PMM JUNE 2016 11

VEHICLETROUBLESHOOTER

DIAGNOSTIC TECHNIQUES

In this month’s issue we’re going tointroduce you to the added benefit ofvehicle diagnosis, using the built-inmulti-meter or oscilloscope functions

included in the KTS Vehicle CommunicationInterface (VCI), in conjunction with theserial diagnostic capabilities of the BoschESI 2.0 program.

Many technicians consider a graphingmulti-meter or oscilloscope an extrainvestment, along with all of the otherequipment required to effectively work onmodern cars today. The good news is that ifyou own a Bosch KTS 540, then it alreadyhas a single channel multi-meter included andour flagship tool – the KTS 570 – features atwo channel multi-meter or oscilloscopewhich is all ready for you to use (see Fig 1).The kit contains high quality colour-codedtest cables and probes, which use standard4mm ‘banana’ type connectors.

As we all know, often a DiagnosticTrouble Code (DTC) will only give a guide tothe general area of a system that is suspectedto be faulty or out of range. Once a DTC isread from the error memory of a control unit,a good fault finding process is required to testthe suspected component and its associatedelectrical circuit. In Bosch ESI 2.0, there aremany Service Information System (SIS)

repair instructions linked toan error memory codethat will suggest adirect measurementneeds to be made ofthe voltage supply,earth path, orsignal/command wire or componentresistance in the system (see Fig 2).

These values can be tested using theBosch KTS multi-meter or oscilloscope,along with ‘guided’ fault finding instructionsand technical data through ESI 2.0. This willgive you confidence in your results andshould certainly lead to an improved firsttime fix rate of your customers’ vehicles.

For this article, we’ll concentrate on themulti-meter and scope functions of the KTS570. Please remember that if you have a KTS540, there is no scope capability built into theVCI. For technicians that use a separateoscilloscope – such as the Bosch FSA 500 orFSA 720/740 series – then the KTS 540 isperfectly suitable for multi-meter use.

The KTS multi-meter functionsWe’ll first take a look at the Bosch KTSmulti-meter functions that can be usedalongside the ESI 2.0 vehicle diagnosticprogram. When the multi-meter is accessed

via the main menu (see Fig 3) a new windowwill appear on-screen with the multi-meterdisplay and measurement selection options.Now you can overlay the multi-meter resultsscreen over ESI 2.0 and see the serialdiagnostic data and direct measurements sideby side (see Fig 4).

The test results will be wirelesslydisplayed on your PC screen, with themeasurements taken by the probes attached tothe KTS VCI which is connected to thevehicle (see Fig 5). The readings can beshown in a numerical form, with a useful bargraph, or in a graphing trace format, with upto a minute across the screen. This gives theuser more convenience, depending on themeasurements being taken. Another greatfeature is that, just like the actual value time

This regular series of technical articles from Bosch focuses on how to get the best out

of its ESI[tronic] 2.0 software, which is used in conjunction with the KTS range of

diagnostic tools for vehicle fault diagnosis and service function procedures.

ROBERT BOSCH

KTS DIAGNOSTICS MADE ‘ESI’PART 8: UNDERSTANDING THE BUILT-IN MULTIMETER AND OSCILLOSCOPE

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12 JUNE 2016 PMM

profile display in ESI 2.0, the multi-metergraph can be paused, reviewed, saved andprinted (if necessary) for reference (see Fig6), showing battery voltage and current uponstarting the engine.

For voltage and current readings, we havethe choice of DC, AC or EFF (root meansquare) settings on both channels andresistance measuring up to 1 MΩ on channel1. You can connect a Bosch amps clamp withadapter for non-intrusive currentmeasurements to be displayed on screen. Areally useful additional feature of the KTSmulti-meter is the circuit break and shortcircuit function, which you can configure toemit an audible warning signal when youconduct a wiggle test on the suspect harnessto help you find wiring faults along a loom.

The KTS oscilloscopeNow we’ll look at our Bosch KTS 570 twochannel oscilloscope functions that can beused for even greater in-depth testing ofelectrical systems and components. The

beauty of using an oscilloscope is that itopens up a whole new dimension of systemdiagnosis by presenting to the user anaccurate graphical representation of voltageover time. This means you can see in detailwhat is actually happening in an electricalcircuit in real time. Fig 7 shows a PD injectorand crankshaft sensor signal.

Opened from the main menu, theoscilloscope screen can be viewed alongsidethe ESI 2.0 program and offers manycustomisable settings that enable you toeffectively capture and display the test resultsyou need. Trigger points can be set to be surethat signal recording starts where you want it toand waveform display options can be used toget the best results. There are too many optionsto describe them all here, but if you hoveryour cursor over any icon or soft key a ‘tooltip’ pops up with a description (see Fig 8).

The time base for both channels can be setbetween 50 micro seconds and 1 secondacross the screen. The safe continuous inputvoltage to the VCI is a maximum of 60V and

the scale of measurement in voltage candisplay from 100mV (10mV/division) up to200V (20V/div) up the screen. In the currentmeasurement, the amps scale can be selectedbetween 30A and 1,000A. If you pause thescope recording the buffer memory holds theprevious 25 screen captures, which can bescrolled through and reviewed. This isessential if you’re searching for anintermittent fault.

If only a single channel measurement isrequired then the blue and yellow cables canbe used for potential free testing when theblack earth cable is connected to channel two.This set-up can be particularly useful fortesting both signal wires of an inductivespeed sensor, for example.

When a signal is being collected, the ESI2.0 oscilloscope software automatically startsto calculate the specific signal on/off timesand frequency of the waveform, if it is arepeated signal such as a Pulse WidthModulated (PWM) duty cycle. This is reallyuseful if you’re checking the command signalto a component, such as a radiator fan controlmodule (as shown in Fig 9).

Another great feature of the scope is theability to choose the channel option for signalacquisition via the coloured test cablesconnected to the channel inputs of the VCI.Additionally, you can switch to the ‘PIN’input option, where the signal will be taken

VEHICLETROUBLESHOOTERDIAGNOSTIC TECHNIQUES

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from the communication pins of the 16 pinOBD socket that will already be connected tothe car. The earth pins 4 and 5 and powersupply pin 16 are not available to scope thisway but any of the other pins are (dependingon the vehicle configuration). For example, asingle wire ‘K’ line on pin 7 or a CAN Bussignal on the traditional pins of 3 & 11 or 6

& 14 could be ‘internally’ tested (as seen inFig 10). This can be a very quick and easyway to investigate if any control unitcommunication problems occur.

What are you waiting for?If you use a Bosch KTS 570 and haven’t triedoscilloscope testing, then we highlyrecommend that you give it go. This article isintended as a brief overview of the multi-

meter and scope capabilities within BoschKTS as, in reality, we could write a wholebook on the subject!

The Bosch Automotive training course‘WTE1 operation of Bosch KTS’ covers anintroduction to the in-built multi-meter andscope functions and is a great way to getsome experience under your belt. For thoselooking to step things up a level, the Bosch‘VSTD9 Oscilloscope Operation and SignalTest Methods’ training course goes intogreater detail of oscilloscope testing andwaveform analysis.

Until next time, happy scoping readers!

To request further details about the range of

KTS diagnostic tools from Bosch circle 080

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