CRD solenoid injector (Delphi): current

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

Connection guidance

Connection for diagnostic work will vary dependent on application.

Technicians should whenever possible gain access to the test circuit without damage to seals and insulation. If this is not possible then make sure appropriate repairs are completed.

General connection advice

PicoScope offers a range of options within the test kits.

Dependent on the difficulty of access, choose from:

  1. Breakout leads.
  2. Back-pinning probes.

Testing sensors and actuators (to include relevant circuit/connectors):

  • When testing a sensor, it is desirable to gain access at the control module.
  • When testing an actuator, it is desirable to gain access at the actuator.

How to perform the test

  1. Connect the low amp current clamp into Channel A on your PicoScope. Switch on the current clamp and select the 20 A scale. Zero the current clamp before connecting to the vehicle.
  2. Minimise the help page and with the example waveform on your screen PicoScope has already selected suitable scales for you to capture a waveform.
  3. Start and run the engine at idle.
  4. Start the scope.
  5. Vary the accelerator pedal position as necessary to view idle, engine acceleration and overrun injector waveforms.
  6. With your live waveform on screen, Stop the scope.
  7. Turn off the engine.
  8. Use the Waveform Buffer and Zoom tools to examine your waveforms.

Waveform notes

These known good waveforms have the following characteristics:

All injection events begin with a twin peaked current around 18 A to open the injector.

With the engine idling there are two pilot injections and one main injection.

The pilot and main injection events have an additional phase of lower current, which modulates from 5.5 to 7.5 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.

Note: under some load and demand conditions, only one pilot injection might be observed (rather than two seen in the examples).

Waveform Library

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

Example Delphi injector.

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

GT099

Disclaimer
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.

Suitable accessories

  • 20 A / 60 A DC (low amps) current clamp

    £111.00

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Guided test: CRD solenoid injector (Delphi): current