Pinpoint Test Aw: Brake Lining Wear Sensor Faults

Refer to HORN/CIGAR LIGHTER for schematic and connector information.

Normal Operation and Fault Conditions

The ABS module uses 2 normally-open switches, connected in series, to monitor the wear of the brake pads. As the brake pads wear, the switches close. Once fully closed, the ABS sends a message to the IPC to display a warning in the message center.

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
ABS C004A:13	Brake Lining Wear Sensor: Circuit Open	This DTC sets when the ABS detects an open circuit condition in the brake lining wear indicator circuit.

Possible Sources

Wiring, terminals or connectors
Brake pad wear indicator

NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.

AW1 CHECK THE ABS (ANTI-LOCK BRAKE SYSTEM) BRAKE LINING WEAR SENSOR CIRCUIT FOR AN OPEN

Ignition OFF.

Disconnect ABS connector, C135.

Disconnect Left Front Brake Pad Wear Indicator Switch connector, C1687.

Disconnect Left Rear Brake Pad Wear Indicator Switch connector, C4427.

Measure the resistance between:

Positive Lead	Measurement / Action	Negative Lead
C135 Pin 43	Courtesy of FORD MOTOR COMPANY	C4427 Pin 1

Is the resistance less than 3 Ohm?

Yes

GO to AW2

No	REPAIR the affected connectors or terminals. Refer to OEM ELECTRICAL WIRING DIAGRAM INTRODUCTION for schematic and connector information.

AW2 CHECK THE REAR SENSOR TO FRONT SENSOR CIRCUIT FOR AN OPEN

Measure the resistance between:

Positive Lead	Measurement / Action	Negative Lead
C4427 Pin 2	Courtesy of FORD MOTOR COMPANY	C1687 Pin 1

Is the resistance less than 3 Ohm?

Yes

GO to AW3

No	REPAIR the affected connectors or terminals. Refer to OEM ELECTRICAL WIRING DIAGRAM INTRODUCTION for schematic and connector information.

AW3 CHECK THE FRONT SENSOR GROUND CIRCUIT FOR AN OPEN

Measure the resistance between:

Positive Lead	Measurement / Action	Negative Lead
C1687 Pin 2	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance less than 3 Ohm?

Yes

GO to AW4

No	REPAIR the affected connectors or terminals. Refer to OEM ELECTRICAL WIRING DIAGRAM INTRODUCTION for schematic and connector information.

AW4 CHECK THE BRAKE LINING WEAR SENSORS FOR AN OPEN

Measure the resistance between:

Positive Lead	Measurement / Action	Negative Lead
C4427 Pin 1	Courtesy of FORD MOTOR COMPANY	C4427 Pin 2

Measure the resistance between:

Positive Lead	Measurement / Action	Negative Lead
C1687 Pin 1	Courtesy of FORD MOTOR COMPANY	C1687 Pin 2

Is the resistance less than 3 Ohm?

Yes

The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. INSPECT all disconnected electrical connectors for corrosion, spread terminals, pushed-out pins, damaged pins or bent pins. REPAIR as necessary. Refer to OEM CONNECTOR REPAIR PROCEDURES , for schematic and connector information.

Install a new brake lining wear indicator or indicators as necessary. REFER to: Brake Pads - Electric Motor (C0) . REFER to: Brake Pads - Vehicles With: Electronic Parking Brake (EPB) . REFER to: Brake Pads - Vehicles With: 2-Piston Brake Caliper . REFER to: Brake Pads - 5 Ton Vehicle, Vehicles With: Drum-in-Hat .