M9 Check Front Left Sensor Output at Brake Control Module

- Key OFF.

- Install 60-pin breakout box. Make sure the correct Econoline 4WABS overlay is installed.

- Remake the right front brake antilock sensor connection.

NOTE: Measurements of BOTH the frequency and the voltage output must be taken. The actual speed the wheels are turning is not important -- the result of voltage output divided by the frequency will not change with wheel speed. However, it is crucial that both the frequency measurement and the voltage measurement be taken at the same wheel speed.

- Set up the Rotunda 88 Digital Multimeter 105-00053 or equivalent, to measure the frequency (Hz) between Breakout Box Pin 34, Circuit 514 (Y/R) and Pin 8, Circuit 516 (Y/BK).

- Key ON and drive the vehicle slowly up to 20 mph. Measure and record the frequency once a stable vehicle speed of 20 mph has been reached.

- Change the meter to the A/C mV setting. Measure and record the voltage output at a stable vehicle speed of 20 MPH.

- Determine the right front brake antilock sensor output in mV/Hz: Output = (A/C Voltage) (Frequency)

- Is the sensor output greater than 13.0 mV/Hz?

YES -- Output at antilock brake control module is sufficient. Replace antilock brake control module. Go to M16. M16 Verify Concern Is Resolved

NO -- Sensor output at antilock brake control module is insufficient. Go to M10 to determine source of wiring fault. M10 Determine Location of Wiring Fault