2011 Ford F550 Super Duty
Mileage
262,645
Service Date
10/7/2025
Services Performed
- We first scanned for codes and found an open circuit code for all 8 injectors. We then removed one glow plug and checked the resistance in the glow plug and found that it is with specification. We then cycled the ignition on with a multi meter connected to the glow plug wire and found it did not have power. We then un plugged the glow plug control module and found no obvious faults or bad connections. We then checked the wires at the control module to the glow plugs and found that they all had an open circuit. We then located a brake out connector in the engine compartment for the glow plug harness. We checked it and found it was not plugged in correctly. We reconnected the brake out plug and retested the glow plugs and found that they are now operating according to specification.
- We scanned for codes and found a invalid data received code in the ECM. We then checked for power and ground at the ABS control module and found both are present, we also checked wiring near the module and under the hood related to the ABS. We then test drove the vehicle and monitored live data and found that the speed sensor at the differential is erratic and momentarily drops off. We need more time to properly diagnose this problem.
- We put the vehicle up on jack stands and unplugged the speed sensor, connected a scope to the sensor and found a normal wave form with the vehicle in drive. We then monitored wheel speed data while wiggling the the harness for the rear wheel speed sensor. We found that the signal stops when pulling on the harness. We found a faulty connector in the harness in between the fuel tank and the frame. We repaired the harness, test drove the vehicle, and found that the wheel speed signal is now consistent, and no codes returned.
Brandon K. gave our service a 5 star review on 10/8/2025
