Fuel Pressure Regulator Valve, Checking

Fuel Pressure Regulator Valve, Checking

Recommended special tools and equipment
- VAG1526 multimeter or VAG1715 multimeter
- VAG1594 connector test kit
- Wiring diagram

Test requirements







- Corresponding fuses on E-box in engine compartment, left side, for Fuel Pressure Regulator Valve -N276- must be OK:

NOTE: Fuses on this fuse holder are labelled "SB" in the wiring diagram.

- Engine Component Power Supply Relay -J757-, relay position R3, must be OK, check.
- Ground (GND) connections between engine and chassis must be OK.
- Coolant temperature must be at least 80 degrees C; PID 5 ($5), Coolant temperature.
- Ignition switched off.

Function test
Observe safety precautions.
Observe rules for cleanliness.

- Connect diagnostic tester.
- Start engine and let run at idle.
- Under address word 33, select "Diagnostic mode 1: Checking measured values.
- Select measuring value "PID 35 ($23): Fuel pressure (rail pressure)".
- Check specified value of fuel pressure (rail pressure) at idle:







- End diagnosis and switch ignition off.

If specified value is not obtained:
- Remove engine cover, removing and disassembling air filter/engine cover.







- Disconnect 2-pin connector -2- from Fuel Pressure Regulator Valve -N276-.

Checking resistance
- Check resistance between valve terminals.

Specified value: 1.0 to 5.0 Ohms

If specified value is not obtained:
- Replace high pressure pump with Fuel Pressure Regulator Valve -N276-.
- Erase DTC memory of Engine Control Module (ECM). Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If specified value is obtained:
- Check wires to Engine Control Module (ECM) according to wiring diagram.

Checking wires to Engine Control Module (ECM)
- Connect test box to 60-pin connector of wiring harness. Test Box, Connecting For Wiring Test

Engine Control Module (ECM) is not connected.







- Check wire between test box and 2-pin connector to Engine Control Module (ECM) for open circuit according to wiring diagram.

Terminal 2 + socket 19

Wire resistance: max. 3.0 Ohms

- Check the wire for short circuit to B+ and to Ground (GND).

Specified value: Infinity Ohms

- Check wire between 2-pin connector terminal 1 and Engine Component Power Supply Relay -J757- for open circuit according to wiring diagram.

Wire resistance: max. 3.0 Ohms

- Erase DTC memory of Engine Control Module (ECM). Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If no malfunctions are found in wires:
- Replace Engine Control Module (ECM) -J623-