Low Frequency Initiator
The LFI is located at each vehicle wheel house(F/L, F/R, R/R). An LFI unit is mounted in each wheel well of a vehicle to enable the Receiver unit to determine the vehicle position of each WE for which it has a stored ID code. Using a LIN communition line to each LFI, the Receiver can activate an LFI to send out an LF message and trigger the WE sensor near its location to respond with an RF transmission. By activating the LFI units one at a time, the Receiver can automatically locate the vehicle position of each WE. For fault detection, the LFI will report back its “operating properly” status to the Receiver via the LIN communition line.
This DTC indicates that a LIN failure is detected when the LFI does not respond to communication check request when triggered for the 3 time. LIN failure leads to a localization failure. Therefore, this failure is verified only when localization failed. In the event of ECU over or under voltage the LFI is not powered thus DTC is not stored.
Item | Detecting Condition | Possible cause |
DTC strategy | ● Check pulse and voltage | ● Open / Short to ground in FL LFI LIN circuit ● Open in FL LFI LIN ground circuit ● Short to battery in LFI LIN circuit |
Enable conditions | ● IGN ON (not over and under voltage detected) ● On start of driving after parking for more than 19 min. | |
Threshold value | ● LFI 3 times successively triggered and LFI never respond. | |
Mil On conditon | ● Within 1 minute after IGN ON |
Set up ＇GDS＇ with ＇GDS TPMS＇.
Select the "CURRENT DATA" function of "TPMS" system.
Monitor the parameters related to ＇Rear Right/ Left LFI＇ on the GDS.
Specification : When the vehicle is driving over 25 km/h and acceleration is more than 5g,
＇LFI No Response Pulse＇ is ＇NO＇.
＇LFI Fail Pulse＇ is ＇NO＇.
＇LFI Pass Pulse＇ is ＇YES＇.
Fig.1) Detect "PASS" pulse from LFI(normal)
Are parameters normal?
▶ Fault is intermittent. It has been repaired and TPMS receiver module memory is not cleared yet.
▶ Go to "Verification of vehicle Repair" procedure.
▶ Go to "Inspection/Repair" procedure.
Many malfunctions in the electrical system are caused by poor harness and terminal condition.
Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
Thoroughly check all connectors (and connections) for looseness, bending, corrosion, contamination, deterioration, and/or damage.
Has a problem been found?
▶ Repair if necessary and then go to "Verification of Vehicle Repair" procedure.
▶ Go to "Power Circuit Inspection" procedure.
Ignition "OFF"
Disconnect Rear Right/Left initiator connector.
Ignition "ON", Engine "OFF".
Measure voltage between power terminal of Rear Right/Left initiator harness connector and chassis ground.
Specification : Approx. 12V
Is the voltage measured within specifications?
▶ Go to "Signal Circuit Inspection" procedure.
▶ Repair open in power circuit between Rear Right/Left initiator harness connector chassis ground and then go to "Verification of Vehicle Repair" procedure.
Ignition "OFF"
Disconnect Rear Right/Left initiator connector and TPMS receiver connector.
Measure resistance between LIN terminal of Rear Right/Left initiator harness connector and LIN terminal of TPMS receiver harness connector.
Specification : Approx. 0 Ω
Is the resistance measured within specifications?
▶ Go to "Check Short to battery" procedure.
▶ Repair open in LIN circuit between Rear Right/Left initiator harness connector and TPMS receiver harness connector and then go to "Verification of Vehicle Repair" procedure.
Ignition "OFF"
Disconnect Rear Right/Left initiator connector and TPMS receiver connector.
Measure resistance between power terminal and LIN terminal of Rear Right/Left initiator harness connector.
Specification : ∞
Is the resistance measured within specifications?
▶ Go to "5." as follows.
▶ Repair short to battery in LIN circuit between Rear Right/Left initiator harness connector and TPMS receiver harness connector and then go to "Verification of Vehicle Repair" procedure.
Ignition "ON".
Measure voltage between LIN terminal of Rear Right/Left initiator harness connector and chassis ground.
Specification : Approx. 0 V
Is the voltage measured within specifications?
▶ Go to "Check short to ground" procedure.
▶ Repair short to battery in LIN circuit between Rear Right/Left initiator harness connector and TPMS receiver harness connector and then go to "Verification of Vehicle Repair" procedure.
Ignition "OFF"
Disconnect Rear Right/Left initiator connector and TPMS receiver connector.
Measure resistance between LIN terminal and ground terminal of Rear Right/Left initiator harness connector.
Specification : ∞
Is the resistance measured within specifications?
▶ Go to "Ground Circuit Inspection" procedure.
▶ Repair short to ground in LIN circuit between Rear Right/Left initiator harness connector and TPMS receiver harness connector and then go to "Verification of Vehicle Repair" procedure.
Ignition "OFF"
Disconnect Rear Right/Left initiator connector.
Measure resistance between ground terminal of Rear Right/Left initiator harness connector and chassis ground.
Specification : Approx. 0 Ω
Is the resistance measured within specifications?
▶ Substitute with a known-good TPMS receiver and check for proper operation.
▶ If the problem is corrected, replace TPMS receiver and then go to "Verification of Vehicle Repair" procedure.
▶ Repair open in ground circuit between Rear Right/Left initiator harness connector chassis ground and then go to "Verification of Vehicle Repair" procedure.
After a repair, it is essential to verify that the fault has been corrected.
Connect TPMS exciter or scantool and select "Diagnostic Trouble Codes(DTCs)" mode
Using a TPMS exciter or scantool, Clear DTC.
Operate the vehicle within DTC Enable conditions in General information.
Are any DTCs present ?
▶ Go to the applicable troubleshooting procedure.
▶ System performing to specification at this time.
