Automotive articles

Diagnose

This page lists miscellaneous automotive articles and diagnostics articles about solving real life car problems. What seems to be a complex problem at first, can be an easy fix after diagnosing the problem with an automotive lab scope with differential inputs. All articles show the importance of measuring with an automotive lab scope with differential inputs to diagnose the problem to find the real source.

Each diagnostics article states the type of vehicle and motor management system, a detailed description of the problem and measurements that are performed to find to the cause of the problem. At the end of each article, the cause and solution of the problem are shown together with a measurement showing the repair was effective.

Miscellaneous

Miscellaneous articles about automotive related subjects.

Diagnostics

The diagnostics articles listed below show how real life problems in various cars were solved using an automotive oscilloscope.

  • Citroën Berlingo with headache
    Citroën Berlingo (2011)1.6 VTi 120 (5FS)Bosch MEV 17.4.2
    Citroën Berlingo with headache

    After disassembling and reassembling the cylinder head of a 2011 Citroën Berlingo, the engine would not run anymore, producing camshaft related errors. Using an automotive diagnostic oscilloscope, the cause of the problem was found.

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  • Exhausted Mercedes E-class
    Mercedes E-class (2003)3.2L Bosch CP3
    Exhausted Mercedes E-class

    A Mercedes E-class was hard to start, flattened the battery and left the owner stranded. The first garage is was sent to concluded that the immobilizer ECU had forgotten the key codes. The vehicle was then sent to a garage with AECS technical support and using an automotive diagnostic oscilloscope and RFS400 return flow sensor the found the real cause of the problem.

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  • Kia Carens with mixture issue
    Kia Carens 1.6 L (A6)Bosch Motronic 7.9.1
    Kia Carens with mixture issue

    A Kia Carens with 1.6 liter engine keeps generating an oxygen sensor related code that the fuel mixture was too rich. Resetting the error and driving the car would set the error code again. Several components were replaced, even the Electronic Control Module (ECM), but the error kept coming back. Diagnosing using a automotive lab scope revealed the cause of the problem.

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  • Citroën Xantia refuses to run
    Citroën Xantia (1999)2.0 L (XU10 J2C)Magneti Marelli 8P
    Citroën Xantia refuses to run

    A 1999 Citroën Xantia had a new starter motor fitted, after which it would not run anymore. While cranking it would fire briefly and then die. The car’s battery had been disconnected for the starter motor job. A crankshaft sensor code was logged and thus the crankshaft sensor was replaced, regardless of the good signal. Later the ECM was replaced all with no positive results. The question was if the immobilizer could have reset itself by disconnecting the battery. Proper measuring revealed what the real problem was.

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  • Ford Fiesta stutters
    Ford Fiesta 1.3 L (J6B)FORD CFI EEC-IV
    Ford Fiesta stutters

    When trouble shooting intermittent problems, a good automotive oscilloscope is indispensable. A Ford Fiesta with J6B engine was suffering occasional stuttering. The shop it was brought to did not have an oscilloscope, so they could not easily locate the source of the problem. They did replace some components, but the problem remained. Using an automotive diagnostic oscilloscope, the problem was soon found.

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  • Hesitant Renault Megane
    Renault Megane (1998)1.6 L (K7M)Siemens Fenix 5
    Hesitant Renault Megane

    Intermittent problems in cars can give garages a hard time, especially when their only diagnosis device is a fault code scanner and no codes are stored in the car. A garage deals with a 1998 Renault Megane 1.6 L with K7M engine with a dual fuel system, both petrol and LPG. Every now and then, the engine hesitates, both on petrol and on LPG. The garage performs some measurements and replaces the ECM, to no avail. Using an automotive diagnostic oscilloscope the search was continued and the culprit was found.

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  • Ford Mondeo with fuel pump issue
    Ford Mondeo 2.0 L TDdi (D6BA)EEC V
    Ford Mondeo with fuel pump issue

    In modern cars with sophisticated and complex components, trouble shooting requires powerful tools. A Ford Mondeo 2.0 TDdi would no longer run. Fearing that wrong fuel was tanked, the tank was emptied and the fuel system cleaned. The proper fuel was added but the engine would still not start. Since wrong fuel was used, damage to the fuel pump was suspected. The pump was replaced, the engine replaced and the pump replaced once more, to no avail. Diagnosing using an automotive lab scope showed that a seemingly innocent component caused the problem.

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  • Troublesome Volvo XC70
    Volvo XC70 (2001)2.4L (B5244T3)Motronic-ME7
    Troublesome Volvo XC70

    A Volvo XC70 had serious engine related drivability problems. The engine lacked power, would hold back and even stall. Error codes indicated problems in two different areas. Replacing components did not improve things. Proper measuring with an automotive diagnostic oscilloscope revealed two independent problems. Fixing these solved all problems.

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  • Honda Jazz holds back and stalls
    Honda Jazz (2006)1.4 L (L13A i-DSI)Honda PGM-Fi
    Honda Jazz holds back and stalls

    A 2006 Honda Jazz with L13A i-DSI engine occasionally holds back and sometimes even stops. No error codes were stored in the car. Several components have been replaced or swapped with an other car. A lot was driven in the car with a scanner hooked up to monitor the "live data" to find an anomaly in sensor or actuator data. Nothing showed up. Only after diagnosing with a good automotive diagnostic oscilloscope, the cause of the problems was revealed.

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  • VW Golf 4 accelerates with loud explosions
    Volkswagen Golf 4 GTI (1999)1.8 L 20v Turbo (AGU)Motronic 3.8.3
    VW Golf 4 accelerates with loud explosions

    A Golf 4 turbo GTI was having serious problems with accelerating. Accelerating from 0 to 80 km per hour would take approximately 16 seconds, which is far too long for this car. Apart from the lack of power, the engine would hold back every half second and produce a lot of explosions in the exhaust. Based on an assumption, measuring with an automotive oscilloscope was started, but it lead to no solution. When the assumption was ignored and measuring was started at the basics, the cause was found in a different area than initially was thought.

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  • Opel Agila with electrical problems
    Opel Agila (2006)1.2 L (Z 12 XEP)Bosch Motronic ME 7.6.1
    Opel Agila with electrical problems

    An Opel Agila runs bad and generates lots of throttle related error codes. The garage replaces the throttle body, throttle position sensors, the ECM and even a part of the wiring harness, to no avail. When measuring the vital signals with an automotive oscilloscope, the cause of the problems is revealed.

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  • Saab 9-5 with intermittent hiccups
    Saab 9-5 (1999)2.0 L (B205E)Trionic T7
    Saab 9-5 with intermittent hiccups

    The engine of a 1999 Saab 9-5 intermittently shows a "hiccup" but then continues to run properly. Over time, the problem became worse and and at some point, the car would not start for 20 minutes. The owner consulted a garage that concluded that the special Direct Ignition cassette needed replacement. Unfortunately that did not solve the problem. Time to start measuring properly, using an automotive diagnostic oscilloscope.

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  • Renault Kangoo bad start
    Renault Kangoo (1998)1.4 (E7J 780)Siemens Fenix 5
    Renault Kangoo bad start

    A Renault Kangoo is suffering a bad start: it starts but stalls within 2 seconds. Several garages replace several parts but none can fix the problem. All signals appear OK, but are they? Thorough measuring with an automotive oscilloscope and analyzing the signals reveal the surprising culprit.

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  • Peugeot 205 holding back
    Peugeot 205 (1994)1.1 (HDZ)G6
    Peugeot 205 holding back

    When a Peugeot 205 is performing a strong accelleration, it starts holding back. When it is cruising, nothing is wrong. Several components were replaced, without result. The automotive oscilloscope was used to measure various signals, which led to finding a simple mechanical problem.

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  • Ford F150 with defective ignition coil
    Ford F150 (1998)5.4L V8 EEC V
    Ford F150 with defective ignition coil

    A Ford F150 has an ignition coil for each cylinder and one of them is defective. It is replaced by a new one, but that one breaks down within half an hour. It is replaced again, with the same result. Measuring with an automotive oscilloscope and a current clamp reveal that the ignition control module is defective.

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  • Toyota MR2 bad injector
    Toyota MR2 (2000)1.8L 16V VVT-i (1ZZ-FE)TCCS
    Toyota MR2 bad injector

    A Toyota MR2 is having problems after an engine replacement, fault code P0304 Cylinder #4 misfire detected occurs. The garage swaps several components but does not manage to fix the problem. Measurements with an automotive oscilloscope are required to find out that the fault code is somewhat misleading and the problem is not with cylinder #4

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  • Jeep Cherokee cranking, no start
    Jeep Cherokee (2002)2.5L CRD (R 425)
    Jeep Cherokee cranking, no start

    A Jeep Cherokee refused to start properly, only after long cranking it would eventually start. The dealer concluded that the engine was worn and needed to be replaced. Measuring with an automotive diagnostic oscilloscope and analyzing the signals showed that just a single sensor needed replacing.

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  • Fiat Stilo ECM defective or timing problem?
    Fiat Stilo
    Fiat Stilo ECM defective or timing problem?

    A Fiat Stilo would not start properly, only in 50% of the attempts it would run. Several fault codes were read, but none of them seemed related. An automotive oscilloscope was used to measure the vital signals, which showed a serious timing problem. Was it caused by a defective ECM or was there something else wrong?

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  • Engine stall on Voyager
    Chrysler Voyager 2.5L Bosch
    Engine stall on Voyager

    The engine of a Chrysler Voyager would occasionally stall, only once or twice a day, when running idle. After many attempts, the automotive oscilloscope could capture the vital signals when the engine stalled. Analysis of the signals indicated a defective HALL sensor.

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  • Audi A8 will not start
    Audi A8 (2000)4.2L V8 (BHF)Bosch Motronic ME 7.1
    Audi A8 will not start

    An Audi A8 refuses to start right after it has been driven. Only after letting it cool down, it will start again. The dealer was unable to fix this. After measuring various signals with an automotive oscilloscope, the problem could be traced back to a malfunctioning coolant temperature sensor.

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  • KIA Carnival Anti-lock Brake System Problem
    Kia Carnival (2000)2.5L V6 (KV6)Siemens K62
    KIA Carnival Anti-lock Brake System Problem

    The ABS warning light of a Kia Carnival would always light up when the speed exceeds 130 km per hour. The ABS wheel sensor was replaced twice, without solving the problem. Only by measuring with an automotive oscilloscope it became clear that a mechanical problem was causing the light to go on.

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  • VW Golf running roughly
    Volkswagen Golf GTI (1995)2.0L (ABF)Digifant 3.2
    VW Golf running roughly

    A Volkswagen Golf GTI runs fine for several kilometers but than suddenly starts running rough. The garage already replaced the ECM and several sensors, with no result. Measuring with an automotive diagnostic oscilloscope revealed a bad power supply for the ECM, caused by a defective relay.

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