Pinpoint Test Aa: DTC B1A98:88
WARNING: This page is about a different car, the 2010 Mercury Milan, 2010 Lincoln MKZ, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
- AA1 ISOLATE THE LH HEADLAMP ASSEMBLY AS THE CAUSE OF THE DTC
- Ignition OFF.
- Disconnect: LH Headlamp Assembly C1021.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: HCM Self-Test.
- Clear the DTCs and repeat the HCM self-test.
- Is DTC B1A98:88 still present? NOTE: Other DTCs can be present with the headlamp assembly disconnected and should be ignored.
- Yes: GO to AA2.
- No: INSTALL a new LH headlamp assembly. REFER to Removal and Installation . CLEAR the DTCs. REPEAT the self-test.
- AA2 ISOLATE THE RH HEADLAMP ASSEMBLY AS THE CAUSE OF THE DTC
- Ignition OFF.
- Disconnect: RH Headlamp Assembly C1041.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: HCM Self-Test.
- Clear the DTCs and repeat the HCM self-test.
- Is DTC B1A98:88 still present? NOTE: Other DTCs can be present with the headlamp assembly disconnected and should be ignored.
- Yes: GO to AA3.
- No: INSTALL a new RH headlamp assembly. REFER to Removal and Installation . CLEAR the DTCs. REPEAT the self-test.
- AA3 CHECK THE COMMUNICATION CIRCUITS TO THE HEADLAMPS FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: HCM C1600.
- Ignition ON.
- Measure the voltage between the HCM C1600-17, circuit VLF32 (YE), harness side, and ground; and the HCM C1600-18, circuit VLF33 (BU), harness side, and ground.
- Is any voltage present?
- Yes: REPAIR circuit VLF32 (YE) (LH headlamp) or circuit VLF33 (BU) (RH headlamp) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
- No: GO to AA4.
- AA4 CHECK THE COMMUNICATION CIRCUITS TO THE HEADLAMPS FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the HCM C1600-17, circuit VLF32 (YE), harness side, and ground; and the HCM C1600-18, circuit VLF33 (BU), harness side, and ground.
- Is the resistance greater than 10,000 ohms?
- Yes: GO to AA5.
- No: REPAIR circuit VLF32 (YE) (LH headlamp) or circuit VLF33 (BU) (RH headlamp) for a short to ground. CLEAR the DTCs. REPEAT the self-test.
- AA5 CHECK FOR CORRECT HCM OPERATION
- Disconnect all the HCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the HCM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
- Yes: INSTALL a new HCM. REFER to Removal and Installation . TEST the system for normal operation.
- No: The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.