Bosch CDi pressure regulation valve

You will require a PicoScope to perform this test. A list of suitable accessories can be found at the bottom of this page.

How to perform the test

Plug the BNC test lead into Channel A on the PicoScope. Place a black clip onto the black probe (negative) and connect this to a suitable ground point. Connect a Back-pinning Probe to the coloured lead (positive) in order to backpin the connector at the pressure regulation valve, as illustrated in Figure 1. If a suitable automotive break out lead is available, this may be used instead of the back pinning method.

The valve will have two electrical connections: an ignition positive (15 V) and a switched earth.

Example waveform

Waveform notes

The Common-rail Diesel Injection (CDi) pressure regulation valve is an actuator. It is commonly supplied with an ignition live (15 V) and a duty cycled ground, provided by the CDi control unit, that controls the pressure.

Technical information

Most common rail systems now employ a pressure regulation valve. This can be located either on the high-pressure pump or on the common rail itself.

The pressure regulation valve serves with the quantity control valve to control the common rail pressure. The pressure relief valve simply allows more or less high pressure fuel to flow into the back leak system thus increasing or decreasing the fuel pressure in the rail.

Should you suspect a fault with the signal, test the wiring from the CDi control unit to the pressure regulation valve.

Ensure that the CDi control unit has good power supplies and grounds where required or specified.

Faulty waveforms - troubleshooting

Should you suspect a fault with the signal, test the wiring from the CDi control unit to the pressure regulation valve.

Ensure that the CDi control unit has good power supplies and grounds where required or specified.

AT055-2

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

  • Back-pinning Probe Set

    £48.00

  • Flexible Back-pinning Probe

    £7.00

  • PicoScope Battery Clip

    £5.00

  • Large Dolphin/Gator Clips

    £10.00

  • Premium Test Lead: BNC to 4 mm, 3 m

    £48.00

  • Premium Test Leads: Set of four leads 3 m (TA125 - TA128)

    £179.00

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Guided test: Bosch CDi pressure regulation valve