With Integrated Fault-Diagnosis System (Flash Codes): 12241

Diagnostic procedure, LH 2.4, 2.4.1 and 2.4.2

Important: The fault might be due to one of the cylinders not firing. Ignition system fault diagnosis may therefore also be necessary.

For fault diagnosis, see also "Checking the injectors". [1][2]Checking Injector Flow Capacity

If the ISAT scan tool is not used, go to point 2.




1 With the ignition switch in the ON position, select command code 552 on the ISAT scan tool. Alternately, component testing can be carried out with the self-diagnostics function.

Check that all injectors are working (15 Hz) by listening to them.

If they are working, continue fault diagnosis but bear in mind that intermittent faults may occur.

2 Ignition switch in the OFF position. Unplug all injector connectors. Connect a test LED to the connector of each injector (one at a time). Run the starter motor, check that the test LED flashes.

If it flashes, go to point 3.

If it does not, go to point 4.

3 With the connectors unplugged, take a resistance reading across the injector connector pins. The reading obtained should be 10 - 20 ohms. If it is not, change the defective injector.




4 With the ignition in the ON position, check that battery voltage is present on pin 1 of each injector connector.

If it is, go to point 5.

If it is not, check the lead between pin 1 of each connector and pin 87 of the main relay.

5 With the ignition switch in the OFF position and the LH control module unplugged, check the lead between pin 2 of each injector and pin 18 (LH 2.2 pin 13) of the connector.

6 Carry out flow capacity measurement, see "Checking injector flow capacity". [1][2]Checking Injector Flow Capacity

7 If the fault persists in spite of this, try fitting a new control module.

Note: If an injector is disconnected, the engine will be running on a richer mixture.