The injection control pressure regulator valve is a pulse width (Duty cycle %) modulated valve operating at 400 Hz. The pulse width is modulated between 8 to 60% to control ICP pressure in the range of 3.4 to 20 kPa (500 to 3000 lb/in.2
). The regulator is mounted in the high pressure pump and maintains desired injection control pressure by dumping excess oil through a (internal shuttle) spool valve into the front cover and back to the oil pan.
As the demand for injection control pressure increases, the ECM increases the pulse width (duty cycle %) over the IPR solenoid. This action forces the poppet against the drain orifice increasing the pressure behind the spool valve.
As oil pressure increases behind the spool valve, it moves forward and blocks the drain ports on the sides of the IPR valve. See Figure
“IPR Higher Injection Pressure”
. When the demand for injection control pressure decreases, the ECM decreases the duty cycle %) over the solenoid allowing oil to drain out of the drain orifice. This action is accomplished by relieving the pressure behind the spool valve that allows it to partially open the relief port, decreasing the injection control pressure. See Figure
“IPR Lower Injection Pressure”
.
The described operation allows the IPR to continuously adjust injection control pressure commanded by the ECM. (The Injection Control Pressure Sensor is referred to as both the ICP and the IPS sensor. Both are correct.)

1. Solenoid Windings | 4. O-rings |
2. Poppet Valve | 5. Spool Chamber Drain |
3. Spool Valve | |
Figure 1. IPR Higher Injection Pressure

1. Solenoid Windings | 4. O-rings |
2. Poppet Valve | 5. Spool Chamber Drain |
3. Spool Valve | |
Figure 2. IPR Lower Injection Pressure
Series 40E Troubleshooting Manual – 6SE241 |
Generated on 10-13-2008 |