Fuel Supply-Pressure Up to Mechanical High-Pressure Pump, Checking

Fuel Supply-pressure Up To Mechanical High-pressure Pump, Checking

NOTE:
- Fuel pump (FP) control module OK
- Fuel Pump (FP) OK
- Fuel filter OK
- Battery voltage at least 11 Volts

- Switch ignition on.

NOTE: As follows, the engine control module (ECM) is selected with the VAS 5051, then the display group 140 is selected under function "Read measuring value block".







- Connect vehicle diagnosis, testing and information system VAS 5051 A with diagnostic cable VAS5051/1.







- Press button "On-Board Diagnostics".







- In selection -1-, press vehicle system "01 - Engine electronics".







- In selection -1-, click on diagnostic function "08 - Read measuring value block".
1. Selection of diagnostic functions:







- In button field -2-, select display group 140 and confirm input by pressing Q button.







Display group 140:
1. Display group 140
2. Display field 1

- Display field 2
- Display field 3
- Display field 4

Observe indication in display field 3. The indication shows actual pressure (current pressure) in fuel rail.

NOTE: By switching the ignition off and on the Fuel Pump (FP) Control Module J538 activates the fuel pump for several seconds. Only during this time, can the fuel supply-pressure be measured.

- Switch ignition off and immediately on again (if an advisory message appears "relative to switching ignition off and on" press Repeat).
- Measure fuel pressure.

Specification: approx. 6 bar (5 to 7 bar) positive pressure

- If specified value is not attained, check delivery rate of electrical fuel pump.