Fault in the fuel flow control solenoid valve – KIA Engine J3 2.9 CRDi

MAKES AND MODELS AFFECTED

KIA:

KIA CARNIVAL / GRAND CARNIVAL III (VQ) 2.9 CRDi (J3) 136 kW (185 CV) ’06-

The manufacturing date of the affected vehicles: 

03.2006 (start of production) to 10.12.2007.

SYMPTOMS

The symptoms that may be found are the following:

• Engine fault indicator light (EOBD) on.

• Fault message on the instrument panel multifunction screen.

• The engine control unit enters an emergency/reduced power phase.

The following fault code is recorded on the diagnostics machine:

P0088 – Pressure too high in the fuel common rail. 

There may be more associated fault codes seen on the diagnostic machine.

CAUSE

Failure of the high pressure fuel pump inlet metering valve (IMV).

CHECK

To describe the checks to carry out on the fuel system component, we will use the information contained on platform http://www.dis-net.com (information system for the diagnostic) to help us.

First check

Due to the fault code recorded by the diagnostic machine, the high pressure fuel sensor should be checked first. 

Using a tester or multimeter and with the vehicle ignition on, check the sensor power supply voltage. Connect the positive tip to sensor pin 3 and the multimeter common to pin 2 or the battery ground.

Sensor power supply voltage check (information extracted from www.dis-net.com)

The correct power supply voltage should be 5 volts approximately, if this is the case, go to the next check. If not, check the wiring and the state of the system.

Second check

Using a multimeter and with the vehicle engine started, check the sensor signal voltage. Connect the positive tip to pin 1 of the solenoid and the multimeter common to the battery ground.

Sensor signal voltage check (information extracted from www.dis-net.com)

The voltage of the signal that the sensor transmits must increase as the pressure inside the fuel system common line increases. Below is a table and graph with the theoretical sensor operating values.

*The values displayed above can be compared with the true values provided by the diagnostic machine. If the comparison is positive, we can assume the sensor is operating correctly.

The signal provided by the sensor to the engine control unit is what determines the regulation of the high pressure fuel pump flow. For this reason, if the fault has not been found in the pressure sensor, then this solenoid valve should be checked.

Third check

Using a multimeter and with the vehicle ignition on, check the solenoid valve power supply voltage. Connect the positive tip to pin 1 of the solenoid valve and the multimeter common to ground.

Solenoid valve power supply voltage check (information extracted from www.dis-net.com)

The correct power supply voltage should be 12 volts approximately, if this is the case, go to the next check. If not, check the wiring and the state of the system to see if it is defective.

Fourth check

Using an oscilloscope and with the engine started, check the solenoid valve signal. Connect Channel 1 - CH 1 of the oscilloscope to pin 2 of the solenoid valve and the common to negative.

Solenoid signal check (information extracted from www.dis-net.com)

The oscilloscope should display a square wave signal, RCO type of 12 V. The amplitude of the signal will vary in relation to the engine load, i.e. the signal dwell will indicate the activation time of the solenoid valve, where the fuel flow regulation will be modified constantly depending on the pressure in the common fuel line.

Operating values:

· The engine at idle, the duty cycle percentage is 32% or 68% in dwell.

· The engine in the acceleration phase, the duty cycle is 30% or 70% in dwell.

The duty cycle is the time that the solenoid is positive (not actuated). So, the shorter the time, the longer will be the activation to ground of the solenoid and the regulation will increase.

If the oscilloscope does not display the signal correctly or indicates a wrong value, the fault is coming from the same solenoid that is not regulating correctly.

SOLUTION

 The repair procedure is as follows:

- Check the parameters indicated on the diagnostic machine.

- Check the state both of the high pressure fuel sensor and the fuel flow control solenoid valve.  

- Replace the fuel flow control solenoid valve - Reference: 331154X400QQK. Consult your official distributor.

- Clear the fault codes recorded on the diagnostic machine.