Vehicle: 2020 Ford Transit 250, RWD, V6-3.5L, Automatic Transmission/Transaxle

Mileage: 80,331 Miles

Problem: The vehicle came into the shop with the TPMS light on.

Case Details: The technician’s scan tool found two diagnostic trouble codes:

• B124D-02–a general signal failure in the TPMS sensor system
• B1182-00–BCM has lost communication with the TPMS network

The scan tool also revealed that all four TPMS sensors read 149.5 psi. A quick pressure check of all four tires validated that each one was 35 psi. The technician gave ALLDATA Tech-Assist a call for some diagnostic advice.

The Tech-Assist consultant said that because all four sensors read exactly 149.5 psi, this provided a valuable clue. That value is not an actual pressure reading, but rather, more like a default/failsafe placeholder indicating the body control module (BCM) or the Radio Transceiver Module (RTM) was not receiving valid RF data from any tire pressure sensor. Or, there was an electrical problem with one or both modules.

He suggested diagnosing the following possible causes:

1. RF interference
2. RTM issues
3. RTM power/ground issues
4. Antenna/coax concerns
5. BCM communication issues
6. Incorrect aftermarket sensors/frequency
7. Vehicle not actually seeing TPMS receiver data-attempt sensor activation with a TPMS trigger tool at each wheel. If no sensor responds, determine whether the sensors are the wrong frequency or if they’re dead.

While testing the power and grounds to the RTM, the technician found that there was no power. He discovered some broken wires near the connector at the RTM.

Confirmed Repair: The technician repaired the wires and was able to activate all four sensors. A quick test drive validated the TPMS system was repaired. Fixed!