Vehicle: 2011 Ford F-150, 4WD, V6-3.5L Turbo, Automatic Transmission
Problem: The customer brought the truck in with the ABS lamp on.
Details: The tech pulled Diagnostic Trouble Codes C109E (vacuum sensor circuit fault) and B1596 (service continuous codes are set in ABS module). The tech checked the following items to ensure they were consistent factory standards:
Brake booster vacuum level (BBVACLVL) PID in scan tool data – it did not match actual engine vacuum
Five volts at brake booster sensor GY/YE wire – 5 volts were present
Good ground at brake booster sensor BK-GN wire – it had a solid ground
Back-probed brake booster sensor pin #1 with voltmeter and compared with BBAVACLVL sensor reading in scan tool – they were not the same reading
Checked the GN/BN wire between brake booster sensor and ABS module pin #10 for open/short circuit
Confirmed Repair: The tech traced the open circuit to a broken GN-BN wire that was about 12 to 18 inches from the brake booster sensor. He repaired the wire and cleared the codes. He confirmed the repair with a test drive. Fixed!