2/42440,2/42441,2/42442,2/42450,2/42451,2/42452

Fault codes 2/42440, 2/42441, 2/42442, 2/42450, 2/42451, 2/42452, 2/42460, 2/42491, 2/42492





Malfunction indicated
Incorrect fuel-air mixture

Fault symptom
Poor driveablity because the fuel-air mixture is too rich or too lean.
CHECK ENGINE lamp alight.

Test procedure

Note: During the car's running-in period (up to 500 km), any of these fault codes may be generated without any fault actually existing. In these cases, check carefully to see whether the fault code is generated again after it has been cleared.

1 With the engine warmed-up, enter command code 205 on the ISAT. The following codes should appear on the display one after the other in a continuous cycle.
- 8B105 (lean)
- 8B305 (rich)
- 8B005 (inactive)

If any of the codes is displayed continuously, it indicates that the Lambda sensor is not working properly.

2 Check whether battery voltage is present across the pins of the Lambda sensor connector.

If voltage is present, go to point 3. If riot, check:
- fuse No.1 of the Lambda sensor.
- the BU/RD lead between pin 1 and fuse No.1 of the Lambda sensor connector for continuity / shorting.
- the BK lead between pin 2 of the Lambda sensor connector and ground for continuity/shorting.

3 With the ignition switched off, unplug the Lambda sensor preheating connector and measure the resistance across the sensor connections (WH-WH).

The resistance should be 4-8 ohms. In the event of an open circuit or high resistance, fit a new Lambda sensor.

4 Check the induction system for leaks by listening for the sound of air escaping.

5 Check the fuel pressure and operation of the fuel pressure regulator.

Relative to the pressure in the inlet manifold, the fuel pressure should be:
- 3.0 bar (all LH 2.4.2)
- 2.5 bar (LH 2.4 Turbo)
- 3.0 bar (LH 2.4 i)

If the fuel pressure is incorrect, fit a new pressure regulator.

6 With the engine idling, measure the sensor signal across pin 24 of the control module and a good grounding point. The signal should swing between 0 and 0.4 V (lean) and 0.6-1.0 V (rich) when the engine is hot. If it does not, check the GN and BK leads between pin 24 of the control module and the Lambda sensor for continuity/shorting.

7 If the fault persists in spite of the above tests, fit a new Lambda sensor and check system operation afresh by entering command code 205 on the ISAT.

8 Try a new control module.