Diagnostic Test

WARNING: This page is about a different car, the 2024 RAM ProMaster EV. However, it is still accessible from the selected car via links, so may be relevant.

READ AND RECORD DTCS AND ENVIRONMENTAL DATA
NOTE: CLEARING THE DTC AFTER A REPAIR - Perform after a wiring repair or component replacement:
To erase the DTC from the Body Control Module (BCM), the BCM must detect an ignition ON/OFF/ON cycle, making sure the Power Accessory Delay (PAD) is deactivated (driver door opened) after the ignition transitions to the OFF position, along with the normal operation of the system that is associated with this DTC.
1. Turn the ignition on.
2. With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
3. With the scan tool, run a vehicle Scan Report, or record the Environmental Data related to the DTCs.
4. With the scan tool, read Body Control Module (BCM) DTCs.
  Is the DTC Active?
  
  Yes
  - Go To Next Step.
  No
  - Perform the appropriate INTERMITTENT CONDITION diagnostic procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
CHECK THE (B20) BRAKE FLUID LEVEL SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the Brake Fluid Level Switch harness connector.
3. Disconnect the related BCM harness connector.
4. Turn the ignition on.
5. Measure the voltage on the Brake Fluid Level Switch Signal circuit at the Brake Fluid Level Switch harness connector.
  Is there any voltage present?
  
  Yes
  - Repair the short to voltage in the Brake Fluid Level Signal circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To Next Step.
CHECK THE (B20) BRAKE FLUID LEVEL SIGNAL CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Measure the resistance of the Brake Fluid Level Signal circuit between the Brake Fluid Level Switch harness connector and the related BCM harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To Next Step.
  No
  - Repair the open in the Brake Fluid Level Signal circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE (Z909) BRAKE FLUID LEVEL SENSOR GROUND CIRCUIT FOR AN OPEN
NOTE:
The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
1. Using a 12-volt test light connected to 12-volts, check the Ground circuit at the Brake Fluid Level Switch harness connector.
  Does the test light illuminate brightly?
  
  Yes
  - Go To Next Step.
  No
  - Repair the open in the Ground circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE BCM FOR CORRECT OPERATION
1. Turn the ignition off.
2. Connect the related BCM harness connector.
3. Connect a jumper wire between ground and the Brake Fluid Level Signal circuit at the Brake Fluid Level Switch harness connector.
4. Turn the ignition on.
5. With the scan tool, read the Brake Fluid Level.
  Does the Brake Fluid Level display Low Level?
  
  Yes
  - Replace the Brake Fluid Level Switch in accordance with the Service Information. Refer to BRAKE FLUID LEVEL SWITCH .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To Next Step.
CHECK RELATED HARNESS CONNECTIONS
1. Disconnect all BCM harness connectors.
2. Disconnect all related in-line harness connections (if equipped).
3. Disconnect the related component harness connectors.
4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
  - Proper connector installation.
  - Damaged connector locks.
  - Corrosion.
  - Other signs of water intrusion.
  - Weather seal damage (if equipped).
  - Bent terminals.
  - Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
  - Terminals that have been pushed back into the connector cavity.
  - Perform a terminal drag test on each connector terminal to verify proper terminal tension.
  Repair any conditions that are found.
5. Reconnect all BCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
6. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
7. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. With the scan tool, erase DTCs.
9. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
10. With the scan tool, read BCM DTCs.
  Did the DTC return?
  
  Yes
  - Replace the Body Control Module (BCM) in accordance with the Service Information. Refer to MODULE, BODY CONTROL (BCM), REMOVAL AND INSTALLATION .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  - Test complete.