With Integrated Fault-Diagnosis System (Flash Codes): 12245

Diagnostic procedure




1 With the ignition switch in the Drive position, select command code 555 on the ISAT scan tool. Alternatively, component testing can be carried out with the self-diagnostics function. Listen for the sound of the modulating valve working.

If it is working, continue with point 6.

2 If the modulating valve is not working, unplug its connector and take a resistance reading across the pins.

The reading obtained should be about 30 ohms. If it is not, change the modulating valve.

3 With the ignition switch in the drive position, check that battery voltage is present on pin 2 of the modulating valve.




If it is not, check the lead between pin 2 of the modulating valve connector and pin 87 of the main relay.

4 Plug in the Breakout Box (LH control module not connected). Check the lead between pin 1 of the modulating valve connector and pin 19 of the control module connector.

5 If the leads are OK, try fitting a new control module.




6 With the modulating valve and control module connected, unplug the connector for the temperature sensor in the EGR system.

Run the engine at idling speed and check that the resistance of the temperature sensor is several megohms.

Build up a vacuum in the valve through the hose marked red that is connected to the EGR valve. At the same time, check that the resistance of the temperature sensor drops to kohms.

If it does not, change the EGR valve (the temperature sensor is incorporated in the EGR valve).

7 Plug in the Breakout Box (LH control module not connected). Check the lead between pin 1 of the temperature sensor connector and pin 23 of the LH control module connector.

Check the lead between pin 2 of the temperature sensor connector and ground.




8 If the fault persists, continue by checking the vacuum hoses as follows:
a. With the engine running, disconnect the hose marked red from the modulating valve to the intake manifold.

b. Build up a vacuum in the hose.

If engine speed now drops, the EGR valve is OK.

If it does not, check the hose, connections and vacuum tank.

c. Also check that a vacuum is present in the hose marked white connected to the modulating valve.

If no vacuum is present, check the hose, connections and vacuum tank.