Oscilloscope waveform Types and interpretation

Prepared for

WIRE & GAS 2012 Training Convention

ACTIVITIES GROUP B

Sam Nazarian

Jack Stepanian

Long Reef Garage

All recorded measurements are believed to be true representation of and are based on unproblematic motor vehicle management. ALL rights are reserved to make changes without prior notice. ALL conditions prescribed under the copyright act are reserved. No

part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical without prior expressed written notice, it is an offence

For Circuit diagrams, connector Location/end views and pin configurations please see

TAT, Rellim Bookworks, Repco Auto Tech Encyclopedia, Auto Data, and Automotive Service Solution

Accompanied waveforms illustrated in these activities are captured with ‘Pico’ oscilloscope with varying time base and voltage scale settings

Prepared for WIRE & GAS 2012 Training Convention ACTIVITIES Group A – Oscilloscope waveform types & interpretation Authors: Sam Nazarian & Jack Stepanian

All Rights Reserved Long Reef Garage PTY LTD All recorded measurements are believed to be true representation of and are based on unproblematic motor vehicle management. ALL rights are reserved to make changes without prior

notice. ALL conditions prescribed under the copyright act are reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical without prior expressed written notice, it is an offence – All intellectual materials are the property of the authors.

For Circuit diagrams, connector Location/end views and pin configurations please see TAT, Relim Bookworks, Repco Auto Tech Encyclopedia, Auto Data, Automotive Service Solution

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Prepared for WIRE & GAS 2012 Training Convention ACTIVITIES Group A – Oscilloscope waveform types & interpretation Authors: Sam Nazarian & Jack Stepanian

All Rights Reserved Long Reef Garage PTY LTD All recorded measurements are believed to be true representation of and are based on unproblematic motor vehicle management. ALL rights are reserved to make changes without prior

notice. ALL conditions prescribed under the copyright act are reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical without prior expressed written notice, it is an offence – All intellectual materials are the property of the authors.

For Circuit diagrams, connector Location/end views and pin configurations please see TAT, Relim Bookworks, Repco Auto Tech Encyclopedia, Auto Data, Automotive Service Solution

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1 b - How to calibrate ‘Y’ axis

Whilst using channel A of the oscilloscope, connect

rechargeable battery across both terminals of the

oscilloscope wires (Red and Grey)

What setting must you have to ‘see’ the

accompanied waveform to the right?

X-axis / time base setting = ………milli second / Division

Y-axis / voltage scale =…………………volts / Division

1 a– How to calibrate ‘X’ axis

Start Pico Scope software

Familiarize yourself with X and Y axis

Hold active probe and observe waveform

Freeze frame by clicking on red and green buttons

(bottom left corner of screen)

Analyze snap frozen waveform

What setting must you have to ‘see’ the

accompanied waveform to the right?

X-axis / time base setting = ………milli second / Division

Y-axis / voltage scale =…………………volts / Division

Explain captured waveform……!

Prepared for WIRE & GAS 2012 Training Convention ACTIVITIES Group A – Oscilloscope waveform types & interpretation Authors: Sam Nazarian & Jack Stepanian

All Rights Reserved Long Reef Garage PTY LTD All recorded measurements are believed to be true representation of and are based on unproblematic motor vehicle management. ALL rights are reserved to make changes without prior

notice. ALL conditions prescribed under the copyright act are reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical without prior expressed written notice, it is an offence – All intellectual materials are the property of the authors.

For Circuit diagrams, connector Location/end views and pin configurations please see TAT, Relim Bookworks, Repco Auto Tech Encyclopedia, Auto Data, Automotive Service Solution

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3 a –Air conditioning pressure sensor supply voltage

Locate ACP under hood

Locate 5 volt supply wire (brown yellow)

And back-probe wire without disconnecting

connector

Turn Ignition switch ON, what do you observe

Turn Ignition OFF, how long does it take before 5

volt supply drops out!

Explain the significance of delay in ‘drop-out’!

What setting must you have to ‘see’ the

accompanied waveform to the right?

X-axis / time base setting = ………milli second / Division

Y-axis / voltage scale =…………………volts / Division

2 –Fuel ump current Draw

Whilst ignition switch in the OFF position, locate

fuel pump relay (under hood)

Identify terminals 3 and 5 - PLEASE – Be extra

cautious.

Insert 0.1 Ohm 5 watt ceramic resistor in-place of

fuel pump relay in terminals 3 and 5onto base of

fuse box assembly

Explain as to why the fuel pump is now ON

…………!

Connect Oscilloscope’s Red probe to terminal 3and

Grey probe onto terminal 5 (whilst resistor in place)

What setting must you have to ‘see’ the

accompanied waveform to the right?

Prepared for WIRE & GAS 2012 Training Convention ACTIVITIES Group A – Oscilloscope waveform types & interpretation Authors: Sam Nazarian & Jack Stepanian

All Rights Reserved Long Reef Garage PTY LTD All recorded measurements are believed to be true representation of and are based on unproblematic motor vehicle management. ALL rights are reserved to make changes without prior

notice. ALL conditions prescribed under the copyright act are reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical without prior expressed written notice, it is an offence – All intellectual materials are the property of the authors.

For Circuit diagrams, connector Location/end views and pin configurations please see TAT, Relim Bookworks, Repco Auto Tech Encyclopedia, Auto Data, Automotive Service Solution

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3 c –Air Conditioning and cooling fan relays removed

Locate FAN1, FAN2 Fan3 relays under hood

Start engine and whilst monitoring ACP signal

waveform observe operating voltage range

What setting must you have to ‘see’ the

accompanied waveform to the right?

Why does the signal oscillate

At what voltage does compressor clutch cut-out!

Refit relay FAN3 and observe change in waveform

Refit relay FAN2 and observe change in waveform

Refit relay FAN1 and observe change in waveform

Do cooling fans ever stop ‘working’! Why and at

what voltage! (turn ignition off)

3 b –Air Conditioning pressure sensor signal voltage

Locate ACP signal output wire (middle wire –

brown)

Back-probe

Start engine

Turn Air Conditioning ON

Observe waveform

What setting must you have to ‘see’ the

accompanied waveform to the right?

Does waveform change as A/C cuts in and out!

Please explain observed waveform

What happen to the waveform when ignition is

turned OFF!

Prepared for WIRE & GAS 2012 Training Convention ACTIVITIES Group A – Oscilloscope waveform types & interpretation Authors: Sam Nazarian & Jack Stepanian

All Rights Reserved Long Reef Garage PTY LTD All recorded measurements are believed to be true representation of and are based on unproblematic motor vehicle management. ALL rights are reserved to make changes without prior

notice. ALL conditions prescribed under the copyright act are reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical without prior expressed written notice, it is an offence – All intellectual materials are the property of the authors.

For Circuit diagrams, connector Location/end views and pin configurations please see TAT, Relim Bookworks, Repco Auto Tech Encyclopedia, Auto Data, Automotive Service Solution

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5 –Supply voltage – Battery post to post

Locate battery under hood & connect red and grey

probes to respective battery posts

Crank engine and allow to start, idle then turn

ignition OFF

Explain observed waveform

What setting must you have to ‘see’ the

accompanied waveform to the right?

X-axis / time base setting = ………milli second / Division

Y-axis / voltage scale =…………………volts / Division

What is meant by the term ‘AC coupling’ and what

effect will it have on captured waveform – please

explain

4 –Primary ignition pattern at idle

Identify connector A (orient ECM such that

connectors facing you – left blanked out connector

C and to the right connector A)

Identify and back-probe terminal A46

Whist engine at idle observe and explain 3 spikes!

What setting must you have to ‘see’ the

accompanied waveform to the right?

X-axis / time base setting = ………milli second / Division

Y-axis / voltage scale =…………………volts / Division

Hint: select top left ms/div and bottom left trigger Auto

Rev engine to 3,000 rpm, does waveform / spikes

alter!

Prepared for WIRE & GAS 2012 Training Convention ACTIVITIES Group A – Oscilloscope waveform types & interpretation Authors: Sam Nazarian & Jack Stepanian

All Rights Reserved Long Reef Garage PTY LTD All recorded measurements are believed to be true representation of and are based on unproblematic motor vehicle management. ALL rights are reserved to make changes without prior

notice. ALL conditions prescribed under the copyright act are reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical without prior expressed written notice, it is an offence – All intellectual materials are the property of the authors.

For Circuit diagrams, connector Location/end views and pin configurations please see TAT, Relim Bookworks, Repco Auto Tech Encyclopedia, Auto Data, Automotive Service Solution

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6 b –Throttle actuator motor control (at 2,500rpm)

Repeat above settings however whilst observing

waveform raise engine speed from idle (700rpm) to

slightly above 3,000rpm.

At what engine speed the pulsed waveform ceases to

exist! And what happens as you keep on increasing

the speed of the engine!

Does the pulse width change at all!

If so, please explain why!

What setting must you have to ‘see’ the

accompanied waveform to the right?

X-axis / time base setting = ………milli second / Division

Y-axis / voltage scale =…………………volts / Division

6 a –Throttle actuator motor control (at idle)

Locate throttle actuator motor (throttle body)

Identify colors of connector

Connect red oscilloscope probe to upper terminal

Connect grey oscilloscope probe to lower terminal

Start car and allow idle

What setting must you have to ‘see’ the

accompanied waveform to the right?

X-axis / time base setting = ………milli second / Division

Y-axis / voltage scale =…………………volts / Division

Turn ignition OFF, observe and explain waveform

when ignition is turned ON, engine crank, start then

idle

Prepared for WIRE & GAS 2012 Training Convention ACTIVITIES Group A – Oscilloscope waveform types & interpretation Authors: Sam Nazarian & Jack Stepanian

All Rights Reserved Long Reef Garage PTY LTD All recorded measurements are believed to be true representation of and are based on unproblematic motor vehicle management. ALL rights are reserved to make changes without prior

notice. ALL conditions prescribed under the copyright act are reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical without prior expressed written notice, it is an offence – All intellectual materials are the property of the authors.

For Circuit diagrams, connector Location/end views and pin configurations please see TAT, Relim Bookworks, Repco Auto Tech Encyclopedia, Auto Data, Automotive Service Solution

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8 –Manifold Absolute Pressure sensor (MAP)

Identify connector A (orient ECM such that

connectors facing you – left blanked out connector

C and to the right connector A)

Identify and back-probe terminal A38

Whist engine at idle snap throttle twice, observe and

explain waveform. What setting must you have to

‘see’ the accompanied waveform to the right?

X-axis / time base setting = ………milli second / Division

Y-axis / voltage scale =…………………volts / Division

Hint: explain the ‘hash’ (noise) on signal waveform and

how one may reduce it without whilst maintain the fidelity!

7 –Injector pattern

Locate injector under hood (most convenient /

exposed) and identify supply connecting terminal

Identify trigger terminal and measure waveform at

idle and note settings

X-axis / time base setting = ………milli second / Division

Y-axis / voltage scale =…………………volts / Division

Explain the significance of the ‘hump’ on the

trailing edge of the spike!

Increase speed of engine (slowly) does pulse width

change! Is it any different if ‘snapp-throttled’!

Hint: Move yellow diamond on trace –( middle of trace) to

stabilize waveform

Prepared for WIRE & GAS 2012 Training Convention ACTIVITIES Group A – Oscilloscope waveform types & interpretation Authors: Sam Nazarian & Jack Stepanian

All Rights Reserved Long Reef Garage PTY LTD All recorded measurements are believed to be true representation of and are based on unproblematic motor vehicle management. ALL rights are reserved to make changes without prior

notice. ALL conditions prescribed under the copyright act are reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical without prior expressed written notice, it is an offence – All intellectual materials are the property of the authors.

For Circuit diagrams, connector Location/end views and pin configurations please see TAT, Relim Bookworks, Repco Auto Tech Encyclopedia, Auto Data, Automotive Service Solution

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10 –Automatic transmission range switch (PRNDL)

Identify connector A (orient ECM such that

connectors facing you – left blanked out connector

C and to the right connector A)

Identify and back-probe terminal B41

Turn ignition ON and by moving selector ‘T’ bar

slowly select Park, Reverse, Neutral, Drive and

Low! (Active select!), observe and explain

waveform.

What setting must you have to ‘see’ the

accompanied waveform to the right?

X-axis / time base setting = ………milli second / Division

Y-axis / voltage scale =…………………volts / Division

9 –Crank Shaft Position Sensor (CKP)

Identify connector A (orient ECM such that

connectors facing you – left blanked out connector

C and to the right connector A)

Identify and back-probe terminal A41

Whist engine at idle slowly increase engine speed,

observe and explain waveform.

What setting must you have to ‘see’ the

accompanied waveform to the right?

X-axis / time base setting = ………milli second / Division

Y-axis / voltage scale =…………………volts / Division

Prepared for WIRE & GAS 2012 Training Convention ACTIVITIES Group A – Oscilloscope waveform types & interpretation Authors: Sam Nazarian & Jack Stepanian

All Rights Reserved Long Reef Garage PTY LTD All recorded measurements are believed to be true representation of and are based on unproblematic motor vehicle management. ALL rights are reserved to make changes without prior

notice. ALL conditions prescribed under the copyright act are reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical without prior expressed written notice, it is an offence – All intellectual materials are the property of the authors.

For Circuit diagrams, connector Location/end views and pin configurations please see TAT, Relim Bookworks, Repco Auto Tech Encyclopedia, Auto Data, Automotive Service Solution

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12 –Cam Shaft Sensor

Either

Identify connector A (orient ECM such that

connectors facing you – left blanked out connector

C and to the right connector A). Identify and back-

probe terminal A31 or A33

OR

Physically identify Cam shaft sensor on block and

back-probe signal side of the sensor

Whilst engine at idle, what setting must you have to

‘see’ the accompanied waveform to the right?

X-axis / time base setting = ………milli second / Division

Y-axis / voltage scale =…………………volts / Division

11 –Cylinder Head Temperature Sensor

Identify connector A (orient ECM such that

connectors facing you – left blanked out connector

C and to the right connector A)

Identify and back-probe terminal A45

Whist engine cold turn ignition ON, place 5,000

Ohm potentiometer from terminal A45 to earth

(engine block) and then slowly rotate to reduce and

increase resistance (in a rhythmic fashion)

What setting must you have to ‘see’ the

accompanied waveform to the right?

X-axis / time base setting = ………milli second / Division

Y-axis / voltage scale =…………………volts / Division

Prepared for WIRE & GAS 2012 Training Convention ACTIVITIES Group A – Oscilloscope waveform types & interpretation Authors: Sam Nazarian & Jack Stepanian

All Rights Reserved Long Reef Garage PTY LTD All recorded measurements are believed to be true representation of and are based on unproblematic motor vehicle management. ALL rights are reserved to make changes without prior

notice. ALL conditions prescribed under the copyright act are reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical without prior expressed written notice, it is an offence – All intellectual materials are the property of the authors.

For Circuit diagrams, connector Location/end views and pin configurations please see TAT, Relim Bookworks, Repco Auto Tech Encyclopedia, Auto Data, Automotive Service Solution

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Waveform of your own choice

Capture a waveform and note X and Y axis

Explain captured waveform - Ignition On, Crank,

Start, Run, Snap-throttle, back to idle then ignition

OFF (if applicable)

Thank You

13 –Cam Shaft Actuator

Either

Identify connector A (orient ECM such that

connectors facing you – left blanked out connector

C and to the right connector A). Identify and back-

probe terminal A5 or A6

OR

Physically identify Cam shaft sensor on block and

back-probe signal side of the sensor

Whilst ‘snap throttle, what setting must you have to

‘see’ the accompanied waveform to the right?

X-axis / time base setting = ………milli second / Division

Y-axis / voltage scale =…………………volts / Division

Prepared for WIRE & GAS 2012 Training Convention ACTIVITIES Group A – Oscilloscope waveform types & interpretation Authors: Sam Nazarian & Jack Stepanian

All Rights Reserved Long Reef Garage PTY LTD All recorded measurements are believed to be true representation of and are based on unproblematic motor vehicle management. ALL rights are reserved to make changes without prior

notice. ALL conditions prescribed under the copyright act are reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical without prior expressed written notice, it is an offence – All intellectual materials are the property of the authors.

For Circuit diagrams, connector Location/end views and pin configurations please see TAT, Relim Bookworks, Repco Auto Tech Encyclopedia, Auto Data, Automotive Service Solution

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Notes