Diagnostic Test

WARNING: This page is about a different car, the 2012 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.

TEST FOR AN INTERMITTENT CONDITION
1. With the scan tool, record and erase the WCM DTCs.
2. Cycle the ignition switch from on to off three times then back to on.
3. Start the engine and run for two minutes.
4. With the scan tool, read the active WCM DTCs.
  Does the scan tool display: U0231-LOST COMMUNICATION WITH RAIN SENSING MODULE as active?
  
  Yes
  - Go To 2.
  No
  - Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals and poor pin fit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
(F306) FUSED IGNITION SWITCH OUTPUT OPEN

Fig 1: Measuring Voltage Between Fused Ignition Switch Output Circuit And Ground At Rain Sensor Harness Connector
Courtesy of CHRYSLER GROUP, LLC

NOTE:
Be sure the battery is fully charged before proceeding.
1. Turn the ignition off.
2. Disconnect the Rain Sensor harness connector.
3. Turn the ignition on.
4. Measure the voltage between the (F306) Fused Ignition Switch Output circuit and ground in the Rain Sensor harness connector.
  Is the voltage above 12.0 volts?
  
  Yes
  - Go To 3.
  No
  - Repair the (F306) Fused Ignition Switch Output circuit for an open.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
(Z908) GROUND CIRCUIT OPEN

Fig 2: Checking Ground Circuit Terminal At Rain Sensor Connector For An Open
Courtesy of CHRYSLER GROUP, LLC
1. Using the a 12 volt test light connected to 12 volts, check the (Z919/Z920) Ground circuit.
  NOTE:
  The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
  
  Does the test light illuminate brightly?
  
  Yes
  - Go To 4.
  No
  - Repair the (Z919/Z920) Ground circuit for an open.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE VOLTAGE OF THE (D508) LlN BUS CIRCUIT

Fig 3: Measuring Voltage Between LIN Bus Circuit And Ground At Rain Sensor Connector
Courtesy of CHRYSLER GROUP, LLC
1. Measure the voltage between the (D508) LIN Bus circuit and ground in the Rain Sensor connector.
  Is the voltage above 7.0 volts?
  
  Yes
  - Replace the Rain Sensor in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 5.
(D508) LlN BUS CIRCUIT OPEN

Fig 4: Checking LlN Bus Circuit Between WCM Harness Connector And Rain Sensor Harness Connector For An Open
Courtesy of CHRYSLER GROUP, LLC
1. Turn the ignition off.
2. Disconnect the Wireless Control Module (WCM) harness connector.
3. Measure the resistance of the (D508) LIN Bus circuit between the WCM harness connector and the Rain Sensor harness connector.
  Is the resistance below 2.0 Ohms?
  
  Yes
  - Replace the Wireless Control Module in accordance with the Service Information.
  - Perform the WIRELESS CONTROL MODULE (WCM) VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Repair the (D508) LIN Bus circuit for an open.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .