Diagnostic Test

WARNING: This page is about a different variant/trim than selected.

CHECK FOR AN ACTIVE DTC
1. Ignition on, engine not running.
2. With the scan tool, erase DTCs in the PCM.
3. Start the engine and allow the engine to reach normal operating temperature.
4. Monitor the scan tool for at least two minutes.
5. With the scan tool, select View DTCs.
  Is the status Active for this DTC?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT DTC .
CHECK FOR OTHER DTCS
1. Refer to the recorded DTCs.
  Are DTCs P20B9, P20BB, or P20BC active or pending?
  
  Yes
  - Perform the applicable diagnostic procedure(s). Refer to DIAGNOSTIC CODE INDEX .
  No
  - Go To 3
CHECK THE (F343) ASD SUPPLY CIRCUIT, (A914) FUSED B+ CIRCUIT AND THE (Z909) HCU GROUND CIRCUIT FOR A SHORT TO GROUND OR AN OPEN/HIGH RESISTANCE
1. Turn the ignition on, engine off.
2. Measure the voltage across the (F343) ASD Supply circuit and the (Z909) HCU Ground circuit at the DEF HCU harness connector. Then, measure the voltage across the (A914) Fused B+ circuit and the (Z909) HCU Ground circuit at the DEF HCU harness connector.
  Was the difference of either voltage reading greater than 1.0 Volts of battery voltage?
  
  Yes
  - Repair the (F343) ASD Supply circuit or the (A914) Fused B+ circuit for an open or short to ground, or check the (Z909) Ground circuit for an open.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to PCM VERIFICATION TEST .
  No
  - Go To 4
CHECK THE WIRE HARNESS AND CONNECTORS FOR DAMAGED
1. Turn the ignition off.
2. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the DEF HCU and the PCM.
3. Look for any chafed, pierced, pinched, or partially broken wires.
4. Look for broken, bent, pushed out or corroded terminals.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .
  No
  - Go To 5
CHECK THE DIESEL EXHAUST FLUID (DEF) HEATER CONTROL UNIT (HCU) FOR PROPER OPERATION
1. Replace the Diesel Exhaust Fluid (DEF) Heater Control Unit (HCU) in accordance with the service information.
2. Turn the ignition on.
3. With the scan tool, erase PCM DTCs.
4. Start the engine and run it until it reaches operating temperature.
5. Test drive the vehicle under normal operating conditions.
  NOTE:
  During cold ambient temperatures, it may be necessary to test drive the vehicle for an extended period to properly cycle the fail conditions for this DTC.
6. With the scan tool, read PCM DTCs.
  Does the scan tool display this DTC?
  
  Yes
  - Go To 6
  No
  - Test complete.
  - Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .
CHECK RELATED HARNESS CONNECTIONS
1. Disconnect all PCM 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.
  - Check for spread terminals and verify proper terminal tension.
  Repair any conditions that are found.
5. Connect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
6. Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
7. Connect 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. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
10. With the scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL (PCM), REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to PCM VERIFICATION TEST .
  No
  - Repair the poor connections.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to PCM VERIFICATION TEST .