DTC Troubleshooting: P0404 (12)
  1. Check for continuity between ECM connector terminal B2 and EGR valve 5P connector terminal No. 1.
Is there continuity?
YES -
Go to Step 14 .
NO -
Repair open in the wire between the ECM (B2) and the EGR valve, then go to Step 25 .
  1. Remove the EGR valve.
  1. Clean the intake manifold EGR port, and the EGR pipe with throttle plate and induction cleaner. Also, clean the passage inside the EGR valve with throttle plate and induction cleaner.
  1. Install the EGR valve.
  1. Reconnect all connectors.
  1. Turn the ignition switch to ON (II).
  1. Reset the ECM with the HDS.
  1. Do the ECM idle learn procedure.
  1. Start the engine. Hold the engine speed at 3,000 rpm (min −1 ) without load (in neutral) until the radiator fan comes on, then let it idle.
  1. Do the EGR TEST in the INSPECTION MENU with the HDS.
Is the result OK?
YES -
Go to Step 31 .
NO -
Go to Step 23 .
  1. Turn the ignition switch to LOCK (0).
  1. Replace the EGR valve.
  1. Reconnect all connectors.
  1. Turn the ignition switch to ON (II).
  1. Reset the ECM with the HDS.
  1. Do the ECM idle learn procedure.
  1. Start the engine. Hold the engine speed at 3,000 rpm (min −1 ) without load (in neutral) until the radiator fan comes on, then let it idle.
  1. Do the EGR TEST in the INSPECTION MENU with the HDS.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0404 indicated?
YES -
Check for poor connections or loose terminals at the EGR valve and the ECM, then go to Step 1 . If the connections and terminals are OK, go to Step 33 .
NO -
Go to Step 32 .
  1. Monitor the OBD STATUS for DTC P0404 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in Step 31 , go to the indicated DTC's troubleshooting.■
NO -
If the screen indicates FAILED, check for poor connections or loose terminals at the EGR valve and the ECM, then go to Step 1 . If the screen indicates EXECUTING, keep testing until a result comes on. If the screen indicates OUT OF CONDITION, go to Step 29 .
  1. Update the ECM if it does not have the latest software, or substitute a known-good ECM.
  1. Do the EGR TEST in the INSPECTION MENU with the HDS.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0404 indicated?
YES -
Check for poor connections or loose terminals at the EGR valve and the ECM. If the ECM was updated, substitute a known-good ECM, then go to Step 34 . If the ECM was substituted, go to Step 1 .
NO -
Go to Step 36 .
  1. Monitor the OBD STATUS for DTC P0404 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM. If any other Temporary DTCs or DTCs were indicated in Step 35 , go to the indicated DTC's troubleshooting.■
NO -
If the screen indicates FAILED, check for poor connections or loose terminals at the EGR valve and the ECM. If the ECM was updated, substitute a known-good ECM, then go to Step 34 . If the ECM was substituted, go to Step 1 . If the screen indicates EXECUTING, keep testing until a result comes on. If the screen indicates OUT OF CONDITION, go to Step 34 .