C1665

C1665

Component Location:

General Description
The LFI (Low Frequency Initiator) is located at each vehicle wheel house (FL, FR, RL, RR). High Line systems are fitted with LFI units. An LFI unit mounted in each wheel well to enable the receiver unit to determine the vehicle position of each sensor for which it has a stored ID code. Using a digital bi-directional serial control line to each LFI, the receiver can activate an LFI to send out an LF message and trigger the sensor near its location to respond with an RF transmission. By activating LFI units one at a time, the receiver can automatically locate the vehicle position of each sensor. For fault detection, the LFI will report back its "operating properly" status to the receiver via the control line. The LF communication prolong battery life (through state changes) and determine sensor location (through one-to-one handshaking between LFI and transmitter).

DTC Description
This DTC indicates that there is a short circuit to GND of the initiator supply that runs from the receiver to initiator. The most likely failure is harness / initiator / connector / receiver short circuit.

DTC Detecting Condition:

Schematic Diagram:

Terminal and Connector Inspection
1. 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.
2. Thoroughly check all connectors (and connections) for looseness, bending, corrosion, contamination, deterioration, and/or damage.
3. Has a problem been found?

YES - Repair if necessary and then go to "Verification of Vehicle Repair" procedure.

NO - Go to "Control Circuit Inspection" procedure.

Control Circuit Inspection
1. Engine "OFF".
2. Connect TPMS receiver connector.
3. Engine "ON".
4. Measure waveform between terminal "5" of TPMS receiver harness connector and chassis ground by using a oscilloscope.






5. Is the measured waveform within specifications?

YES
- 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.

NO
- Check for short to power in supply harness.
- Repair if necessary and then go to "Verification of Vehicle Repair" procedure.

Verification of Vehicle Repair
After a repair, it is essential to verify that the fault has been corrected.
1. Connect TPMS exciter or scantool and select "Diagnostic Trouble Codes (DTCs)" mode
2. Using a TPMS exciter or scantool, Clear DTC.
3. Operate the vehicle within DTC Enable conditions in General information.
4. Are any DTCs present?

YES - Go to the applicable troubleshooting procedure.

NO - System performing to specification at this time.