 printable version
Test signals to ECM connector
Contacts connector ECM (by wiring)  Below are the test conditions and suitable signals taken from the connector pin ECM. | Contact | Device | Conditions | Signal | | 1 | Grounding ECM | The engine operates at the speed of X / X | Grounding of the motor | | 2 | Heater postkataliticheskogo lambda probe | Warm up the engine operates at the speed of not more than 3800 rev / min | 0 ÷ 1 | | The engine is switched off (ignition on) or the engine runs at speeds above 3800 r / min | 11 ÷ 14 | | 3 | Power switch activator throttle | Ignition ON | 11 ÷ 14 | | 4 (5) | Activator throttle closed (open) position | Engine off, ignition on, the gas pedal is released, Manual transmission on the 1st transmission (AT mode "D") |   | | 13 | CKP sensor | The engine is warm and running at the speed of X / X |  | | The engine is running at 2000 rev / min |  | | 14 | CKP sensor | The engine is warm and running at the speed of X / X |  | | The engine is running at 2000 rev / min |  | | 15 | Knock sensor | The engine operates at the speed of X / X | Approximately 2.5 | | 16 | Postkatalitichesky lambda probe | The engine is warm and running at speeds no higher than 3600 rev / min | 0 ÷ 1 | | 19 | E / m purge control valve absorber | The engine operates at the speed of X / X |  | | The engine is running at 2000 rev / min |  | | 22, 23, 41, 42 | Injector ?��?�� 3,1,4,2, respectively | The engine is warm and running at the speed of X / X |  | | The engine is warm and running at 2000 rev / min |  | | 24 | Heater dokataliticheskogo lambda probe | The engine is warm and running at speeds no higher than 3600 rev / min |  | | The engine is warm and running at speeds up to 3600 rev / min | 11 ÷ 14 | | 29 // 30 | Ground sensor CMP // CKP | The engine operates at the speed of X / X | About 0 | | 34 | IAT sensor | The engine works | 0 ÷ 4.8 V, depending on the temperature | | 35 | Dokatalitichesky lambda probe | The engine is warm and running at 2000 rev / min | 0 ÷ 1 (periodic change) | | 45 | Sensor supply | Ignition ON | Approximately 5 | | 46 // 47 | Power refrigerant pressure sensor K / V // TPS sensor | Ignition ON | Approximately 5 | | 49 | The sensor TPS 1 | Engine off, ignition on, the gas pedal is released // depressed, Manual transmission on the 1st transmission (AT mode "D") | More than 0.36 // At least 4.75 | | 51 | MAP Sensor | The engine is warm and running at the speed of X / X | Approximately 1.5 | | The engine is warm and running at 2000 rev / min | Approximately 1.2 | | 54 // 56 // 57 | Grounding knock sensor // MAP // refrigerant pressure sensor K / | The engine is warm and running at the speed of X / X | About 0 | | 60, 61, 79, 80 | The signal plug in the cylinder ?��?�� 3,1,4,2, respectively | The engine is warm and running at the speed of X / X |  | | The engine is warm and running at 2000 rev / min |  | | 62 | E / m-phase control valve inlet valves | The engine is warm and running at the speed of X / X |  | | At increase in turns warm engine up to 2000 rev / min |  | | 66 | Ground sensors TPS | The engine is warm and running at the speed of X / X | About 0 | | 68 | TPS sensor 2 | Engine off, ignition on, the gas pedal is released // depressed, Manual transmission on the 1st transmission (AT mode "D") | Less than 4.75 // 0.36 more in | | 69 | Coolant pressure sensor | The engine is warm and running; K / B and the heater fan are included | 1 ÷ 4 | | 72 | ECT sensor | The engine works | 0 ÷ 4.8 V, depending on the temperature | | 73/74/82/83 | Ground sensor ECT / lambda probe / sensor APP1 / APP2 | The engine is warm and running at the speed of X / X | About 0 | | 85 | Diagnostic connector | Ignition on, the scanner disconnected | 11 ÷ 14 | | 86 | CAN Bus | Ignition ON | 1.0 ÷ 2.5 in | | 90/91 | Sensor supply APP1 / APP2 | Ignition ON | Approximately 5 | | 92 | The sensor output TPS (model AT) | Engine off, ignition on, AT mode "D", the gas pedal is released // depressed | Approximately 0.5 V // 4.2 | | 94 | CAN Bus | Ignition ON | 2.5 ÷ 4.0 in | | 98 | APP sensor 2 | Engine off, ignition on, the gas pedal is released // depressed | 0.3 ÷ 0.6 The // 1.95 ÷ 2.4 in | | 101 | D / stoplights | // Release the brake pedal depressed | 0 // 11 ÷ 14 | | 102 | Sensor PNP | Ignition ON, AT in position "P" or "N" (Manual transmission in neutral) | About 0 | | Ignition ON, transmission in other states | 11 ÷ 14 | | 103 | The output of the tachometer (AT model) | The engine is warm and running at the speed of X / X |  | | The engine is running at 2000 rev / min |  | | 104 | Relay Throttle | Ignition off // Included | 11 ÷ 14 V // 0 ÷ 1 | | 106 | APP sensor 1 | Engine off, ignition on, the gas pedal is released // depressed | 0.6 ÷ 0.9 The // 3.9 ÷ 4.7 in | | 109 | Ignition Switch | Ignition off // Included | 0 // 11 ÷ 14 | | 111 | Relay ECM | During // 5 seconds after switching off the engine (ignition off) | 0 ÷ 1 ÷ 11 // 14 | | 113 | Fuel pump relay | During // 1 second after switching on the ignition | 0 ÷ 1 ÷ 11 // 14 | | 115, 116 | Grounding ECM | The engine operates at the speed of X / X | Grounding of the motor | | 119, 120 | Power ECM | Ignition ON | 11 ÷ 14 | | 121 | Backup power ECM | Ignition off | 11 ÷ 14 |
 | The waveform displayed on the diagnostic tool Nissan, given above. Under each waveform contains the scale interval. |
DMMs are ideal for testing are in the static state of electrical circuits, as well as for fixing slow changes monitored parameters. During the same dynamic checks performed on the engine is running, as well as in identifying the causes of recurrent failures totally indispensable tool becomes an oscilloscope. Some oscilloscopes allow you to save the waveform in the embedded memory module and then print the results or copy them to digital media is already in a hospital. The oscilloscope allows to observe periodic signals and measure the characteristics of rectangular pulses, as well as levels of slowly varying voltages. The oscilloscope can be used to: - Identifying failures unstable nature;
- Check the results produced patches;
- Monitoring the activity of the lambda probe;
- Analysis produced by the lambda probe signal parameters deviate from the norm which is the clear evidence of infringement of serviceability of functioning of a control system as a whole - on the other hand, the correct form issued by the lambda probe pulses can serve as a reliable guarantee of non-infringement in the control system.
Reliability and ease of use of modern oscilloscopes do not require special operator expertise. Interpretation of the information obtained can be easily made by elementary visual comparison taken during check waveforms with the following time-dependencies typical of the various sensors and actuators of automotive control systems. Parameters of periodic signals Features an arbitrary signal  | Each removable using an oscilloscope signal can be described by the following basic parameters: - amplitude - the difference between the maximum and minimum voltage (V) signal within the period;
- period - cycle signal (ms);
- frequency - the number of cycles per second (Hz);
- width - the duration of the rectangular pulse (ms, ms);
- duty cycle - the ratio of the width to the repetition period (In foreign terminology used reverse duty cycle parameter called duty cycle, expressed as a%);
- waveform - a sequence of rectangular impulses, individual emissions, sine, sawtooth pulses, etc.
|
Typically, faulty device characteristics are very different from the standard, which allows the operator to easily and quickly visually detect the failed component. DC signals - only the voltage signal is analyzed. AC signals - are analyzed amplitude, frequency and waveform. The frequency-modulated signals - are analyzed amplitude, frequency, waveform, and the width of the periodic pulses. Signals, pulse width modulated (PWM), - analyze the amplitude, frequency, waveform and duty cycle of periodic pulses. Form outputted oscilloscope signal depends on many factors and can vary considerably. In view of the above, before attempting to replace the suspect component in case of a mismatch shot form the diagnostic signal with the reference waveform, you should carefully analyze the results. Voltage The zero level of the reference signal can not be regarded as absolute reference value - "zero" real signal depending on specific parameters of the circuit under test may be shifted relative to a reference (see. The range of 1 to illustrate the digital signal) within a specific range (see. The range 2 the illustration digital signal and one for illustration analog signal). The total amplitude of the signal depends on the supply voltage the circuit under test and may also vary with respect to the reference value within a certain range (see. The range of 2 to illustrate the digital signal and 2 illustrate the analog signal). In DC amplitude signal voltage is restricted. As an example of the stabilization circuit idling speed (IAC), a voltage signal which does not change with engine speed. In AC circuits, the amplitude of the signal already unequivocally depends on the frequency of the signal source. Thus, the amplitude of the signal output from the crankshaft position sensor (CKP) will increase with increasing engine speed. In view of the above, if the amplitude of shoot with an oscilloscope signal is too low or high (up to the upper levels of the cut-off), you just switch the operating range of the device by clicking on the appropriate scale of measurement. When checking the chain with e / m control (for example, the control system idling) when the power surges can occur (see para. 4 in the illustration digital signal) which can be safely ignored in the analysis of the measurement results. Do not worry as the appearance of the waveform deformations as mowing the bottom of the leading edge of the rectangular pulses (see para. 5 to illustrate the value of digital signal), unless, of course, the fact that flattening of the front is not a sign of infringement of serviceability of functioning of the inspected component. Frequency The repetition rate of the signal pulses dependent on the operating frequency of the source signals. Form removes the signal can be edited and brought to a convenient analysis mind by switching on the oscilloscope timebase scale image. When observing signals in AC circuits of the oscilloscope time base depends on the frequency of the signal source (see para. 3 to illustrate the range of analog signal) determined by the engine speed. As mentioned above, to bring the signal to a readable kind enough to switch out the time oscilloscope. In some cases, the characteristic signal changes are deployed with respect to the reference mirror dependencies that reversibility is due to polarity of the corresponding element and, in the absence of a ban on changing polarity can be ignored in the analysis. Typical signals of the engine control system components Modern oscilloscopes typically equipped with two signal lines coupled with a set of different probes, enables the connection of the device to almost any device. Red wire connected to the positive pole of an oscilloscope and is typically connected to terminal ECM. The black wire should be connected to a properly grounded point (weight). Injectors Management composition of air-fuel mixture in the modern automotive electronic fuel injection systems is accomplished by adjusting the duration of timely opening of the solenoid valves of injectors. Length of stay of injectors in an open state is determined by the duration of ECM produced electrical pulses applied to the input of e / m valves. The duration of the pulse is usually not outside the range 1 ÷ 14 ms. A typical pulse waveform controlling actuation of the injector is shown in illustration Injector fuel. Often on the waveform can be seen as a series of short pulsations following directly behind the initiating negative rectangular pulse and support e / m injector valve in the open position, as well as a sharp positive surge voltage that accompanies the closing of the valve. Serviceability of functioning ECM can be easily verified with an oscilloscope by visually observing changes in the shape of the control signal by varying the operating parameters of the engine. Thus, the pulse duration while cranking the engine idling to be somewhat higher than when the unit is at low revs. Increase the engine speed should be accompanied by a corresponding increase in the residence time of the injectors in an open state. This relationship is especially evident when you open the throttle quickly pressing on the gas pedal. With the help of a thin probe, connect the red wire to the injector oscilloscope terminal ECM. Probe the second signal wire (black) of the oscilloscope properly grounded. Analyse the form read out during engine cranking signal. Start the engine, check the shape of the control signal at idle. Slammed on the gas pedal, raise the engine speed to 3000 rev / min, - the duration of the control pulses at the time of acceleration should be significantly increased, followed by stabilization at a level equal to, or slightly less peculiar idle. Fast closing of the throttle must lead to a flattening of the waveform confirming the overlap injectors (for systems with a cutoff of fuel supply). At cold start the engine needs some rich air-fuel mixture that is provided by an automatic increase in the duration of opening of injectors. As the duration of the warm-up control pulses on the waveform must be continuously reduced, gradually approaching the typical value for the idle. In injection systems in which injector does not apply a cold start, cold start using additional control pulses that appear on the waveform of the pulsation of variable length. The table below shows the typical dependence of the duration of operating impulses of opening of injectors on the operating condition of the engine. Status Engine | The duration of the control pulse, ms | Idling | 1 ÷ 6 | 2000 ÷ 3000 rev / min. | 1 ÷ 6 | Full throttle | 6 ÷ 35 |
Inductive sensors |  | - Start the engine and compare the trace, taken from the output of the inductive sensor with the reference given in the illustration.
|
- The increase in engine speed must be accompanied by an increase in the amplitude of the pulse signal generated by the sensor.
|
|
Lambda sensor (oxygen sensor) | This subsection provides waveform, typical for the most commonly used in cars lambda probes zirconium type, which do not use a reference voltage of 0.5 V. In recent years become increasingly popular titanium sensors, which signal the operating range is 0 ÷ 5 V, with a high the voltage level is issued from the combustion of lean, low - enriched. |
| - Connect an oscilloscope between terminal lambda probe ECM and weight.
- Make sure the engine is at normal operating temperature.
 | - Compare the displayed waveform with a reference meter, shown in the illustration.
|
- If the recording signal is not uneven, and a linear relationship, then, depending on the voltage level, it indicates an excessive repauperization (0 ÷ 0.15 V) or pereobogaschenie (0.6 ÷ 1) an air-fuel mixture.
- If the idling engine holds the normal wavy signal, try several times to squeeze out sharply beadle gas - signal fluctuations should not go beyond the range of 0 ÷ 1.
- The increase in engine speed must be accompanied by an increase in the signal amplitude, reduction - reduction.
|
|
Ignition signal at the output of the ignition module | - Connect oscilloscope between terminals on the ignition ECM and weight.
- Warm up the engine to normal working temperature and leave its working on single turns.
 | - The screen of the oscilloscope should be given a sequence of rectangular pulses of DC. Compare the shape of the received signal with a reference, focusing attention coincidence parameters such as amplitude, frequency and pulse shape.
|
- With increasing engine speed signal frequency should be increased in direct proportion.
|
|
The primary winding of the ignition coil | - Connect an oscilloscope between the terminal of the ignition coil and ground.
- Warm up the engine to normal working temperature and leave its working on single turns.
 | - Compare the shape of the received signal with the reference - positive surges have to have a constant amplitude.
|
- Uneven surges can be caused by excessive secondary resistance, as well as faults in the I / O wire coil.
|
|
|
