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. Start the engine. Hold the engine speed at 3, 000 rpm without load (in P or N) until the radiator fan comes on, then let it idle.

   - 4. Do the EGR TEST 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 freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot.

   NO 

   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 5P connector

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

   Test condition	Vehicle OFF (LOCK) mode
   	EGR 5P connector: disconnected
   Test circuit	EGRL, SG1
   Test point 1	EGR valve 5P connector No. 3 (EGR valve side)
   Test point 2	EGR valve 5P connector No. 4 (EGR 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 5P connector: disconnected
   Test circuit	EGRL, VCC1
   Test point 1	EGR valve 5P connector No. 2 (EGR valve side)

   Test point 2

   EGR valve 5P connector No. 4 (EGR 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 (E-EGR PG/PG line)

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

   Test condition	Vehicle OFF (LOCK) mode
   	EGR 5P connector: disconnected
   Test circuit	E-EGR PG
   Test point 1	EGR valve 5P connector No. 1 (BLK)
   Test point 2	Body ground

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

   Is there continuity?

   YES 

   The E-EGR PG/PG wire is OK. Go to step 5.

   NO 

   Repair an open in the E-EGR PG/PG wire between the EGR valve and G101.

5. Shorted wire check (E EGR line)

   -1. Jump the SCS line with the HDS.

   - 2. Disconnect the following connector.

   PCM connector C (51P) - Refer to: How to Troubleshoot the Brake Booster Pressure Monitoring System (2016 2017 2018 2019 2020), or How to Troubleshoot the Fuel and Emissions Systems(With Auto Idle Stop System) (2016), or How to Troubleshoot the Fuel and Emissions Systems, or How to Troubleshoot the A/T System (2014 2015)

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

   Test condition	Vehicle OFF (LOCK) mode
   	EGR 5P connector: disconnected
   	PCM connector C (51P): disconnected
   Test circuit	E EGR
   Test point 1	PCM connector C (51P) No. 13 (PUR)
   Test point 2	Body ground

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

   Is there continuity?

   YES 

   Repair a short in the E EGR wire between the PCM (C13) and the EGR valve.

   NO 

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

6. Open wire check (E EGR line)

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

   Test condition	Vehicle OFF (LOCK) mode
   	EGR 5P connector: disconnected
   	PCM connector C (51P): disconnected
   Test circuit	E EGR
   Test point 1	EGR valve 5P connector No. 5 (PUR)
   Test point 2	PCM connector C (51P) No. 13 (PUR)

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

   Is there continuity?

   YES 

   The E EGR wire is OK. Go to step 7.

   NO 

   Repair an open in the E EGR wire between the PCM (C13) and the EGR valve.

7. EGR port and passage check

   -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. Turn the vehicle to the ON mode.

   - 6. Reset the PCM with the HDS.

   Reset PCM

   - 7. Do the PCM idle learn procedure.

   - 8. Do the EGR TEST with the HDS.

   EGR TEST

   Is the result OK?

   YES 

   Troubleshooting is complete.

   NO 

   Go to step 8.

8. EGR valve check (substitution)

   -1. Substitute a known-good EGR valve.

   - 2. Reconnect the following connector.

   EGR valve 5P connector

   - 3. Turn the vehicle to the ON mode.

   - 4. Reset the PCM with the HDS.

   Reset PCM

   - 5. Do the PCM idle learn procedure.

   - 6. Do the EGR TEST with the HDS.

   EGR TEST

   Is the result OK?

   YES 

   Replace the original EGR valve .

   NO 

   The EGR valve is OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM - Refer to: PCM Removal and Installation (2014 2015), or PCM Removal and Installation (2016) .