4/24260, 4/24261, 4/24290, 4/24291
Fault Code 4/24260, 4/24261, 4/24290, 4/24291Malfunction indicated
Speed signal absent or faulty
Fault symptom
Cruise Control system not working
Test procedure
Note: If the car has been driven under abnormal conditions, e.g. on rollers, first check the 10 A fuse (red) in the ABS fuse holder.
1 With the adapter lead, part No.86 11 048, connected, enter ISAT command code 280.
ISAT should now display the current speed, e.g. 80070 70 km/h.
If it does not, check the GN/RD and GN leads between the speed transmitter (132) and pin 10 of the connector for continuity or shorting to earth.
2 Check that the speedometer is in working order.
If not, unplug its 2-pole connector and measure the signal voltage from the speed transmitter(on the gearbox). The multimeter should be set to measure AC.
As the speed increases, the signal voltage should also increase within a range of between 0V and 5V.
3 Check that the EDU, which also uses the speed signal, is in proper working order.
If it is not, check that voltage is present on pin 1 of the speedometer and that pin 3 is earthed.
4 Using a BOB, check the speed pulses on pin 10 of the connector with the wheels alternately rotating and stationary.
With the wheels stationary, the signal voltage should be 0 or 12 V (depending on the position of the wheel) and with the wheels rotating it should be about 6 V (DC).
5 Check that the control unit's earthing point on the engine is OK.
6 With the control unit connected and the engine idling, use a BOB to check that no interference (pulses) is present on the lead to pin 10. Use the ISAT PULSE function for this test.
If interference is present, check the lead to pin 10 for shorting to earth/+ 12 V.
7 If the above tests check Out OK, clear the fault code and drive the car to see whether it is generated afresh. If it is, try fitting an ETS control unit that is known to be OK.
8 Try a TC/ABS control unit which is known to be OK.