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 INTERMITTENT CONDITION
1. Turn the ignition on.
2. With the scan tool, erase the DTCs.
3. Cycle the ignition from on to off three times.
4. Turn the ignition on and wait 30 seconds.
5. With the scan tool, read the DTCs.
  NOTE:
  If the D508 LIN Bus circuit is shorted to Ground or Battery voltage, this code will appear as Stored and when erased will return as Stored.
  
  Does the scan tool display: B221D-RAIN SENSOR MODULE (RSM) INTERNAL either Active or Stored?
  
  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 .
(D508) LIN BUS CIRCUIT SHORTED TO GROUND

Fig 1: Checking LIN Bus Circuit Shorted To Ground
Courtesy of CHRYSLER GROUP, LLC
1. Turn the ignition off.
2. Disconnect the Rain Sensor harness connector.
3. Measure the resistance between ground and the (D508) LIN Bus circuit in the rain sensor connector.
  Is the resistance below 20, 000 Ohms?
  
  Yes
  - Go To 4.
  No
  - Go To 3.
(D508) LIN BUS CIRCUIT SHORTED TO BATTERY

Fig 2: Checking LIN Bus Circuit For A Short To Battery
Courtesy of CHRYSLER GROUP, LLC
1. Turn the ignition on.
2. Measure the voltage between the (D508) LIN Bus circuit and ground.
  NOTE:
  The voltage should fluctuate between approximately 7.0 and 9.8 volts.
  
  Is the voltage above 10.0 volts?
  
  Yes
  - Go To 5.
  No
  - Replace the Rain Sensor in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
(D508) LIN BUS WIRE SHORTED TO GROUND

Fig 3: Checking LIN Bus Circuit Shorted To Ground
Courtesy of CHRYSLER GROUP, LLC
1. Disconnect the Wireless Control Module (WCM) harness connector.
2. Measure the resistance between ground and the (D508) LIN Bus circuit in the rain sensor connector.
  Is the resistance below 20, 000 Ohms?
  
  Yes
  - Repair the (D508) LIN Bus circuit for a short to ground.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Replace the Wireless Control Module (WCM) in accordance with the Service Information.
  - Perform the WIRELESS CONTROL MODULE (WCM) VERIFICATION TEST. Refer to STANDARD PROCEDURE .
(D508) LIN BUS WIRE SHORTED TO BATTERY

Fig 4: Checking LIN Bus Circuit For A Short To Battery
Courtesy of CHRYSLER GROUP, LLC
1. Turn the ignition off.
2. Disconnect the Wireless Control Module (WCM) harness connector.
3. Turn the ignition on.
4. Measure the voltage between the (D508) LIN Bus circuit and ground.
  Is there any voltage present?
  
  Yes
  - Repair the LIN Bus wire for a short to voltage.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Replace the Wireless Control Module (WCM) in accordance with the Service Information.
  - Perform the WIRELESS CONTROL MODULE (WCM) VERIFICATION TEST. Refer to STANDARD PROCEDURE .