The radio receives a vehicle speed signal from the electronic brake control module in order to correlate actual vehicle speed to the movement of the vehicle calculated by the navigation system and reported serial data.
Note: Diagnose any antilock brake system (ABS) related DTCs before performing this diagnostic.
1. Ignition OFF, disconnect the X4 harness connector at the A11 radio.
2. Ignition ON, operate the vehicle drive wheels at 5 mph. Test for 3-7 Hertz between the signal circuit terminal 20 and ground.
Ôçĺ If not within the specified range, test the signal circuit terminal 20 for an open, high resistance, short to ground or short to voltage. If the circuit tests normal replace the K17 electronic brake control module.
3. If the circuit tests normal, replace the A11 radio.'
X4 In the passenger compartment on the centre of the instrument panel, part of radio,
K17 Left rear of the engine compartment on strut tower