The purpose of this test is to monitor the injector voltage within a multi-point injection system.
This test involves measuring a potentially hazardous voltage.
Please ensure you follow manufacturers' safety instructions and working practices and ensure the rated voltage for all accessories you are using meets or exceeds the expected voltage.
To avoid possible damage to your scope, you may need to use an attenuator for this test.
Scopes with a 200 V range, such as PicoScope 4x25 models, do not need an attenuator for this test.
All other PicoScope Automotive models need an attenuator on the channel input. You can use either a 10:1 or a 20:1 attenuator provided that you adjust the PicoScope software accordingly. Select from the appropriate Channel Options menu:
This known good waveform has the following characteristics:
Initially, the waveform voltage on the switched-earth side of the injector is at battery voltage, 14 to 15 V, and the injector is off.
At 0 ms, the Engine Control Module (ECM) provides an earth path to battery negative, 0 V, which marks the start of injection.
With the engine at normal operating temperature and idling, the injection duration is about 4.25 ms.
When the injector is switched off at 4.25 ms, there is a spike in the waveform voltage which peaks at about 85 V.
At about 1 ms after injector switch-off, there is a hump in the decaying voltage spike.
The waveform voltage remains at battery positive until the next start of injection.
An indirect injector delivers the correct quantity of atomised fuel to the air in the inlet tract, as it is drawn through to a cylinder.
A multi-point injection system has one injector per cylinder supplied by a common fuel rail. As the rail pressure regulator maintains a constant pressure the injected fuel quantity depends only on injection duration.
The ECM uses input signals from a range of sensors dependent on both system type and manufacturer application in order to calculate injection duration.
Indirect injectors employ solenoid-controlled valves, which work against a spring force acting to close them. The valves open when sufficient current flows through their circuit. The injector valve will not open fully if there is insufficient current.
An ECM, or dedicated control module, dictates the current flow in each injector circuit by switching in and out the individual injector earth paths.
When current flows, an injector solenoid builds and stores energy, until it is saturated. When the current flow stops, the stored energy is returned to the circuit, inducing a large voltage spike. The voltage spike varies from vehicle to vehicle; some injector circuits include a Zener diode or a resistor-capacitor combination that limits, or squares-off, its peak.
The decay of the voltage spike is sometimes momentarily interrupted by the action of the valve as its spring forces it rapidly back to its closed position. This indicates normal movement of the injector valve.
There are two types of multi-point injection system:
Selection of component related Diagnostic Trouble Codes (DTCs):
P0200 – Injector Circuit Malfunction
P0201 – Injector Circuit Malfunction – Cylinder 1
P0202 – Injector Circuit Malfunction – Cylinder 2
P0203 – Injector Circuit Malfunction – Cylinder 3
P0204 – Injector Circuit Malfunction – Cylinder 4
P0205 – Injector Circuit Malfunction – Cylinder 5
P0206 – Injector Circuit Malfunction – Cylinder 6
P0207 – Injector Circuit Malfunction – Cylinder 7
P0208 – Injector Circuit Malfunction – Cylinder 8
P0209 – Injector Circuit Malfunction – Cylinder 9
P0210 – Injector Circuit Malfunction – Cylinder 10
P0211 – Injector Circuit Malfunction – Cylinder 11
P0212 – Injector Circuit Malfunction – Cylinder 12
P0213 – Cold Start Injector 1 Malfunction
P0214 – Cold Start Injector 2 Malfunction
P0216 – Injection Timing Control Circuit Malfunction
P020A – Cylinder 1 Injection Timing
P020B – Cylinder 2 Injection Timing
P020C – Cylinder 3 Injection Timing
P020D – Cylinder 4 Injection Timing
P020E – Cylinder 5 Injection Timing
P020F – Cylinder 6 Injection Timing
P021A – Cylinder 7 Injection Timing
P021B – Cylinder 8 Injection Timing
P021C – Cylinder 9 Injection Timing
P021D – Cylinder 10 Injection Timing
P021E – Cylinder 11 Injection Timing
P021F – Cylinder 12 Injection Timing
P0261 – Cylinder 1 Injector Circuit Low
P0262 – Cylinder 1 Injector Circuit High
P0263 – Cylinder 1 Contribution/Balance Fault
P0264 – Cylinder 2 Injector Circuit Low
P0265 – Cylinder 2 Injector Circuit High
P0266 – Cylinder 2 Contribution/Balance Fault
P0267 – Cylinder 3 Injector Circuit Low
P0268 – Cylinder 3 Injector Circuit High
P0269 – Cylinder 3 Contribution/Balance Fault
P0270 – Cylinder 4 Injector Circuit Low
P0271 – Cylinder 4 Injector Circuit High
P0272 – Cylinder 4 Contribution/Balance Fault
P0273 – Cylinder 5 Injector Circuit Low
P0274 – Cylinder 5 Injector Circuit High
P0275 – Cylinder 5 Contribution/Balance Fault
P0276 – Cylinder 6 Injector Circuit Low
P0277 – Cylinder 6 Injector Circuit High
P0278 – Cylinder 6 Contribution/Balance Fault
P0279 – Cylinder 7 Injector Circuit Low
P0280 – Cylinder 7 Injector Circuit High
P0281 – Cylinder 7 Contribution/Balance Fault
P0282 – Cylinder 8 Injector Circuit Low
P0283 – Cylinder 8 Injector Circuit High
P0284 – Cylinder 8 Contribution/Balance Fault
P0285 – Cylinder 9 Injector Circuit Low
P0286 – Cylinder 9 Injector Circuit High
P0287 – Cylinder 9 Contribution/Balance Fault
P0288 – Cylinder 10 Injector Circuit Low
P0289 – Cylinder 10 Injector Circuit High
P0290 – Cylinder 10 Contribution/Balance Fault
P0291 – Cylinder 11 Injector Circuit Low
P0292 – Cylinder 11 Injector Circuit High
P0293 – Cylinder 11 Contribution/Balance Fault
P0294 – Cylinder 12 Injector Circuit Low
P0295 – Cylinder 12 Injector Circuit High
P0296 – Cylinder 12 Contribution/Balance Fault
This help topic is subject to changes without notification. The information within is carefully checked and considered to be correct. This information is an example of our investigations and findings and is not a definitive procedure. Pico Technology accepts no responsibility for inaccuracies. Each vehicle may be different and require unique test settings.
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