E/D75B1, E/D75B2, E/D75B3

Fault Code E/D75B1, E/D75B2, E/D75B3





Malfunction indicated
Communication fault between the ASR and ETS control units

Fault symptom
TCS CTRL lamp on, no TCS function, Cruise Control not working, no KDW control, reduced engine power.

Test procedure

1 With all components connected, the engine running at idling speed and the car stationary, check the following voltages using a BOB:
a. ETS control unit pin 32 = approx. 5-7 Volt.
b. ETS control unit pin 29 approx 5-7 Volt.
c. ASR control unit pin 14 = approx. 5-7 Volt.
d. ASR control unit pin 2 = approx. 5-7 Volt.
The communication signal you measure is a DC reference of approx.10 V from one of the control units, the basic signal of which is pulsed by the other control unit.
The result is a signal voltage between 5 V and 7 V. If a voltage close to 0 V or 10 V is measured, this in dictates a broken lead or a short to earth.

Note: The above test can also be carried out using a logic probe which, on taking readings at the pins mentioned, should show "PULSE" steadily at the same time as "HI" and "LO" should flash.




2 With the ignition off and the ETS and ASR control units unplugged, check the communication leads as follows:
a. The YE lead between pin 14 of the ASR control unit and pin 29.
b. The Bk/WH lead between pin 2 of the ASR control unit and pin 32.

3 With the ignition switch in the Drive position and the two control units unplugged, check whether any of the leads are shorting to earth or battery voltage.

4 If no fault can be found and 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 ASR control unit that is known to be OK.

5 Try an ETS control unit which is known to be OK.