Possible Causes

WARNING: This page is about a different car, the 2020 Lincoln Navigator. However, it is still accessible from the selected car via links, so may be relevant.

Wiring, terminals or connectors
HydroMax pump motor relay
ABS module

Fig 1: Antilock Braking System (ABS) Module Connector - C135

Courtesy of FORD MOTOR CO.

Harness Side

Circuit

CU1: CHECK PUMP MOTOR RELAY COIL GROUND CIRCUIT FOR AN OPEN

Ignition OFF.
ABS Module connector disconnected. (C135)
Hydraulic Fluid Flow Switch connector disconnected.
HydroMax Relay connector disconnected.

Measure the resistance between:

(+) Hydraulic Fluid Flow Switch Connector, Harness Side	(-) ABS Module (C135) Connector, Harness Side
HRC	HRC

Measure the resistance between:

(+) Hydraulic Fluid Flow Switch Connector, Harness Side	(-) HydroMax Relay Connector, Harness Side
HRC	HRC

Are the resistances less than 3 ohms?

Yes	No
Go to CU2.	REPAIR the circuit.

CU2: CHECK PUMP MOTOR RELAY COIL GROUND CIRCUIT FOR A SHORT TO GROUND

Measure the resistance between:

(+) HydroMax Relay Connector, Harness Side	(-)
HRC	Ground

Is the resistance greater than 10, 000 ohms?

Yes	No
Go to CU3.	REPAIR the circuit.

CU3: CHECK PUMP MOTOR RELAY COIL GROUND CIRCUIT FOR A SHORT TO VOLTAGE

Ignition ON, engine OFF.

Measure the voltage between:

(+) HydroMax Relay Connector, Harness Side	(-)
HRC	Ground

Is any voltage present?

Yes	No
REPAIR the circuit.	Go to CU4.

CU4: CHECK FOR CORRECT ABS MODULE OPERATION

Ignition OFF.
Inspect the ABS module electrical connector and the HydroMax relay socket.
Repair:
- corrosion (install new connector, socket or terminal - clean module or relay pins)
- damaged or bent pins - install new terminals or pins
- pushed-out pins - install new pins as necessary
ABS Module connector connected. (C135) Make sure the connector seats and latches correctly.
Hydraulic Fluid Flow Switch connector connected. Make sure the connector seats and latches correctly.
HydroMax Relay connector connected. Make sure the relay is fully seated.
Operate the system and determine if the concern is still present.
Is the concern still present?

Yes	No
INSTALL a new ABS module. CHECK OASIS for any applicable service articles; TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new ABS module. REFER to the Anti-Lock Brake System (ABS) and Stability Control article. ORDER a replacement ABS module and INCLUDE the RVC on the order form. If this is a Ford paid repair, INCLUDE the RVC on the warranty form.	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.

Yes

INSTALL a new ABS module.
CHECK OASIS for any applicable service articles; TSB, GSB, SSM or FSA.
If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions.
If no service articles address this concern, INSTALL a new ABS module. REFER to the Anti-Lock Brake System (ABS) and Stability Control article.
ORDER a replacement ABS module and INCLUDE the RVC on the order form.
If this is a Ford paid repair, INCLUDE the RVC on the warranty form.

The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.