Products suited to this guided test*
  • 20 A / 60 A DC (low amps) current clamp

  • *At Pico we are always looking to improve our products. The tool used in this guided test may have been superseded and the product above is our latest version used to diagnose the fault documented in this case study.

CRD (Bosch) solenoid injector circuit current

The purpose of this test is to check the actuation current within a Bosch-type Common Rail Diesel (CRD) solenoid injector circuit across a range of engine load and demand conditions.



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.


How to perform the test

View connection guidance notes.

  1. Connect the low amp clamp into PicoScope Channel A.
  2. Select the 20 A scale and zero the clamp before connecting to the injector supply circuit.
  3. Minimize the help page. You will see that PicoScope has displayed an example waveform and is preset to capture your waveform.
  4. Start the scope to see live data.
  5. Start the engine and allow it to idle.
  6. Vary the accelerator pedal to see idle, acceleration and overrun injector waveforms.
  7. With your waveforms on screen stop the scope.
  8. Turn off the engine.
  9. Use the Waveform Buffer, Zoom and Measurements tools to examine your waveform.


The orientation of the clamp relative to the wire will determine whether it has a positive or negative output. If a live waveform does not appear on your screen, or appears to be inverted, try reversing the orientation of the clamp.

Example waveform

Engine at idle.

Engine at high speed.

Engine on overrun.

Waveform notes

These known good waveforms have the following characteristics:

  • All injection events begin with a peak current in the range 16 to 18 A to open the injector.
  • With the engine idling there are one or two pilot injections and one main injection.
  • The pilot and main injection events have an additional phase of lower current, which modulates from 12 to 14 A. This retaining current holds the injector in its open position.
  • The retaining current of the main injection increases in duration with increasing torque demand (as signalled by changes in the accelerator pedal position); however, the pilot injection retaining current does not.

Waveform Library

Go to the drop-down menu bar at the lower left corner of the Waveform Library window and select Injector current.

Further guidance

A common rail diesel injector delivers atomised fuel directly to the combustion chamber.

Injection timing and quantity is controlled by the Engine Control Module (ECM). Common rail diesel solenoid injectors can be actuated independently of the pressure generating mechanism, unlike their counterparts within distributor pump or unit injector (i.e. Pumpe-Düse or PD) systems, which can only operate within periods of high pumping pressure. This characteristic facilitates multiple injection events per engine cycle and permits additional functionality:

  • Pilot injection which delivers a small quantity of diesel prior to the main injection event to better regulate the build-up of combustion pressure and reduce diesel knock; and
  • Post injection to facilitate exhaust gas treatment processes.

In order to facilitate their rapid operation, injector switching circuit voltages are quite high, typically 50 to 90 V.

Furthermore, the injector solenoids are rapidly energised using charge drawn from a combination of the vehicle power supply system and capacitors. The capacitors are charged by the circuit voltage induced by the solenoids when the supply voltage is removed.

Common rail diesel injectors are susceptible to mechanical and electrical faults, producing a variety of symptoms:

  • Cylinder sealing: if the interface between the injector and the cylinder head is not properly sealed, unburnt or partially burnt gasses and soot can escape from the cylinder during compression and combustion, causing blow-by and reduced cylinder pressures/combustion temperatures, which, in turn, can cause excessive exhaust smoke.
  • Internal sealing: if an internal seal has failed, fuel will leak from the supply side through to the return side, causing possible high pressure supply issues, such as a reduced pressure during cranking (where the high pressure pump speed and its ability to generate sufficient flow is limited).
  • Electrical circuits: if an injector solenoid cannot energise sufficiently then it’s valve may not open properly, which may cause misfire symptoms.
  • Contamination: engine issues causing excessive soot or contamination within the engine may affect the injector outlet, which can affect their flow and spray patterns.

Diagnostic trouble codes

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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Guided test: CRD (Bosch) solenoid injector circuit current