Actron CP7677, Operating Instructions Manual

Page 1: ...ery Test 15 Engine Off Battery Current Draw 15 CP7677 Auto TroubleShooter OPERATING INSTRUCTIONS Cranking Voltage Battery Load Test 16 Voltage Drops 17 Charging System Voltage Test 18 Ignition System Testing 19 Ignition Coil Testing 19 Ignition System Wires 21 Hall Effect Sensors Switches 22 Magnetic Pick Up Coils 23 Reluctance Sensors 23 Ignition Coil Switching Action 24 Fuel System Testing 25 Te...

Page 2: ...age when the engine is running Always turn ignition key OFF when connecting or disconnecting electrical components unless otherwise instructed Always follow vehicle manufacturer s warnings cautions and service procedures CAUTION Some vehicles are equipped with safety air bags You must follow vehicle service manual cautions when working around the air bag components or wiring If the cautions are no...

Page 3: ...t reconnected in the wrong place or not at all Don t take shortcuts Inspect hoses and wiring which may be difficult to see due to location Inspect the air cleaner and ductwork for defects Check sensors and actuators for damage Inspect ignition wires for Damaged terminals Split or cracked spark plug boots Splits cuts or breaks in the ignition wires and insulation Inspect all vacuum hoses for Correc...

Page 4: ...the test prod If the crimp on the alligator clip becomes loose then remove the alligator clip from the test prod and re crimp using a pair of pliers Section 1 Multimeter Basic Functions Digital multimeters or DMMs have many special features and functions This section defines these features and functions and explains how to use these functions to make various measurements 10 8 7 1 2 3 5 12 4 9 6 ...

Page 5: ... 10 TACH This function is used for measuring engine speed RPM 11 ON OFF Press to turn power ON Press again to turn power OFF 12 DISPLAY Used to display all measurements and multimeter information Low Battery If this symbol appears in the lower left corner of the display then replace the inter nal 9V battery See Fuse and Battery re placement on page 7 Overrange Indication If 1 or 1 appears on the l...

Page 6: ...is still showing that it is overranging then the value being measured is too large for the mul timeter to measure How do I know what Range the multi meter should be set to The multimeter should be set in the lowest possible range without overranging EXAMPLE Measuring an unknown re sistance Let s assume the multimeter is con nected to an engine coolant sensor with unknown resistance See Fig 3 Fig 2...

Page 7: ...curacy of the measurement by ei ther increasing or decreasing the number of digits after the decimal point Battery and Fuse Replacement Important A 9 Volt battery must be in stalled before using the digital multim eter see procedure below for installa tion Battery Replacement 1 Turn multimeter OFF 2 Remove test leads from multimeter 3 Remove screw from battery cover 4 Remove battery cover 5 Instal...

Page 8: ... then arbitrarily connect the RED test lead to one side and the BLACK to the other The multimeter automatically senses polarity and will display a minus sign when nega tive polarity is measured If you switch the RED and BLACK test leads positive polarity will now be indicated on the display Measuring negative voltages causes no harm to the multimeter 5 Turn multimeter rotary switch to desired volt...

Page 9: ...electrically open cir cuit where you want to measure current This is done by Disconnecting wiring harness Disconnecting wire from screw on type terminal Unsolder lead from component if Red Black Unknown Resistance Measuring Resistance Resistance is measured in electrical units called ohms Ω The digital multi meter can measure resistance from 0 1Ω to 20MΩ or 20 000 000 ohms Infinite resistance is s...

Page 10: ...uit is closed or shorted so you don t have to look at the display Continuity checks are usually done when checking for blown fuses switch opera tion and open or shorted wires To measure Continuity see Fig 12 Fig 12 Black Red Fig 10 Black Red Electrical Device DC Voltage Source Fig 11 Black Red Electrical Device DC Voltage Source 1 Insert BLACK test lead into COM test lead jack 2 Insert RED test le...

Page 11: ...nt would flow Therefore in order to test a diode you must check it in both directions i e anode to cathode and cathode to an ode Diodes are typically found in alter nators on automobiles Performing Diode Test see Fig 13 Typical Ignition Coil Ground Black Red Fig 14 Anode Cathode Black Red 1 Insert BLACK test lead into COM test lead jack 2 Insert RED test lead into test lead jack 3 Connect RED test...

Page 12: ...adjust able Another application for dwell is in testing the mixture control solenoid on GM feedback carburetors To measure Dwell see Fig 15 Ground Black Red Fig 15 Typical Ignition Coil 1 Insert BLACK test lead into COM test lead jack 2 Insert RED test lead into test lead jack 3 Connect RED test lead to DWELL signal wire If measuring DWELL on breaker point ignition systems connect RED test lead to...

Page 13: ...pe and rating Testing Switches This test checks to see if a switch Opens and Closes properly To test Switches see Fig 17 Fig 17 Red Typical Push Button Switch 1 Insert BLACK test lead into COM test lead jack 2 Insert RED test lead into test lead jack 3 Turn multimeter rotary switch to function 4 Touch RED and BLACK test leads together to test continuity Listen for tone to verify proper op eration ...

Page 14: ...ange on every ohms range indicating an open cir cuit NOTE Some relays and solenoids have a diode placed across the coil To test this diode see Testing Di odes on page 11 1 Insert BLACK test lead into COM test lead jack 2 Insert RED test lead into test lead jack 3 Turn multimeter rotary switch to 200Ω function Most solenoids and relay coil resis tances are less than 200Ω If meter overranges turn mu...

Page 15: ...nto test lead jack 5 Disconnect positive battery cable 6 Connect RED test lead to positive terminal of battery 7 Connect BLACK test lead to nega tive terminal of battery 8 Turn multimeter rotary switch to 20V DC range 9 View reading on display 10 Test Results Compare display reading in Step 9 with the following chart Percent Voltage Battery is Charged 12 60V or greater 100 12 45V 75 12 30V 50 12 1...

Page 16: ...king Voltage Battery Load Test This test checks the battery to see if it is delivering enough voltage to the starter motor under cranking conditions Test Procedure see Fig 21 1 Disable ignition system so vehicle won t start Disconnect the primary of the igni tion coil or the distributor pick up coil or the cam crank sensor to disable the ignition system Refer to vehicle service manual for disablin...

Page 17: ...ricts the amount of current that reaches the starter motor resulting in low battery load voltage and a slow cranking engine at starting Test Procedure see Fig 22 1 Disable ignition system so vehicle won t start Disconnect the primary of the igni tion coil or the distributor pick up coil or the cam crank sensor to disable the ignition system Refer to vehicle service manual for disabling proce dure ...

Page 18: ...ual then check for a loose alternator belt defective regulator or alterna tor poor connections or open al ternator field current Refer to vehicle service manual for further diagnosis This test checks the charging system to see if it charges the battery and pro vides power to the rest of the vehicles electrical systems lights fan radio etc Test Procedure see Fig 23 Fig 23 Red Black 1 Insert BLACK t...

Page 19: ...ad into COM test lead jack see Fig 24 7 Connect test leads Connect RED test lead to primary ignition coil positive terminal Connect BLACK test lead to primary ignition coil negative terminal Refer to vehicle service manual for location of primary ignition coil ter minals 8 View reading on display Subtract test lead resistance found in Step 6 from above reading 9 If vehicle is DIS repeat Steps 7 an...

Page 20: ...y ignition coils is 6 0 30 0KΩ Refer to vehicle service manual for your vehicles resistance range 16 Repeat test procedure for a HOT ignition coil NOTE It is a good idea to test ignition coils when they are both hot and cold because the resistance of the coil could change with tempera ture This will also help in diagnosing intermittent ignition system prob lems 17 Test Results Overall Good Ignitio...

Page 21: ...e service manual for procedure NOTE Some spark plug wires have sheet metal jackets with the follow ing symbol This type of plug wire contains an air gap resistor and can only be checked with an oscilloscope 2 Insert BLACK test lead into COM test lead jack see Fig 26 3 Insert RED test lead into test lead jack 4 Connect RED test lead to one end of ignition wire and BLACK test lead to other end 5 Tur...

Page 22: ...LACK test lead into COM test lead jack 4 Insert RED test lead into test lead jack 5 Connect RED test lead to sensor SIGNAL pin 6 Connect BLACK test lead to 9V battery negative pin 7 Turn multimeter rotary switch to function Multimeter should sound a tone 8 Slide a flat blade of iron or mag netic steel between sensor and magnet Use a scrap of sheet metal knife blade steel ruler etc Multimeter tone ...

Page 23: ... Insert BLACK test lead into COM test lead jack 2 Insert RED test lead into test lead jack Reluctor Ring Magnet 3 Connect RED test lead to either sensor pin 4 Connect BLACK test lead to re maining sensor pin 5 Turn multimeter rotary switch to 2KΩ range 6 View reading on display while flex ing sensor wires in several places Typical resistance range is 150 1000Ω Refer to vehicle service manual for y...

Page 24: ...mputer refer to vehicle service manual for location of this wire For all vehicles with distributors connect RED test lead to negative side of primary ignition coil refer to vehicle service manual for loca tion of ignition coil 4 Connect BLACK test lead to a good vehicle ground 5 Turn multimeter rotary switch to correct CYLINDER selec tion in RPM 6 View reading on display while engine is cranking T...

Page 25: ...intain an air fuel ratio of 14 7 to 1 in order to reduce emissions This test checks to see if the solenoid dwell is varying Test Description This test is rather long and detailed Refer to vehicle service manual for the com plete test procedure Some important test procedure highlights you need to pay close attention to are listed below 1 Make sure engine is at operating temperature and running duri...

Page 26: ...nnect RED and BLACK test leads across fuel injector pins Make sure you connect test leads across fuel injector and not the wir ing harness 6 Turn multimeter rotary switch to desired OHM range If the approximate resistance is unknown start at the largest OHM range and decrease to the appropriate range as required see Setting the Range on page 6 7 View reading on display Note range setting for cor r...

Page 27: ...voltage low resistance indicates a rich exhaust not enough oxygen The com puter uses this voltage to adjust the air fuel ratio The two types of O2 Sensors commonly in use are Zirconia and Tita nia Refer to illustration for appearance differences of the two sensor types Test Procedure see Fig 31 1 If engine is HOT let it COOL down before proceeding 2 Remove Oxygen Sensor from ve hicle 3 Insert BLAC...

Page 28: ... surround sensor tip with flame to deplete sensor of oxygen Rich Condition Multimeter display should read 0 6V or greater for Zirconia Type Sensors an Ohmic Resistance value for Titania Type Sensors Reading will vary with flame temperature While still applying heat to sensor move flame such that oxygen can reach sensor tip Lean Condition Multimeter display should read 0 4V or less for Zirconia Typ...

Page 29: ...at up sensor If testing Intake Air Temperature Sen sor To heat up sensor dip sensor tip into boiling water or Heat tip with a lighter if sensor tip is metal or a hair dryer if sensor tip is plastic View and record smallest reading on display as sensor is heated You may need to decrease the range to get a more accurate read ing For all other temperature sensors Start engine and let idle until upper...

Page 30: ...ging adjust the range accordingly See Set ting the Range on page 6 Typical Toyota Throttle Position Sensor Red Black POWER GROUND SIGNAL IDLE SWITCH To test these switches follow the Testing Switches test procedure on page 13 When you are told to operate switch then move throttle linkage Vane Air Flow Sensor Slowly open vane door from closed to open by pushing on it with a pencil or similar object...

Page 31: ...on the type of MAP sensor the signal may be a dc voltage or a frequency GM Chrysler Honda and Toyota use a dc voltage MAP sensor while Ford uses a frequency type For other manufactur ers refer to vehicle service manual for type of MAP sensor used Test Procedure see Fig 34 1 Insert BLACK test lead into COM test lead jack 2 Insert RED test lead into test lead jack 3 Disconnect wiring harnc Û and vac...

Page 32: ...anu facturers specifications at 0 in of vacuum Sensor output voltage or frequency RPM decrease with increasing vacuum Bad Sensor Sensor output voltage or frequency RPM are not within manufactur ers specifications at 0 in of vacuum Sensor output voltage or frequency RPM do not change with increas ing vacuum Mass Air Flow MAF Sensors This sensor sends a signal to the com puter indicating the amount ...

Page 33: ...r Display reading should be approxi mately 1V or less depending on MAF sensor manufacturer Low Frequency Type Sensor Display reading should be approxi mately 330RPM 5 for GM Low Frequency MAF sensors For other Low Frequency type MAF sensors refer to vehicle service manualforMAFsensorspecifications It is O K if last two display digits change slightly while Key is ON Remember to multiply display rea...

Page 34: ...750V Accuracy 1 0 rdg 4 dgts DC Current Range 200mA Accuracy 0 8 rdg 5 dgts Range 10A Accuracy 1 2 rdg 5 dgts Resistance Range 200Ω 2KΩ 20KΩ 200KΩ 2MΩ Accuracy 0 8 rdg 5 dgts Range 20MΩ Accuracy 1 5 rdg 5 dgts Dwell Range 4CYL 6CYL 8CYL Accuracy 3 0 rdg 5 dgts RPM Range 4CYL 6CYL 8CYL Accuracy 3 0 rdg 5 dgts Audible Continuity Buzzer sounds at approximately less than 30 50 Ohms ...