Visual Inspection and Diagnostic Pre-checks

WARNING: This page is about a different car, the 2019 Ford F-550 Super Duty, 2019 Ford F-450 Super Duty, 2019 Ford F-350 Super Duty, and 2019 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.

Make sure BJB fuse 22 (40A) and the fuse socket are OK.

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

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

Courtesy of FORD MOTOR COMPANY

Harness Side

Circuit

U1: DETERMINE VACUUM PUMP SYMPTOM

Ignition ON, engine running.
Allow the engine to run for at least 3 minutes to draw a vacuum in the brake booster.
Press and release the brake pedal at least 3 times to depelete the vacuum in the brake booster.
Listen to the vacuum pump and determine if it is running constantly or not running at all.
Is the vacuum pump running constantly?

Yes	No
Go to PINPOINT TEST V .	Go to U2.

U2: CHECK FOR DTC C0047:16, C0047:1C, C0047:1E OR C0047:64

Ignition ON, engine OFF.
Carry out the ABS self-test.
Is DTC C0047:16, C0047:1C, C0047:1E or C0047:64 present?

Yes	No
DIAGNOSE these DTCs first. Go to PINPOINT TEST C .	Go to U3.

U3: CHECK THE BRAKE VACUUM PUMP RELAY

Ignition OFF.
Remove the brake vacuum pump relay from the BJB.
Substitute a known good relay.
Apply the brake pedal several times to relieve the vacuum.
NOTE: Have an assistant listen for the vacuum pump to activate when the ignition is cycled ON.
Ignition ON, engine OFF.
Does the vacuum pump run when the ignition is cycled ON?

Yes	No
REMOVE the known good relay. INSTALL a new brake vacuum pump relay.	REMOVE the known good relay. Go to U4.

U4: CHECK FOR DTC P258A:14

Review the results from the ABS module self-test.
Is DTC P258A:14 present?

Yes	No
Go to U6.	Go to U5.

U5: CHECK THE BRAKE VACUUM PUMP RELAY CONTROL CIRCUIT FOR A SHORT TO VOLTAGE

Measure the voltage between:

(+) Vacuum Pump Relay Relay Connector, Harness Side	(-)
VPRC	Ground

Is any voltage present?

Yes	No
REPAIR the circuit.	Go to U6.

U6: CHECK THE BRAKE VACUUM PUMP RELAY CONTROL CIRCUIT FOR AN OPEN

Ignition OFF.
ABS Module connector disconnected. (C135)

Measure the resistance between:

(+) Vacuum Pump Relay Relay Connector, Harness Side	(-) ABS Module (C135) Connector, Harness Side
VPRC	VPRC

Is the resistance less than 3 ohms?

Yes	No
Go to U7.	REPAIR the circuit.

U7: CHECK THE BRAKE VACUUM PUMP RELAY OUTPUT CIRCUIT FOR AN OPEN

Vacuum Pump Motor connector disconnected.

Measure the resistance between:

(+) Vacuum Pump Relay Relay Connector, Harness Side	(-) Vacuum Pump Motor Connector, Harness Side
VPRO	VPRO

Is the resistance less than 3 ohms?

Yes	No
Go to U8.	REPAIR the circuit.

U8: CHECK THE BRAKE VACUUM PUMP RELAY OUTPUT CIRCUIT FOR A SHORT TO GROUND

Measure the resistance between:

(+) Vacuum Pump Motor Connector, Harness Side	(-)
VPRO	Ground

Is the resistance greater than 10, 000 ohms?

Yes	No
Go to U9.	REPAIR the circuit.

U9: CHECK THE BRAKE VACUUM PUMP GROUND CIRCUIT FOR AN OPEN

Measure the resistance between:

(+) Vacuum Pump Motor Connector, Harness Side	(-)
GND	Ground

Is the resistance less than 3 ohms?

Yes	No
Go to U10.	VERIFY the ground eyelet is clean and securely fastened. REFER to the Grounds Wiring Diagram article for ground information. CLEAN or TIGHTEN as necessary. If the ground eyelet is OK, REPAIR the circuit.

U10: CHECK THE BRAKE VACUUM PUMP RELAY SWITCHED VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

Measure the voltage between:

(+) Vacuum Pump Relay Relay Connector, Harness Side	(-)
B+	Ground

Is the voltage greater than 11 volts?

Yes	No
Go to U11.	REPAIR the circuit.

U11: CHECK THE BRAKE VACUUM PUMP RELAY COIL VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

Ignition ON, engine OFF.

Measure the voltage between:

(+) Vacuum Pump Relay Relay Connector, Harness Side	(-)
IGN START/RUN	Ground

Is the voltage greater than 11 volts?

Yes	No
Go to U12.	REPAIR the circuit.

U12: CHECK THE BRAKE VACUUM PUMP OPERATION

Ignition OFF.
Vacuum Pump Motor connector connected.
NOTE: It may be necessary to use a higher amperage fuse to activate the vacuum pump.

Connect a 5 amp fused jumper wire between the following:

Point A Vacuum Pump Relay Relay Connector, Component Side	Point B Vacuum Pump Relay Relay Connector, Component Side
B+	VPRO

Remove the fused jumper wire.
Does the brake vacuum pump run when the fused jumper wire is connected?

Yes	No
Go to U13.	INSTALL a new brake vacuum pump. REFER to the Removal and Installation procedure in the Anti-Lock Brake System (ABS) and Stability Control article.

U13: CHECK FOR CORRECT ABS MODULE OPERATION

Ignition OFF.
ABS Module connector disconnected. (C135)
Using a good light source, inspect all disconnected electrical connectors for the following:
- corrosion - install new connector or terminal and clean the module pins
- damaged or bent pins - install new terminals or pins
- pushed-out pins - install new pins as necessary
- spread terminals - install new terminals as necessary
ABS Module connector connected. (C135) Make sure the connector seats and latches correctly.
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, SSMs or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the TSB 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 form. If this is a Ford paid repair, INCLUDE the RVC on the warranty claim 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, SSMs or FSA.
If a service article exists for this concern, DISCONTINUE this test and FOLLOW the TSB 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 form.
If this is a Ford paid repair, INCLUDE the RVC on the warranty claim 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.