On-Car Exercise(ABS CHECK)



On-Car Exercises

Assigned to identify the following components to the tutor:

1 wheel speed sensor

This is an inductive type sensor locate at the left front wheel of this vehicle as you can see is not much room to measure an air cap, anyway we manage to get to the air cap and is 0.82mm depth match the spec. 

2 ABS Control unit. 3.ABS modulator. 4.ABS pump

Here we found a modulator, pump and ABS control unit which attach to one unit and located near close to the master cylinder for this vehicle.  

5. barking brake switch. 9. Foot brake switch

Number (5) shows for most vehicle normally located between the front seat to the driver, the brake switch is attach to the handle under the frame. Some automatic transmission used the foot pedal instead of hand to apply this brake. Now number (9) indicate the foot brake switch for this vehicle.

6. Brake master cylinder. 7 Brake fluid level switch. 10 Brake booster

This is a tendem master cylinder and is bolt to the brake booster which is normally locate under the dash-board next to the driver's lower side connect to the brake pedal. 'The brake booster of this vehicle is shows on the white mark (number 10) It helps the driver to compress and release pressure. 

8. RPM Sensor

The sensor mounted to the engine crank attach to the pully, position to the ring teeth of the crankshaft. most vehicle these days have their RPM sensor operate inside the ignition distributor (inductive type) giving out analogue signals.(AC)

 

11 ABS control unit fuse

This is the Fusible link where ABS modulator relay, pump relay, fuses and other connector are located, inside a small fuse box. the box cover give the instruction so we can locate them. 

Front / Rear Wheel Speed Sensor Located.

Front Right - 0.82mm      Front Left - 0.335mm

This vehicle fitted with ABS system, we also identify and located each component. The wheel sensor used is inductive type (magnetic/pulse generator) reads analogue signals.

Rear Wheel Speed Sensor

In this vehicle both rear are drum brakes, and with the wheels speed sensor mounted inside the rear drums we could not reach to the point where we can measure the air cap.

2: sensor 1: ring teeth

Analogue test using an oscilloscope

Voltage 0.5v/div. Time 5ms/div 

For this analogue signal we need 15kM/H or 20KM?H for the inductive type sensor

Frequency: 115Hz at 15KM/H

If we can compare the frequency scale on multi-meter by turn the wheel toward speed of other result than it could be a closed result depend on the turning wheel. The multi-meter shows AC waveform change both frequency and voltage to increase and decrease rapidly. Low speed give a low voltage signal indicates slow in frequency, higher speed gives a higher voltage signal also indicate higher frequency.

Using a Scan Tool

 ABS live data at the engine's high speed

This recording data shows that all solenoids are in off position, battery voltage at14.64v and both (LF/RF) sensor are on 71 KPH with the engine at idle.

Current Data A

HYDRAULIC PUMP MOTOR	OFF
LF ABS IN VALV	OFF
LF ABS OUT VALV	OFF
LF WHEEL SPD SENS	71 KPH
LR ABS IN VALV	OFF
LR ABS OUT VALV	OFF
LR WHEEL SPD SENS	O KPH
RF ABS IN VALV	OFF
RF ABS OUT VALV	OFF
RF WHEEL SPD SENS	71 KPH

Current Data B 

Vehicle's hard braking (stop)

Current Data A

ABS VALV CTRL RELAY	ON
ABS WARN LAMP STATUS	ON
BAT POSITIVE VOLT	13.02
BRAKE SW IN	OFF
BREAK WARN LAMP STATE	ON
HYDRAULIC PUMP MOTOR	OFF
HYDRAULIC PUMP MOTOR	OFF
LF ABS OUT VALV	OFF
LF ABS OUT VALV	OFF
LF WHEEL SPD SENS	O KPH

Current Data B 

This live data show the hydraulic pump motor is switches off, while the ABS system is operating, one wheels shows is lock up this could switches on ABS control relay and relay pump motor. The problem we face with this vehicle is both rear wheel sensor give out fault to the scan. 

Actuator TEST

Testing our ABS pump we used the Autoboss tool, this activate the pump relay and solenoid even the vehicle is shot off. Giving demand or actuation on the scan tool is perfect way to check system, diagnoses and analyse other programs.

The test we working on today is to check the ABS actuator and see if it work. When we test solenoids we can hear the clicking sound once they activate, we used the scan tool to switch it on/off. when this happen the solenoid click and so they work. If the solenoid dosen't click than we can identify it as fault.

ON Car: Elecntronic trasmissions / Scan Tools

ElectronicTransmissions and Scan Tools

Vehicle Holden Year 2002 Engine

PCM: Powertrain Control Module

TCC: Torque Converter Clutch

TPS: Throttle Position Sensor

ECT: Engine Coolant Temperature

VSS: Vehicle Speed Sensor

PSA: Pressure Switch Assembly (Transmission Range Fluid)

TTS: Transmission Temperature Sensor

Block Diagram

Circuit Diagram of Power-train Control module System



Shift Solenoids Malfunction

When the vehicle is shifted into drive and starts on the first gear, shift solenoid all the solenoid are in-cage which mean its ON. If the transmission automatically shifts from first to second gear, this turn 1-2 OFF and switches 2-3 solenoid ON. Now when the transmission automatically shifts to third gear, both would not in-cate. and so the solenoid should be in OFF position this called fail safe. And last when automatic shifts into fourth gear, shift solenoid 1-2 is ON and 2-3 is OFF.

Safety Mode

In some case particularly when third gear automatically shift and where solenoid switch off, and the vehicle would still driving. Safety mode switches take place encase of something could go wrong. With the engine of six cylinder, the safety mode would turn both solenoid off at third gear and the vehicle would travel at about 40-30 km/h, but with the powerful engine, this would have the torque to climb up hill.

Codes: 

 DTC67: Torque converter clutch or QDM to circuit fault. There’s a fault in the circuit sensor

 DTC27: Transmission fluid pressure switch assembly open circuit

1st Problem Testing: Disconnect jumper harness from transmission than connect the end to the power-train harness turn on the ignition while using a multi-meter to check the voltage. This test shows to check power to the torque converter clutch solenoid.

2nd Problem Testing: Check for fluid lever and use the scan tool to identify the fault

On-Car Transmission Exercises

 Vehicle: Toyota Motor: 7A-FE 1.8L Year 1998

  Shift chart:

Solenoids (gear)	O/D Turn OFF	O/D Turn ON
First gear Solenoids	OFF (Lock up solenoid)	OFF
Second gear solenoids	OFF	OFF
Third gear Solenoids	ON (Lock up solenoid) at 2850RPM	OFF
Fourth gear solenoids	OFF	ON at 1600rpm, solenoid SLU and Lock up solenoid)

O/D TURN OFF

With Overdrive switches OFF

The video show the transmission test with the O/D is switch off and the transmission can not shift to 4th gear because of torque and ratio (0.8 of 1). when the 3rd gear approach at about 2500rpm engine speed, the torque converter clutch lock up turns ON the solenoid and lock the turbine and flywheel. This is when the transmission catch up with engine speed. 

O/D TURNS ON

 The 4th gear is now activated and the clutch lock up solenoid switches at engine speed of 1600rpm.

Shift Chart

Controlled Area Network Board

ControlledArea Network Board
The Multiplexing Network is a digital communication between logic modules with only one or two data wires connected to all the modules. Modules are connected together in either series or parallel circuits. Used no sensors or actuators, and “Gateway” module would be one that can translate different speeds from one group to another.

COMMUNICATION WIRE: H-CAN and  L-CAN

A – (High) CAN -1     H CAN2 Blue

   B – (Low) CAN – 4    L CaN5 Yellow

The two wire CAN H and CAN L. For the CAN to communicate one is to pulls the voltage up to about 5v. The other pulls the connection to earth and as result the voltage is pulled up and down. This creates the language between the two wires (CAN)

No codes created (start to finish)



This shows protocol without code creates, both Low and High pattern has not switch on or disturbing the signal. Looking at the pattern the two wires mirror each other equally. One is slightly higher than the other.

Describe the relationship between the two patterns and their base voltages (what volts when not switched)

Both wire share the minimum of 5volts. The two patterns are communicates by (talk) toggling the voltage up and down in digital language.

For each of the following inputs capture the pattern and identify were it changes in relation to the original pattern:

 right indicator

We started with sending a code through the node to communication wire, as the right indicator switches on the signal pattern made the change. The green circle known as Low voltage wire show more speed than the High signal wire (red circle).

left indicator

The left indicator we suggest that both right and left code give different code and the picture shows is the opposite of the right indicator

rear wiper

Our next code is rear wiper when this switch on, the metal plate which attach to a wiper motor start to turn. If we look close at the pattern of this signal communication the two wire change at the end of the frame. As you can see on the drawing this indicate the different between the two pattern.

stop-light

As the code is transfer from one node to another the brake light comes on and the pattern signal message change from these location. Multiplex in brake light circuit are wired to the nearest module that gets a message from another module (cem), that gets a request from a switch, and turning the brake light on.

fuel pump

The lights turn on and the fuel pump is working. We show some digital give small change in this frame, but not much of a code which is respond to connection wires. 

Reverse lights

When the reverse light switches on the request code is determine by the nodes, where the message is than translate and deliver through CAN.

Using the wiring diagram and CAN board Identify the input /output pins, wire colour, Relay or transistor for the right hand indicator and rear wiper:

Right Indicator: (INPUT) Pin #7 = (Zener diode) Pin #6 = (output) IC9 = (A) Relay 18F258

Rear Wiper: (ground) Pin #9 and Pin #8 to Pin #25 (RB4/18F258) =314

(Output) Pin #GP6 = Pin #10 – (Resistor) 35 – (Transistor) BC547 –

Using the wiring diagram identify both voltage regulators that resemble the one that you built in TTEC4824. Note all the input pins and were the outputs are connected to

1 UI 7805: Input (supply voltage) Pin #1 and Pin #2

2 VI U2+5v (7805 GND): Output C18/0.luf Capacitor to Pin #14VDD