ABS Relays

Record the name of the relay or switch that power up the ABS : K 38
Record the name of the relay or switch that powers up the ABS: K100
Record the name of relay or switch that send power to the ABS HCU solenoid: K39


Relay wire identification:
What is the ECU pin number for the wire that brings in the power to the ABS ECU? 25, 24
What is the ECU pin number, or other number for the wire that control the relay for the ABS ECU? K39
What is the pin number for the wire that bring in the power to the ABS pump? 30

ABS Demonstrators

Wiring diagram for your demonstrator vehicle. Find ABS wheel speed sensor pin out connection to the ECU on the wiring diagram and the demonstrator. Record which ECU wires go to wich wheel speed sensors:

Left front  ECU Pin # 4 and 5
Left rear   ECU Pin # 7 and 9
Right front ECU Pin # 11 and 21
Right rear  ECU Pin # 24 and 26

What type of speed sensor is this ?  Permanent magnet coil type sensor.


Describe how it works?
A toothed ring on the wheel when rotates a magnetic pick up has magnetic which has reluctance as the magnet is near or far from, in the teeth of ring iron makes the magnetic field stronger and weaker.


Located an oscilloscope. Turn it on and set it up to be fully operational. What oscilloscope are you using?
Tektronix TDS 100 IB two Chanel oscilloscope.


Record a waveform for each wheel speed sensor in the boxes below. Note voltage per division and per division for each.

Which wheels is this? Left front

Which wheel is this? Left rear.

Which wheel is this? Rear right.

Which wheel is this? Rear left.

Are all the waveforms exactly the same? NO The rear right wheel waveform is different, we seat the the oscilloscope 2.0 v and 250 us for one devision. The wave form of rear right wheel low spike voltage the cause is the sensor will be far from the tooth wheel , dirty sensor or may be when i toke the picture the speed of wheel is low.

With the wheel speed sensors sniping, measure AC volts with multi - meter and record here:

Left front  3.66           pin# B19

Left rear  2.61 V            Pin # B21

Right front  4.41 V            Pin # B 20

Rear right  4.91 V                 Pin # B22

Can a multi-meter be as accurate in finding problems wthe the wheels speed sensors as an oscilloscope? YES

Digital signal

On the graph draw a digital signal that switches 5 volts every 2 second.

On the graph below draw an analogue signal with frequency of 0.5 Hz and maximum of +3 volts.

ABS ( ANTI - LOCK BRAKE SYSTEM FOR FORD RHD)

Wiring Diagram Practice 

Using the wiring diagram in the workshop manuals identify the wheel speed sensors and list their wire colors for each sensor

B = BLACK                                  L = BLUE                                    R = RED

BR =BROWN                               LG = LIGHT GREEN               V = VIOLET

G = GREEN                                  O = ORANGE                            W = WHITE

GR = GRAY                                  P = PINK                                     Y = YELLOW

Front right + Black - White

Front left   + Red   -  Green

Rear left    + Blue -   Pink

Rear right  + Yellow _ Brown

On the ABS sensor what is the reason for the braded wire?

The reason for the braded wire or shielding for protection from radio interference or back EMF.

Identify and lest the fuses that are used by ABS circuit

F14, 4 IF1, 17 3A , 19 

Identify the earth for the ABS control unit and ABS motor their wire colors what pins numbers

ABS control unit W-B (L/B) and pin number is 7B , and 10B

ABS motor earth color is W - B , and 1A

On the wring diagram for the ABS actuator , identify which solenoids control which wheel cylinder.

Then note the wire colors and pin numbers.

Front Right wheel            Pin number 5B

                                          Wire color  L _ R

Front Left Wheel              Wire color  L - R

                                           Pin number  1A

Rear Left Wheel              Pin number  12B

                                          Wire color   BR - W

Rear Right Wheel           pin number  15A

                                         Wire color   G - Y

Using the next picture as guide, which of the foll wing gives the correct condition of the inlet and outlet solenoids valves under normal braking?

A: wrong Inlet vole open            outlet valve Open

B: correct Inlet valve open         outlet closed 

C: wrong  Inlet valve closed        outlet valve closed

D: wrong Inlet valve closed         outlet valve closed

Using the picture, which of the following gives the correct condition of the inlet and outlet solenoid valves when the ABS is operating to reduce wheel brake pressure?

A: wrong  Inlet valve en             outlet valve open

B: wrong  Inlet valve open         outlet valve closed

C: correct Inlet valve closed      outlet valve open

D: wrong  Inlet valve closed       outlet valve closed

Using the picture, which of the following gives the correct condition of the inlet and outlet solenoids valves when the ABS is operating to hold brake pressure?

A: wrong Inlet valve open          outlet valve open 

B: wrong Inlet valve open        outlet valve close

C: wrong Inlet valve closed     outlet valve open

D: correct Inlet valve closed      outlet valve closed

Using the picture which of the following gives the correct condition of the inlet and outlet solenoid valves when the ABS is operating to increase wheel brake pressure?

A: wrong Inlet valve open         outlet valve open 

B: correct Inlet valve open        outlet valve closed

C: wrong Inlet valve closed       outlet valve open 

D: wrong Inlet valve closed       outlet valve closed

In the four cases above state when the ABS motor will be working?

The ABS will be working in these four cases gets hold pressure, reduce pressure, increase pressure,,in the brake system.

                                          

ABS Wiring and Operation

Lets review the ABS system to remind ourselves what components are included and how they should work.

Fill in the blanks with the name of the part:

1 = Brake disc
2 = Speed sensor
3 = Pulse ring
4 = Hydraulic Control Unit (HCU)
5 = Master cylinder
6 = Caliper
7 = Brake booster

Antilock Braking System Lab Workbook (4825)

off-car Exercises
Think about ABS Repaire:

Some possible causes for demanding an ECU.

• Spiked by careless welding, i, e. MIG welding without disconecting the battery. True
• Obvious sign of mechanical damage to the to the encloser. False
• Encloser seal damaged and with obvious sign of water ingress. Tru

Often the ECU will be misdiagnosed as faulty, usually because the techician is inexperienced in faultfinding.

• Faults are much more likely to be with connections or sensors. True

Discuse how these ECU issues shold be incorpirated into diagnostic practices to test an ABS system:
When the ABS prrses the signal to determine, the acceleration and the slip of the whells.
Then control signal to the hydrolic moderator which brake pressure in the system. Vhecle use anti lock brake system monitor it self and if a fault will switched it off, and the ABS warning in the dashboard, will remine an in show that there is a fault in the system.