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 - ERASE DTCS AND CHECK FOR DTC TO RETURN
WARNING:
On vehicles equipped with the high voltage system, you must thoroughly read and follow all High Voltage Safety procedures. In addition, before performing any diagnostic or service procedure near a high voltage component, you must perform the High Voltage Power Down. Failure to follow these instructions may result in possible serious or fatal injury.

Read the HIGH-VOLTAGE SAFETY PROCEDURES. Refer to HIGH VOLTAGE SAFETY PROCEDURES .

When the HIGH-VOLTAGE POWER-DOWN PROCEDURE is necessary. Refer to VEHICLE HIGH VOLTAGE POWER DOWN .
1. With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
2. For future reference, with the scan tool, run and save a vehicle Scan Report and all related recorded data.
3. With the scan tool, erase all DTCs.
4. Turn the ignition off for a minimum of 10.0 seconds.
5. Turn the ignition on.
6. Using the When Monitored and Set Conditions above and recorded data, operate the vehicle in the conditions that set the DTC.
7. With the scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Go To 2
  No
  - Perform the appropriate INTERMITTENT CONDITION diagnostic procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
ISOLATE AND CHECK THE (H309) WAKE-UP CIRCUIT FOR A SHORT TO GROUND
1. The ignition must be off when checking a circuit for continuity to ground.
2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and every component harness connector containing the circuit being tested. Note: Use the wiring diagram as a guide to follow the path of the circuit.
3. Connect the negative lead of the DVOM to a known good ground.
4. With the positive lead of the DVOM, probe the circuit being tested at the component harness connector and check for continuity between the circuit and ground.
  NOTE:
  There should be no continuity between ground and the circuit being tested.
  
  Is there continuity between ground and the circuit being tested?
  
  Yes
  - Repair the circuit for a short to ground. Use the wiring diagram as a guide to trace the circuit and look for any in-line connectors to help isolate the location of the short.
  - Perform the Electric Vehicle Control Unit (EVCU) VERIFICATION TEST. Refer to ELECTRIC VEHICLE CONTROL UNIT (EVCU) VERIFICATION TEST .
  No
  - Go To 3
ISOLATE AND CHECK THE (H309) WAKE-UP CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. The ignition must be off when checking the continuity of a circuit.
2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and the component harness connector containing the circuit being tested. Note: Use the wiring diagram as a guide to follow the path of the circuit.
3. Before measuring the resistance of any circuit, first measure the resistance between the two leads of the DVOM. Note: The meter leads can add resistance to the measurement value.
4. Connect one lead of the DVOM to the circuit being tested at the component harness connector.
5. Connect the other lead to the circuit being tested at the EVCU connector and measure the resistance of the circuit.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the circuit for an open or high resistance.
  - Perform the Electric Vehicle Control Unit (EVCU) VERIFICATION TEST. Refer to ELECTRIC VEHICLE CONTROL UNIT (EVCU) VERIFICATION TEST .
ISOLATE AND CHECK THE (H309) WAKE-UP CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT AT THE EVCU HARNESS CONNECTOR
1. The ignition must be off when performing a resistance check to find a short between circuits.
2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and every component harness connector containing the circuit being tested. At this time leave all in-line connectors connected. Note: Use the wiring diagram as a guide to follow the path of the circuit.
3. Connect one lead of the DVOM to the circuit being tested at the ECU harness connector.
4. With the other lead of the DVOM probe all other circuits at the ECU harness connector.
  NOTE:
  With the circuit isolated there should be no continuity between the circuit being tested and any other circuit.
  
  Is there continuity between the circuit being tested and any other circuit?
  
  Yes
  - Repair the short between the circuits that have continuity. Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors to help isolate the location of the short.
  - Perform the Electric Vehicle Control Unit (EVCU) VERIFICATION TEST. Refer to ELECTRIC VEHICLE CONTROL UNIT (EVCU) VERIFICATION TEST .
  No
  - Go To 5
CHECK RELATED EVCU AND COMPONENT CONNECTIONS
1. Perform any Service Bulletins that apply.
2. Disconnect all EVCU harness connectors.
3. Disconnect all related in-line harness connections (if equipped).
4. Disconnect the related component harness connectors.
5. 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.
  - Check for spread terminals and verify proper terminal tension.
  Repair any conditions that are found.
6. Reconnect all EVCU harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
7. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
9. With the scan tool, erase DTCs.
10. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
11. With the scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Replace and program the Electric Vehicle Control Unit (EVCU) in accordance with the Service Information. Refer to ELECTRIC VEHICLE CONTROL UNIT (EVCU) .
  - Perform the Electric Vehicle Control Unit (EVCU) VERIFICATION TEST. Refer to ELECTRIC VEHICLE CONTROL UNIT (EVCU) VERIFICATION TEST .
  No
  - The wiring or poor connection problem has been repaired.
  - Perform the Electric Vehicle Control Unit (EVCU) VERIFICATION TEST. Refer to ELECTRIC VEHICLE CONTROL UNIT (EVCU) VERIFICATION TEST .