2/45641, 2/45651, 2/45691

Fault codes 2/45641, 2/45651, 2/45691





Malfunction indicated
Signal from mass air flow sensor faulty or absent.

Fault symptom
Poor driveablity, starting difficulty and high fuel consumption. Fault code often appears together with other fault codes.
CHECK ENGINE alight.

Test procedure

1 Enter command code 22A on the ISAT and check that the display shows the following:
- 802.0 = 2.0 V on idling
- 805.0 = 5.0 V on full throttle

2 Check the induction system for leaks by pressurizing it and listening for the sound of air escaping.

3 Check that pin 1 of the mass air flow sensor has a good connection to ground.

If not, check the BK lead between pin 1 of the mass air flow sensor and ground for continuity/ shorting.

4 With the ignition switch in the Drive position, check whether battery voltage is present on pin 5 of the mass air flow sensor.

If it is not, check the BN/WH lead between pin 5 of the mass air flow sensor and pin 87 of the main relay for continuity/shorting.

5 Enter command code 22A on the ISAT and check that the signal varies between 2 and 5 V, depending on the load (the display should show 802.0-805.0).

If it does not, check the OG lead between pin 7 of the control module and pin 3 of the mass air flow sensor for continuity / shorting.

6 Check that pin 2 of the mass air flow sensor is properly grounded.

If it is not, check the BU/WH lead between this pin and pin 6 of the control module for continuity / shorting.

7 If no faults have been found after carrying out the above tests, clear the fault codes and take the car out on a road test. Afterwards check whether the fault codes have been recorded afresh.

8 Fit a new mass air flow sensor and repeat the procedure described in point 6.

9 Try a new LH control module.