Diagnostic Test

CHECK FOR AN ACTIVE DTC
1. Start the engine and test drive the vehicle to operate the EGR Valve.
2. With the scan tool, read DTCs and record on the repair order.
  Is the DTC active or pending?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK THE (K684) EGR CONTROL 2 CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the EGR Valve harness connector.
3. Disconnect the PCM C2 harness connector.
4. Check for continuity between ground and the (K684) EGR Control 2 circuit at the EGR Valve harness connector.
  Is there continuity between ground and the (K684) EGR Control 2 circuit?
  
  Yes
  - Repair the (K684) EGR Control 2 circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 3
CHECK FOR THE (K684) EGR CONTROL 2 CIRCUIT SHORTED TO THE (K682) EGR CONTROL 1 CIRCUIT
1. Check for continuity between the (K684) EGR Control 2 circuit and the (K682) EGR Control 1 circuit at the EGR Valve harness connector.
  Is there continuity between the (K684) EGR Control 2 circuit and the (K682) EGR Control 1 circuit?
  
  Yes
  - Repair the short between the (K684) EGR Control 2 circuit and the (K682) EGR Control 1 circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 4
EGR VALVE
1. Replace the EGR Valve in accordance with the Service Information. The EGR VALVE REPLACED routine must be performed after replacing or cleaning the EGR Valve to reset the zero learn position. Failure to do so will cause a false failure and the P1404 DTC to set. With the scan tool, perform the EGR VALVE REPLACED routine.
2. Reconnect the EGR Valve harness connector.
3. Reconnect the PCM C2 harness connector.
4. Turn the ignition on.
5. With the scan tool, erase DTCs.
6. Start the engine and test drive the vehicle.
7. With the scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Go To 5
  No
  - Repair is complete.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK RELATED PCM AND COMPONENT CONNECTIONS
1. Perform any Service Bulletins that apply.
2. Disconnect all PCM 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 PCM 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 the Powertrain Control Module in accordance with the Service information. Refer to MODULE, POWERTRAIN CONTROL (PCM), REMOVAL AND INSTALLATION .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  - Test complete.