DTC P0404

DTC P0404  : EGR Valve Circuit Range/Performance Problem

DTC (PGM-FI)

1. Problem verification

   -1. Turn the vehicle to the ON mode.

   -2. Clear the DTC with the HDS.

   -3. Turn the vehicle to the OFF (LOCK) mode.

   -4. Enter the maintenance mode, then start the engine .

   -5. Hold the engine speed at 3000 RPM without load (in P or N) until the radiator fan comes on, then let it idle.

   -6. Do the EGR TEST in the Function Test Menu with the HDS.

   EGR TEST

   Is the result OK?

   YES 

   Intermittent failure, the system is OK at this time. Clean any carbon build-up on the EGR valve with throttle plate cleaner. If the on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the on-board snapshot .

   NO 

   The failure is duplicated. Go to step 2.

2. EGR valve position sensor internal circuit check

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Disconnect the following connector.

   EGR valve 5P connector

   -3. At the EGR valve side, measure the resistance between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	EGR valve 5P connector: disconnected
   Test point 1	EGR valve 5P connector (male terminals) No. 3 (valve side):
   Test point 2	EGR valve 5P connector (male terminals) No. 4 (valve side):

   Courtesy of HONDA, U.S.A., INC.

   Is there 100 kΩ or more?

   YES 

   Replace the EGR valve .

   NO 

   Go to step 3.

3. EGR valve internal circuit check

   -1. At the EGR valve side, measure the resistance between test point 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	EGR valve 5P connector: disconnected
   Test point 1	EGR valve 5P connector (male terminals) No. 2 (valve side):
   Test point 2	EGR valve 5P connector (male terminals) No. 4 (valve side):

   Courtesy of HONDA, U.S.A., INC.

   Is there 100 kΩ or more?

   YES 

   Replace the EGR valve .

   NO 

   Go to step 4.

4. Open wire check (PG2 line)

   -1. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	EGR valve 5P connector: disconnected
   Test point 1	EGR valve 5P connector (female terminals) No. 1:
   Test point 2	Body ground

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   The PG2 wire is OK. Go to step 5.

   NO 

   Repair an open in the PG2 wire between the EGR valve and G102.

5. Shorted wire check (EEGR line)

   -1. Jump the SCS line with the HDS, and wait more than 1 minute.

   -2. Disconnect the following connector.

   PCM connector E (80P)

   -3. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	EGR valve 5P connector: disconnected
   	PCM connector E (80P): disconnected
   Test point 1	PCM connector E (80P) No. 10
   Test point 2	Body ground

   Is there continuity?

   YES 

   Repair a short in the EEGR wire between the PCM (E10) and the EGR valve.

   NO 

   The E EGR wire is not shorted. Go to step 6.

6. Open wire check (EEGR line)

   -1. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	EGR valve 5P connector: disconnected
   	PCM connector E (80P): disconnected
   Test point 1	EGR valve 5P connector (female terminals) No. 5:
   Test point 2	PCM connector E (80P) No. 10

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   The EEGR wire is OK. Go to step 7.

   NO 

   Repair an open in the EEGR wire between the PCM (E10) and the EGR valve.

7. EGR port and passage cleaning

   -1. Remove the EGR valve .

   -2. Clean the intake manifold EGR port with throttle plate cleaner. Also, clean the passage inside the EGR valve with throttle plate cleaner.

   -3. Install the EGR valve .

   -4. Reconnect all connectors.

   -5. Exit the SCS mode with the HDS.

   -6. Turn the vehicle to the ON mode.

   -7. Reset the PCM with the HDS .

   Reset PCM

   -8. Enter the maintenance mode, then start the engine .

   -9. Hold the engine speed at 3000 RPM without load (in P or N) until the radiator fan comes on, then let it idle.

   -10. Do the EGR TEST in the Function Test Menu with the HDS.

   EGR TEST

   Is the result OK?

   YES 

   The failure is not duplicated. The troubleshooting is complete.

   NO 

   Go to step 8.

8. EGR valve check

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Substitute a known-good EGR valve .

   -3. Turn the vehicle to the ON mode.

   -4. Reset the PCM with the HDS .

   Reset PCM

   -5. Enter the maintenance mode, then start the engine .

   -6. Hold the engine speed at 3000 RPM without load (in P or N) until the radiator fan comes on, then let it idle.

   -7. Do the EGR TEST in the Function Test Menu with the HDS.

   EGR TEST

   Is the result OK?

   YES 

   Replace the original EGR valve .

   NO 

   The EGR valve is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM , then recheck. If DTC P0404 goes away and the PCM was substituted, replace the original PCM .