Pinpoint Tests

Daytime Running Lamps (DRL)

Pinpoint Tests

Pinpoint Test U: The Daytime Running Lamps (DRL) Are Inoperative

Normal Operation

When the ignition switch is in the RUN position, the headlamps are not on (from the autolamp system or manual control from the headlamp switch) and the transaxle is not in PARK (P), the Lighting Control Module (LCM) provides a pulse-width modulated voltage to the low beam headlamps. This illuminates the headlamps at a reduced intensity.

This pinpoint test is intended to diagnose the following:

- Exterior lighting system input/output
- LCM configuration
- Ignition switch input
- Transaxle gear input
- LCM


PINPOINT TEST U: THE DRL ARE INOPERATIVE

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U1 VERIFY THE DRL OPERATION


- Place the gear selector lever in any gear other than PARK (P).
- Are the DRL illuminated?

Yes
The system is operating correctly. INFORM the customer of the conditions required for the DRL to operate correctly.

No
GO to U2.

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U2 CHECK THE OPERATION OF THE HEADLAMPS


- Place the headlamp switch in the HEADLAMPS ON position and observe the headlamps.
- Do the headlamps operate correctly?

Yes
GO to U3.

No
REFER to Headlamps Special Tool(s) Used With Diagnostics.

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U3 CHECK THE IGNITION SWITCH INPUT


- Place the headlamp switch in the OFF position.
- Enter the following diagnostic mode on the scan tool: LCM DataLogger.
- Monitor the LCM ignition switch PIDs (IGN_LCM) while cycling the ignition switch through all positions.
- Does the PID agree with the ignition switch positions?

Yes
GO to U4.

No
REFER to Steering Column Switches Testing and Inspection to diagnose the input from the ignition switch.

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U4 CHECK THE TRANSAXLE GEAR INPUT


- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Monitor the PCM transmission gear status PID (TR) while placing the gear selector lever through all positions.
- Does the PID agree with the gear selection?

Yes
GO to U5.

No
REFER to Automatic Transaxle/Transmission - 4R70E/4R75E Testing and Inspection to diagnose the transmission range input.

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U5 CHECK THE LCM FOR DRL CONFIGURATION


- Enter the following diagnostic mode on the scan tool: LCM Module Programming.
- Check the LCM configuration and make sure the DRL feature is enabled.
- Is the LCM DRL configuration enabled?

Yes
INSTALL a new LCM. REFER to Multifunction Electronic Modules Lighting Control Module (LCM). TEST the system for normal operation.

No
ENABLE the DRL configuration. TEST the system for normal operation.

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