DTC P0404: EGR Control Circuit Range/Performance Problem

Turn the ignition switch ON (II).
Clear the DTC with the HDS.
Start the engine. Hold the engine speed at 3,000 RPM without load (in Park or neutral) until the radiator fan comes on, then let it idle.
Do the EGR TEST in the INSPECTION MENU with the HDS.
Is the result OK?
1. YES - Intermittent failure, system is OK at this time. Clean any carbon build-up on the EGR valve with throttle plate and induction cleaner.
2. NO - Go to step 5.
Turn the ignition switch OFF.
Disconnect the EGR valve 6P connector.
At the sensor side, measure resistance between EGR valve 6P connector terminals No. 1 and No. 2.

Fig 1: Identifying EGR Valve 6P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there 100 k Ω or more?
1. YES - Go to step 25.
2. NO - Go to step 8.
Measure resistance between EGR valve 6P connector terminals No. 1 and No. 3.

Fig 2: Measuring Resistance Between EGR Valve 6P Connector Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there 100 k Ω or more?
1. YES - Go to step 25.
2. NO - Go to step 9.
Check for continuity between EGR valve 6P connector terminal No. 6 and body ground.

Fig 3: Checking Continuity Between EGR Valve 6P Connector Terminal No. 6 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Go to step 10.
2. NO - Repair open in the wire between the EGR valve and G101, then go to step 26.
Jump the SCS line with the HDS.
Disconnect PCM connector C (44P).
Check for continuity between PCM connector terminal C9 and body ground.

Fig 4: Checking Continuity Between PCM Connector Terminal C9 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Repair short in the wire between the PCM (C9) and the EGR valve, then go to step 26.
2. NO - Go to step 13.
Check for continuity between PCM connector terminal C9 and EGR valve 6P connector terminal No. 4.

Fig 5: Checking Continuity Between PCM Connector Terminal C9 And EGR Valve 6P Connector Terminal
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Go to step 14.
2. NO - Repair open in the wire between the PCM (C9) and the EGR valve, then go to step 26.
Remove the EGR valve (see EGR VALVE REPLACEMENT ).
Clean the intake manifold EGR port with throttle plate and induction cleaner. Also, clean the passage inside the EGR valve with throttle plate and induction cleaner.
Install the EGR valve (see EGR VALVE REPLACEMENT ).
Reconnect the EGR valve 6P connector.
Reconnect PCM connector C (44P).
Turn the ignition switch ON (II).
Reset the PCM with the HDS.
Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
Start the engine. Hold the engine speed at 3,000 RPM without load (in Park or neutral) until the radiator fan comes on, then let it idle.
Do the EGR TEST in the INSPECTION MENU with the HDS.
Is the result OK?
1. YES - Go to step 32.
2. NO - Go to step 24.
Turn the ignition switch OFF.
Replace the EGR valve (see EGR VALVE REPLACEMENT ).
Reconnect all connectors.
Turn the ignition switch ON (II).
Reset the PCM with the HDS.
Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
Start the engine. Hold the engine speed at 3,000 RPM without load (in Park or neutral) until the radiator fan comes on, then let it idle.
Do the EGR TEST in the INSPECTION MENU with the HDS.
Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0404 indicated?
1. YES - Check for poor connections or loose terminals at the EGR valve and the PCM, then go to step 34.
2. NO - Go to step 33.
Monitor the OBD STATUS for DTC P0404 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
1. YES - Troubleshooting is complete. If any other Temporary DTCs or DTCs are indicated in step 32, go to the indicated DTC's troubleshooting
2. NO - If the screen indicates FAILED, check for poor connections or loose terminals at the EGR valve and the PCM, then go to step 1. If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION, go to step 30.
Update the PCM if it does not have the latest software, or substitute a known-good PCM (see PCM UPDATING AND SUBSTITUTION FOR TESTING ).
Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
Do the EGR TEST in the INSPECTION MENU with the HDS.
Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0404 indicated?
1. YES - Check for poor connections or loose terminals at the EGR valve and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step 35. If the PCM was substituted, go to step 1.
2. NO - Go to step 38.
Monitor the OBD STATUS for DTC P0404 in the DTCs MENU with the HDS.
Does the screen indicated PASSED?
1. YES - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM (see PCM REPLACEMENT ). If any other Temporary DTCs or DTCs are indicated in step 37, go to the indicated DTC's troubleshooting
2. NO - If the screen indicates FAILED, check for poor connections or loose terminals at the EGR valve and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step 35 if the PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, go to step 35.