U1114
U1114 - Lost Communication with Left Front Tire Pressure Trigger Module
For a complete wiring diagram, refer to.
Theory of Operation
The tire pressure monitoring transponder is used to automatically learn the location of each wheel TPM sensor on the vehicle. The module is controlled and activated in sequence by the wireless ignition node over a LIN bus. When activated, the module will generate a 125 KHz signal of sufficient field strength to trigger the TPM transponder and force a low frequency RF transmission from the TPM sensor.
• When Monitored: Continuously with the ignition ON and the IOD fuse installed.
• Set Condition: If the WIN fails to receive bus messages from the TPM transponder for two consecutive counts of TPM transponder not responding to a communication check.
Test Step 1 - Verify DTC is Active
• Ensure the IOD fuse is installed and battery voltage is between 10 and 16 volts before proceeding.
• Ignition ON, engine not running.
• With the scan tool, read and record DTCs.
• With the scan tool, erase DTCs.
• Cycle the ignition switch.
• With the scan tool, read DTCs.
Does this DTC reset?
Yes
• Go to Test Step 2
No
• Perform the Stored Lost Communication procedure. Refer to => Non-DTC Based Diagnostics.
• Perform Body Verification Test. Refer to => Non-DTC Based Diagnostics. Body Interior
Test Step 2 - Fused Ignition Switch Output (Run) Circuit Open or High Resistance
• Turn the ignition OFF.
• Disconnect the TPM transponder harness connector.
• Ignition on, engine not running.
• Using a 12 volt test lamp connected to ground, check the fused ignition switch output (run) circuit.
• The test lamp should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.
Does the test lamp illuminate brightly?
Yes
• Go to Test Step 3
No
• Repair the circuit for an open circuit or high resistance.
• Perform TPM Verification Test. Refer to => Non-DTC Based Diagnostics. Tire Pressure Monitor Verification Test
Test Step 3 - Ground Circuits Open or High Resistance
• Using a 12 volt test lamp connected to 12 volts, check each of the ground circuits.
• The test lamp should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.
Does the test lamp illuminate brightly?
Yes
• Go to Test Step 4
No
• Repair the ground circuits for an open circuit or high resistance.
• Perform TPM Verification Test. Refer to => Non-DTC Based Diagnostics. Tire Pressure Monitor Verification Test
Test Step 4 - COM-LIN Tire Pressure Monitor LAN Circuit Short to Voltage
• Turn the ignition OFF.
• Disconnect the WIN harness connector.
• Ignition ON, engine not running.
• Measure the voltage of the COM-LIN tire pressure monitor LAN circuit.
Is there any voltage present?
Yes
• Repair the COM-LIN tire pressure monitor LAN circuit for a short to voltage.
• Perform TPM Verification Test. Refer to => Non-DTC Based Diagnostics. Tire Pressure Monitor Verification Test
No
• Go to Test Step 5
Test Step 5 - COM-LIN Tire Pressure Monitor LAN Circuit Short to Ground
• Turn the ignition OFF.
• Measure the resistance between ground and the COM-LIN tire pressure monitor LAN circuit.
Is the resistance less than 5.0 ohms?
Yes
• Repair the COM-LIN tire pressure monitor LAN circuit for a short to ground.
• Perform TPM Verification Test. Refer to => Non-DTC Based Diagnostics. Tire Pressure Monitor Verification Test
No
• Go to Test Step 6
Test Step 6 - COM-LIN Tire Pressure Monitor LAN Circuit Open or High Resistance
• Use a jumper wire with one end connected to ground and the other to the COM-LIN tire pressure monitor LAN circuit in the left front tire pressure transponder harness connector.
• Using a 12 Volt test lamp connected to battery voltage, probe the COM-LIN tire pressure monitor LAN circuit in the WIN harness connector.
• The test lamp should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.
Does the test lamp illuminate brightly?
Yes
• Go to Test Step 7
No
• Repair the circuit for an open circuit or high resistance.
• Perform TPM Verification Test. Refer to => Non-DTC Based Diagnostics. Tire Pressure Monitor Verification Test
Test Step 7 - COM-LIN Tire Pressure Monitor LAN Circuit Open
• Turn the ignition OFF.
• Measure the resistance of the COM-LIN tire pressure monitor LAN circuit.
Is the resistance less than 5 Ohms?
Yes
• Go to Test Step 8
No
• Repair the open circuit.
• Perform TPM Verification Test. Refer to => Non-DTC Based Diagnostics. Tire Pressure Monitor Verification Test
Test Step 8 - Power and Ground Circuit Open
• Ignition ON, engine not running.
• With a voltmeter measure the voltage between the power and ground circuit at the TPM transponder.
Is the voltage at least the same as battery voltage?
Yes
• Go to Test Step 9
No
• Repair the open circuit.
• Perform TPM Verification Test. Refer to => Non-DTC Based Diagnostics. Tire Pressure Monitor Verification Test
Test Step 9 - Check for Additional TPM Transponder Communication Related DTCs
• With the scan tool, select network view and select advanced.
Is there more than one module with active DTCs logged against the WIN?
Yes
• Replace the wireless ignition node.
• Perform TPM Verification Test. Refer to => Non-DTC Based Diagnostics. Tire Pressure Monitor Verification Test
No
• Replace the TPM transponder.
• Perform TPM Verification Test. Refer to => Non-DTC Based Diagnostics. Tire Pressure Monitor Verification Test