamps are inoperative.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the appropriate component listed below. It may take up to 2 minutes for all vehicle systems to power down. S26 Hazard Warning Switch S48C Multifunction Switch 1 - Instrument Panel
  2. Test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground. S26 Hazard Warning Switch - terminal 4 S48C Multifunction Switch 1 - Instrument Panel terminal 5 If 5 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Ignition ON.
  4. Verify the scan tool Hazard Lamps Switch parameter is Inactive. If not Inactive Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module. Test for infinite resistance between the appropriate signal circuit terminal listed below and ground. S26 Hazard Warning Switch - terminal 6 S48C Multifunction Switch 1 - Instrument Panel terminal 7 If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  5. Install a 3 A fused jumper wire between the appropriate signal and ground circuit terminals listed below. S26 Hazard Warning Switch - signal terminal 6 and ground terminal 4 S48C Multifunction Switch 1 - Instrument Panel signal terminal 7 and ground terminal 5
  6. Verify the scan tool Hazard Lamps Switch parameter is Active. If not Active Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the signal circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  7. Test or replace the S26 Hazard Warning Switch.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Hazard Warning Switch Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Instrument Panel Dimmer Switch B+ ReferenceB1395 03, B3600 03B1395 03, B3600 03B1395 07, B3600 07
Instrument Panel Dimmer Switch SignalB1395 03, B3600 03B1395 03, B3600 03B1395 07, B3600 07
Instrument Panel Dimmer Switch Low Reference111
1. Interior Backlighting Malfunction

The instrument panel dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The instrument panel dimmer switch provides a voltage signal to the body control module (BCM) that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The BCM provides a low reference, signal, and B+ voltage reference to the instrument panel dimmer switch. When the instrument panel dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the instrument panel dimmer switch through the instrument panel dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies a pulse width modulated (PWM) voltage through the LED dimming 1 and dimming 2 control circuits illuminating the interior backlighting to the requested level of brightness.

  1. Battery voltage must be between 9-16 V.
  2. Park Lamps ON.

DTC B3600 03

  1. The BCM detects a short to ground or an open/high resistance in the instrument panel dimmer switch B+ reference circuit.
  2. The BCM detects a short to ground or an open/high resistance in the instrument panel dimmer switch signal circuit.

DTC B3600 07

  1. The BCM detects a short to voltage in the instrument panel dimmer switch B+ reference circuit.
  2. The BCM detects a short to voltage in the instrument panel dimmer switch signal circuit.

The BCM will not dim any interior backlighting. All interior backlighting will default to the FULL bright.

  1. The condition responsible for setting the DTC no longer exists.
  2. Disconnect the negative battery cable for 30 seconds.
  3. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

When a short to ground condition exists, the BCM goes into safe mode. The DTC will clear in most cases without removing the negative battery cable, but in order to restore the BCM to normal operating conditions the negative battery cable must be removed. The B+ reference circuit under normal operating conditions will illuminate a test lamp. When the BCM is in safe mode, a test lamp will no longer illuminate but the DTC will clear and the backlighting will dim normally.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S36 Instrument Panel Dimmer Switch, ignition ON.
  2. Test for B+ between the B+ circuit terminal 6 and ground. If less than B+ Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If B+
  3. Verify a test lamp illuminates between the B+ circuit terminal 6 and the low reference circuit terminal 1. If the test lamp does not illuminate Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the low reference circuit terminal 1 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp illuminates
  4. Verify a test lamp does not illuminate between the B+ circuit terminal 6 and the signal circuit terminal 2. If the test lamp illuminates Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If the test lamp does not illuminate
  5. Test for B+ between the B+ circuit terminal 6 and the signal circuit terminal 2. If less than B+ Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the signal circuit terminal 2 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If B+
  6. Test or replace the S36 Instrument Panel Dimmer Switch.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Interior Lamp and Multifunction Switch Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Turn Signal/Multifunction Switch Headlamps OFF SignalB257A 0011
Turn Signal/Multifunction Switch Headlamps ON SignalB257A 0011
Turn Signal/Multifunction Switch Park Lamps ON Signal2B257A 002
Turn Signal/Multifunction Switch Flash To Pass SignalB3806 0011
Turn Signal/Multifunction Switch High Beam SignalB3650 0811
Turn Signal/Multifunction Switch Ground1
1. Headlamps Malfunction 2. Park, License, and/or Tail Lamps Malfunction

When the low beam headlamps are on and the turn signal/multifunction switch is placed in the high beam position, ground is applied to the body control module (BCM) through the high beam signal circuit. The BCM responds to the high beam request by applying ground to the high beam relay control circuit which energizes the high beam relay. With the high beam relay energized, the switch contacts close allowing battery voltage to flow through the high beam fuses to the high beam control circuits illuminating the high beam headlamps.

Battery voltage must be between 9-16 V.

The BCM detects a short to ground in the turn signal/multifunction switch high beam signal circuit.

The high beam headlamps will not operate.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, scan tool disconnected, all doors closed, all accessories OFF, open and close the drivers door, disconnect the harness connector at the S78 Turn Signal/Multifunction Switch. It may take up to 10 minutes for all vehicle systems to power down.
  2. Test for less than 5 ohms between the ground circuit terminal 6 and ground. If 5 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Ignition ON.
  4. Verify the scan tool High Beam Select Switch parameter is Inactive. If not Inactive Ignition OFF, disconnect the X3 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 11 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  5. Install a 3 A fused jumper wire between the signal circuit terminal 11 and ground.
  6. Verify the scan tool High Beam Select Switch parameter is Active. If not Active Ignition OFF, disconnect the X3 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the signal circuit terminal 11 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  7. Test or replace the S78 Turn Signal/Multifunction Switch.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Turn Signal Switch Replacement»(/cadillac/ats/i-2012-2014/remont/steering-column-switches/#steering-wheel-and-steering-column)
  2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Turn Signal/Multifunction Switch Headlamps OFF SignalB257A 0011
Turn Signal/Multifunction Switch Headlamps ON SignalB257A 0011
Turn Signal/Multifunction Switch Park Lamps ON Signal2B257A 002
Turn Signal/Multifunction Switch Flash To Pass SignalB3806 0011
Turn Signal/Multifunction Switch High Beam SignalB3650 0811
Turn Signal/Multifunction Switch Ground1
1. Headlamps Malfunction 2. Park, License, and/or Tail Lamps Malfunction

When the turn signal/multifunction switch is momentarily placed in the flash to pass position, ground is applied to the body control module (BCM) through the flash to pass signal circuit. The BCM responds to the flash to pass request by applying ground to the high beam relay control circuit which energizes the high beam relay. With the high beam relay energized, the switch contacts close allowing battery voltage to flow through the high beam fuses to the high beam control circuits illuminating the high beam headlamps. The high beam headlamps will only illuminate for as long at the flash to pass switch is activated.

Battery voltage must be between 9-16 V.

The BCM detects a short to ground in the turn signal/multifunction switch flash to pass signal circuit.

The high beam lamps and the high beam indicator on the instrument panel cluster are always ON.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, scan tool disconnected, all doors closed, all accessories OFF, open and close drivers door, disconnect the harness connector at the S78 Turn Signal/Multifunction Switch. It may take up to 10 minutes for all vehicle systems to power down.
  2. Test for less than 5 ohms between the ground circuit terminal 6 and ground. If 5 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Ignition ON.
  4. Verify the scan tool Headlamps Flash Switch parameter is Inactive. If not Inactive Ignition OFF, disconnect the X3 harness connector at the K9 Body Control Module. Test for infinite resistance between the signal circuit terminal 12 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K9 Body Control Module. If Inactive
  5. Install a 3 A fused jumper wire between the signal circuit terminal 12 and ground.
  6. Verify the scan tool Headlamps Flash Switch parameter is Active. If not Active Ignition OFF, disconnect the X3 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the signal circuit terminal 12 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If Active
  7. Test or replace the S78 Turn Signal/Multifunction Switch.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Turn Signal Switch Replacement»(/cadillac/ats/i-2012-2014/remont/steering-column-switches/#steering-wheel-and-steering-column)
  2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Turn Signal Multifunction Switch Park Lamps ON Signal2B257A 002
License Plate Lamp ControlB3883 02B3883 04B3883 01
Rear Tail Lamp Control - LeftB3881 0211
Rear Tail Lamp Control - RightB3882 0211
Turn Signal Multifunction Switch Ground2
Rear Tail Lamp Ground - Left1
Rear Tail Lamp Ground - Right1
1. Park, License, and/or Tail Lamps Malfunction 2. Park Lamp Switch Malfunction

When the headlamp switch is placed in the HEAD or PARK position, ground is applied to the park lamp switch ON signal circuit to the body control module (BCM). The BCM responds by applying voltage to the park lamps, tail lamps, and license lamps control circuits illuminating the park, tail, and license lamps.

  1. Battery voltage must be between 9-16 V.
  2. Park lamps ON.

DTC B3881 02

The BCM detects a short to ground in the left rear tail lamp control circuit.

DTC B3882 02

The BCM detects a short to ground in the right rear tail lamp control circuit.

The appropriate tail lamp will not operate.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

DTC B3881

  1. Ignition OFF, exterior lamps OFF, trunk latch latched, disconnect the harness connector at the appropriate park/side marker lamp - left.
  2. Test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground. E2LF side marker lamp - left front terminal 1 E5E tail lamp - left terminal 5 E13L headlamp - left terminal 3 If 5 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the appropriate control circuit terminal listed below and ground, ignition ON. E2LF side marker lamp - left front terminal 2 E5E tail lamp - left terminal 1 E13L headlamp - left terminal 7 - with TR6 E13L headlamp - left terminal 6 - with TUJ
  4. Verify the test lamp turns ON and OFF when commanding the Left Park Lamps ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X4 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Ignition OFF, disconnect the X4 harness connector at the K9 body control module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the appropriate park/side marker lamp - left.

DTC B3882

  1. Ignition OFF, exterior lamps OFF, trunk latch latched, disconnect the harness connector at the appropriate park/side marker lamp - right.
  2. Test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground. E2LF side marker lamp - left front terminal 1 E5E tail lamp - right terminal 5 E13L headlamp - right terminal 3 If 5 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the appropriate control circuit terminal listed below and ground, ignition ON. E2LF side marker lamp - right front terminal 2 E5E tail lamp - right terminal 1 E13L headlamp - right terminal 7 - with TR6 E13L headlamp - right terminal 6 - with TUJ
  4. Verify the test lamp turns ON and OFF when commanding the Right Park Lamps ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X4 harness connector at the K9 body control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 body control module. If the test lamp is always ON Ignition OFF, disconnect the X4 harness connector at the K9 body control module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 body control module. If the test lamp turns ON and OFF
  5. Test or replace the appropriate park/side marker lamp - right.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Tail Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Front Side Marker Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  3. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
F8DA (BCM 1) Fuse B+B1325 03, B3265 01, B3265 04, B3873 01, B3873 04, B3883 01, B3883 04, C0297 01B1325 03, B3265 01, B3265 04, B3873 01, B3873 04, B3883 01, B3883 04, C0297 01
License Plate Lamp ControlB3883 02B3883 01, B3883 04B3883 01, B3883 04
License Plate Lamp Ground - RightB3883 01, B3883 04
License Plate Lamp Ground - LeftB3883 01, B3883 04

When the turn signal/multifunction switch is placed in the HEAD or PARK position, ground is applied to the park lamp switch ON signal circuit to the body control module (BCM). The BCM responds by applying voltage to the park lamps, tail lamps, and license lamps control circuits illuminating the park, tail, and license lamps.

Battery voltage must be between 9-16 V.

DTC B3883 01

Turn signal/multifunction switch in OFF position.

DTC B3883 02 or B3883 04

Turn signal/multifunction switch in AUTO, PARK or ON positions.

DTC B3883 01 and DTC B3883 04

  1. The BCM detects a short to voltage or an open/high resistance in the license lamps control circuit.
  2. The BCM detects a short to ground or an open/high resistance in the F8DA (BCM 1) fuse B+ circuit.
  3. The BCM detects an open/high resistance in the license lamps ground circuit.

DTC B3883 02

The BCM detects a short to ground in the license lamps control circuit.

DTC B3883 01

License lamps always ON.

DTC B3883 02 or B3883 04

License lamps inoperative.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

  1. «Exterior Lights Schematics»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-schematic-wiring-diagrams)
  2. «Body Control System Schematics»(/cadillac/ats/i-2012-2014/remont/communication-devices/#data-communication-system)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, exterior lamps OFF, remove both E7 License Plate Lamp bulbs.
  2. Test for less than 5 ohms between each ground circuit terminal 2 and ground. If 5 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the E7L License Plate Lamp - Left control circuit terminal 1 and ground, ignition ON.
  4. Verify the test lamp turns ON and OFF when commanding the License Plate Lamps ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  5. Ignition OFF.
  6. Connect a test lamp between the E7R License Plate Lamp - Right control circuit terminal 1 and ground, ignition ON.
  7. Verify the test lamp turns ON and OFF when commanding the License Plate Lamps ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If the test lamp turns ON and OFF
  8. Test or replace the appropriate E7 License Plate Lamp bulb.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Rear License Plate Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Rear License Plate Lamp Bulb Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  3. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Center High Mounted Stop Lamp ControlB3884 0211
Center High Mounted Stop Lamp Ground1
1. Stop Lamps Malfunction

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5 V reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the right and left stop lamp control circuits, engine control module (ECM), and center high mounted stop lamp control circuit.

  1. Battery voltage must be between 9-16 V.
  2. Brakes APPLIED.

The BCM detects a short to ground in the center high mounted stop lamp control circuit.

The BCM will not illuminate the center high mounted stop lamp.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, exterior lamps OFF, trunk latch latched, disconnect the harness connector at the E6 Center High Mounted Stop Lamp.
  2. Test for less than 5 ohms between the ground circuit terminal B and ground. If 5 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the control circuit terminal A and ground, ignition ON.
  4. Verify the test lamp turns ON and OFF when commanding the Center Brake Lamp ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp is always ON Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If the test lamp turns ON and OFF
  5. Test or replace the E6 Center High Mounted Stop Lamp.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «High Mount Stop Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Trailer Tail Lamp Control - LeftB3885 02B3885 041
Trailer Tail Lamp Control - RightB3886 02B3886 041
1. Trailer Lamps Malfunction

The trailer lighting control module receives a serial data message from the body control module (BCM) indicating that the vehicle park lamps have been activated. The trailer lighting control module responds by applying battery voltage to the left and right trailer tail lamp control circuits illuminating the trailer tail lamps.

  1. Battery voltage must be between 9-16 V.
  2. Park lamps ON.

DTC B3885 02

The trailer lighting control module detects a short to ground in the left trailer tail lamp control circuit.

DTC B3885 04

The trailer lighting control module detects an open/high resistance in the left trailer tail lamp control circuit.

DTC B3886 02

The trailer lighting control module detects a short to ground in the right trailer tail lamp control circuit.

DTC B3886 04

The trailer lighting control module detects an open/high resistance in the right trailer tail lamp control circuit.

The appropriate trailer tail lamp will be inoperative.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

DTC B3885

  1. Ignition OFF.
  2. Connect a test lamp between the left trailer tail lamp control circuit (5184 BN/GY) at the W8 Blunt Cut Trailer Provision and ground, ignition ON.
  3. Verify the test lamp turns ON and OFF when commanding the Left Trailer Tail Lamp ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X1 harness connector at the K68 Trailer Lighting Control Module. Test for infinite resistance between the control circuit terminal and ground. If less than infinite resistance, repair the short to ground on the circuits. If infinite resistance Test for less than 2 ohms in the control circuits end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K68 Trailer Lighting Control Module. If the test lamp is always ON Ignition OFF, disconnect the X1 harness connector at the K68 Trailer Lighting Control Module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K68 Trailer Lighting Control Module. If the test lamp turns ON and OFF
  4. Test or replace the W8 Blunt Cut Trailer Provision.

DTC B3886

  1. Ignition OFF.
  2. Connect a test lamp between the right trailer tail lamp control circuit (5185 GY) at the W8 Blunt Cut Trailer Provision and ground, ignition ON.
  3. Verify the test lamp turns ON and OFF when commanding the Right Trailer Tail Lamp ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X1 harness connector at the K68 Trailer Lighting Control Module. Test for infinite resistance between the control circuit terminal and ground. If less than infinite resistance, repair the short to ground on the circuits. If infinite resistance Test for less than 2 ohms in the control circuits end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K68 Trailer Lighting Control Module. If the test lamp is always ON Ignition OFF, disconnect the X1 harness connector at the K68 Trailer Lighting Control Module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K68 Trailer Lighting Control Module. If the test lamp turns ON and OFF
  4. Test or replace the W8 Blunt Cut Trailer Provision.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for trailer lighting control module replacement, programming, and setup

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Trailer Turn Signal Control - LeftB3887 02B3887 041
Trailer Turn Signal Control - RightB3888 02B3888 041
1. Trailer Lamps Malfunction

The trailer lighting control module receives a serial data message from the body control module (BCM) indicating that the vehicle left or right turn signal lamp has been activated. The trailer lighting control module responds by applying a pulsating voltage to the appropriate trailer turn signal lamp through their respective control circuit illuminating the desired trailer turn signal lamp.

  1. Battery voltage must be between 9-16 V.
  2. Turn Signal ACTIVE.

DTC B3887 02

The trailer lighting control module detects a short to ground in the left trailer turn signal control circuit.

DTC B3887 04

The trailer lighting control module detects an open/high resistance in the left trailer turn signal control circuit.

DTC B3888 02

The trailer lighting control module detects a short to ground in the right trailer turn signal control circuit.

DTC B3888 04

The trailer lighting control module detects an open/high resistance in the right trailer turn signal control circuit.

The appropriate trailer turn signal lamp will be inoperative.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

DTC B3887

  1. Ignition OFF.
  2. Connect a test lamp between the left trailer turn signal control circuit (5186 BU/WH) at the W8 Blunt Cut Trailer Provision and ground, ignition ON.
  3. Verify the test lamp turns ON and OFF when commanding the Left Trailer Turn Signal Lamp ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X1 harness connector at the K68 Trailer Lighting Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K68 Trailer Lighting Control Module. If the test lamp is always ON Ignition OFF, disconnect the X1 harness connector at the K68 Trailer Lighting Control Module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K68 Trailer Lighting Control Module. If the test lamp turns ON and OFF
  4. Test or replace the W8 Blunt Cut Trailer Provision.

DTC B3888

  1. Ignition OFF.
  2. Connect a test lamp between the right trailer turn signal control circuit (5187 N.mE/GY) at the W8 Blunt Cut Trailer Provision and ground, ignition ON.
  3. Verify the test lamp turns ON and OFF when commanding the Right Trailer Turn Signal Lamp ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X1 harness connector at the K68 Trailer Lighting Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K68 Trailer Lighting Control Module. If the test lamp is always ON Ignition OFF, disconnect the X1 harness connector at the K68 Trailer Lighting Control Module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K68 Trailer Lighting Control Module. If the test lamp turns ON and OFF
  4. Test or replace the W8 Blunt Cut Trailer Provision.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for trailer lighting control module replacement, programming, and setup

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Stop Lamps/Center High Mounted Stop Lamp ControlB3884 02B3884 01, B3884 04B3884 01, B3884 04
Trailer Stop Lamp ControlB3889 02B3889 041
1. Trailer Lamps Malfunction

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5 V reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the stop lamps/center high mount stop lamp control circuit, engine control module (ECM), and trailer lighting control module. When the brakes are applied on the vehicle, the trailer lighting control module receives the brake applied input from the stop lamps/center high mount stop lamp control circuit. The trailer lighting control module responds by applying voltage to the trailer stop lamp control circuit illuminating the trailer stop lamps. The trailer lighting control module also receives a serial data message from the BCM indicating that the vehicle brakes have been applied.

  1. Battery voltage must be between 9-16 V.
  2. Brakes APPLIED.

DTC B3889 02

The trailer lighting control module detects a short to ground in the trailer stop lamp control circuit.

DTC B3889 04

The trailer lighting control module detects an open/high resistance in the trailer stop lamp control circuit.

The trailer stop lamps will be inoperative.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

  1. «Trailer Connector/Provision Schematics»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-wiring-schematics-and-wiring-harness-routing-diagrams)
  2. «Exterior Lights Schematics»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-schematic-wiring-diagrams)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF.
  2. Connect a test lamp between the trailer stop lamp control circuit (5188 BN/YE) at the W8 Blunt Cut Trailer Provision and ground, ignition ON.
  3. Verify the test lamp turns ON and OFF when commanding the Trailer Brake Lamps ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X1 harness connector at the K68 Trailer Lighting Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K68 Trailer Lighting Control Module. If the test lamp is always ON Ignition OFF, disconnect the X1 harness connector at the K68 Trailer Lighting Control Module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K68 Trailer Lighting Control Module. If the test lamp turns ON and OFF
  4. Test or replace the W8 Blunt Cut Trailer Provision.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for trailer lighting control module replacement, programming, and setup

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Secondary Left Tail and Brake Lamp ControlB388B 02B388B 04
Secondary Right Tail and Brake Lamp ControlB388C 02B388C 04

When the headlamp switch is placed in either the park or low beam position, ground is applied to the tail lamp signal circuit to the body control module (BCM). The brake pedal position sensor provides an analog voltage signal to the BCM. The BCM sends this messages to the trailer lighting converter. The trailer lighting converter responds by applying battery voltage to the left tail lamp and to the right tail lamp control circuits. This energizes the tail lamps.

  1. Battery voltage must be between 9-16 V.
  2. Brake/tail lamp ON.

DTC B388B 02

The trailer interface control module detects a short to ground in the secondary left tail and brake lamp control circuit.

DTC B388B 04

The trailer interface control module detects an open in the secondary left tail and brake lamp control circuit.

DTC B388C 02

The trailer interface control module detects a short to ground in the secondary right tail and brake lamp control circuit.

DTC B388C 04

The trailer interface control module detects an open in the secondary right tail and brake lamp control circuit.

The appropriate brake/tail lamp is inoperative.

  1. The condition responsible for setting the DTC no longer exists and the ignition is cycled.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, exterior lamps OFF, disconnect the appropriate harness connector listed below. E56L Rear Multifunction Carrier Tail Lamp Assembly - Left E56R Rear Multifunction Carrier Tail Lamp Assembly - Right
  2. Test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground. E56L Rear Multifunction Carrier Tail Lamp Assembly - Left terminal C E56R Rear Multifunction Carrier Tail Lamp Assembly - Right terminal B If 5 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
  3. Connect a test lamp between the appropriate control circuit terminal listed below and ground, ignition ON E56L Rear Multifunction Carrier Tail Lamp Assembly - Left terminal B E56R Rear Multifunction Carrier Tail Lamp Assembly - Right terminal C
  4. Verify the test lamp turns ON and OFF when commanding the appropriate Auxiliary Tail and Brake Lamp test with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the X1 harness connector at the K101 Trailer Interface Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K101 Trailer Interface Control Module. If the test lamp is always ON Ignition OFF, disconnect the X1 harness connector at the K101 Trailer Interface Control Module, ignition ON. Test for less than 1 V between the control circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K101 Trailer Interface Control Module. If the test lamp turns ON and OFF
  5. Test or replace the appropriate E56 Rear Multifunction Carrier Tail Lamp Assembly.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Tail Lamp Replacement»(/cadillac/ats/i-2012-2014/remont/exterior-lights/#lighting-system-repair-instructions)
  2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or Trailer Interface Control Module replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Trailer Lighting Control Module B+11
Trailer Connected Position Switch Signal1B388D 05B388D 05
Trailer Lighting Control Module Ground1
Trailer Connector Grounds1
1. Trailer Lamps Malfunction

The trailer lighting control module is supplied with battery voltage as well as ignition voltage from the rear body fuse block and is permanently grounded. For lighting operation, the trailer lighting control module receives serial data messages from the body control module (BCM) indicating what lamps have been activated on the vehicle. The trailer lighting control module responds by applying voltage to the appropriate control circuits for the requested lamps illuminating the lamps on the attached trailer.

  1. Battery voltage must be between 9-16 V.
  2. Ignition ON.
  3. Trailer connected.

The trailer lighting control module detects a short to voltage or an open/high resistance in the trailer connected position switch signal circuit.

  1. The condition responsible for setting the DTC no longer exists and the ignition is cycled.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, test for 4.8-5.2 V between the trailer connector position switch signal circuit (5992 GN/BU) at the W8 Blunt Cut Trailer Provision and ground. If less than 4.8V Ignition OFF, disconnect the X1 harness connector at the K68 Trailer Lighting Control Module. Test for infinite resistance between the signal circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K68 Trailer Lighting Control Module. If greater than 5.2 V Ignition OFF, disconnect the X1 harness connector at the K68 Trailer Lighting Control Module, ignition ON. Test for less than 1 V between the signal circuit terminal and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K68 Trailer Lighting Control Module. If between 4.8-5.2 V
  2. Test or replace the W8 Blunt Cut Trailer Provision.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for trailer lighting control module replacement, programming, and setup

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Trailer Connector/Provision Schematics
• Exterior Lights Schematics
• COMPONENT CONNECTOR END VIEWS - INDEX
• Exterior Lighting Systems Description and Operation
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Diagnostic Repair Verification
• High Mount Stop Lamp Replacement
• Interior Lighting Systems Description and Operation
• Front Compartment Fuse Block Housing Replacement
• Body Control System Schematics
• Turn Signal Switch Replacement
• Relay Replacement (Within an Electrical Center)
• Door Lock Switch Replacement - Driver Side
• Sun Load Temperature Sensor Replacement
• Electronic Suspension Front Position Sensor Replacement

More articles — Lighting