Pinpoint Test C : Diagnosing Radio Frequency Interference Faults

WARNING: This page is about a different car, the 2018 Ford Fiesta. However, it is still accessible from the selected car via links, so may be relevant.

Normal Operation and Fault Conditions
When the TPMS sensor is activated by the sensor training tool, the sensor transmits the current tire pressure and sensor identification to the BCM. RFI or a sensor with an internal failure prevents the sensor from transmitting the information to the BCM. Likewise, a BCM with an internal failure prevents the sensor information from reaching the BCM.

Possible Sources
- RFI
- TPMS sensor
- BCM
Visual Inspection and Pre-checks
- Inspect for customer electronic devices, such as a cell phone charger or GPS unit.
- Inspect for aftermarket wheels or run-flat tires (tires with steel body cord plies in the tire sidewall).

C1 VIEW THE BCM (BODY CONTROL MODULE) TIRE PRESSURE MONITORING SYSTEM STATUS (TPMS_STAT) PID (PARAMETER IDENTIFICATION)
- Ignition ON.
- Using a diagnostic scan tool, view the BCM TPMS_STAT PID.
Does the BCM TPMS_STAT PID display SYSTEM FAULT?

Yes GO to C2

No GO to C4

C2 CARRY OUT THE TPMS (TIRE PRESSURE MONITORING SYSTEM) SENSOR TRAINING PROCEDURE

NOTE: Before beginning TPMS sensor training, make sure the vehicle is away from other vehicles or devices that might cause RFI such as electric motors or radio transmitters.

Train all 4 TPMS sensors. REFER to: Tire Pressure Monitoring System (TPMS) Sensor Location Calibration .

Did all of the TPMS sensors transmit correctly and did the horn sound when each sensor transmitted to the BCM?

Yes	The system is operating correctly at this time. The concern may have been caused by RFI. REFER to: Tire Pressure Monitoring System (TPMS) - System Operation and Component Description .

GO to C3

C3 ATTEMPT TO CARRY OUT THE SENSOR TRAINING PROCEDURE AGAIN USING KNOWN GOOD SENSORS

Move the vehicle to rotate the wheels at least one-fourth of a turn. Leave the vehicle doors open.

Attempt to train known good TPMS sensors from another vehicle to the concern vehicle. REFER to: Tire Pressure Monitoring System (TPMS) Sensor Location Calibration .

Did the known good TPMS sensors transmit correctly and did the horn sound when the known good TPMS sensors transmitted to the BCM?

Yes	If some of the sensors trained, INSTALL a new TPMS sensor for each sensor that failed to train. REFER to: Tire Pressure Monitoring System (TPMS) Sensor . If all the known good sensors trained, INSTALL new TPMS sensors. REFER to: Tire Pressure Monitoring System (TPMS) Sensor .

GO to C4

C4 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION

Ignition OFF.

Disconnect and inspect all BCM connectors.

Repair:
- corrosion (install new connector or terminals - clean module pins).
- damaged or bent pins - install new terminals/pins.
- pushed-out pins - install new pins as necessary.

Reconnect the BCM connectors. Make sure they seat and latch correctly.

Operate the system and determine if the concern is still present.

Is the concern still present?

Yes

If all the sensors are present, CHECK OASIS for any applicable Technical Service Bulletins (TSBs). If a TSB, GSB, SSM, or FSA. If a service article exists for the concern, DISCONTINUE this test and FOLLOW the service article instructions. If no Technical Service Bulletins (TSBs) address this concern, Refer to BCM Guided Routine Testing .

No	The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.