DTC P0405 (18-21 6-Speed A/T, 2018 9-Speed A/T)

DTC P0405  : EGR Valve Position Sensor Circuit Low Voltage

NOTE:  Before you troubleshoot, review the general troubleshooting information - Refer to: How to Troubleshoot the Fuel and Emissions Systems .

DTC (PGM-FI)

1. Problem verification

   - 1. Turn the vehicle to the ON mode.

   - 2. Check the parameter(s) below with the HDS.

   Signal	Threshold		Current conditions
   	Values	Unit	Values	Unit
   EGR valve position sensor (EGR VLS)	Less than 0.31	V

   Data List

   Do the current condition(s) match the threshold?

   YES 

   The failure is duplicated. Go to step 2.

   NO 

   Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the EGR valve and the PCM. If the on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the on-board snapshot - Refer to: How to Troubleshoot the Fuel and Emissions Systems .

2. Open wire check (VCC1 line)

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

   - 2. Disconnect the following connector.

   EGR valve 5P connector

   - 3. Turn the vehicle to the ON mode.

   - 4. Measure the voltage between test points 1 and 2.

   Test condition	Vehicle ON mode
   	EGR valve 5P connector: disconnected
   Test point 1	EGR valve 5P connector (female terminals) No. 2:
   Test point 2	EGR valve 5P connector (female terminals) No. 3:

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

   Is there about 5.0 V?

   YES 

   The VCC1 wire is OK. Go to step 3.

   NO 

   Repair an open in the VCC1 wire between the PCM (C32) and the EGR valve.

3. Shorted wire check (EGRL line)

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

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

   - 3. Disconnect the following connector.

   PCM connector C (51P)

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

   Test condition	Vehicle OFF (LOCK) mode
   	EGR valve 5P connector: disconnected
   	PCM connector C (51P): disconnected
   Test point 1	EGR valve 5P connector (female terminals) No. 4:
   Test point 2	Body ground

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

   Is there continuity?

   YES 

   Repair a short in the EGRL wire between the PCM (C46) and the EGR valve.

   NO 

   The EGRL wire is not shorted. Go to step 4.

4. Open wire check (EGRL line)

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

   Test condition	Vehicle OFF (LOCK) mode
   	EGR valve 5P connector: disconnected
   	PCM connector C (51P): disconnected
   Test point 1	EGR valve 5P connector (female terminals) No. 4:
   Test point 2	PCM connector C (51P) No. 46 - Refer to: PCM Connector for Inputs and Outputs(6-Speed A/T) (2016 2017 2018 2019 2020), or PCM Connector for Inputs and Outputs (9-Speed A/T) (2016 2017 2018)

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

   Is there continuity?

   YES 

   The EGRL wire is OK. Go to step 5.

   NO 

   Repair an open in the EGRL wire between the PCM (C46) and the EGR valve.

5. PCM internal circuit check

   - 1. Connect terminals A and B with a jumper wire.

   Terminal A	EGR valve 5P connector (female terminals) No. 2:
   Terminal B	EGR valve 5P connector (female terminals) No. 4:

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

   - 2. Reconnect PCM connector C (51P).

   - 3. Exit the SCS mode with the HDS.

   - 4. Turn the vehicle to the ON mode.

   - 5. Check the parameter(s) below with the HDS.

   Signal	Threshold		Current conditions
   	Values	Unit	Values	Unit
   EGR valve position sensor (EGR VLS)	Less than 0.31	V

   Data List

   Do the current condition(s) match the threshold?

   YES 

   Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM - Refer to: PCM Removal and Installation (6-Speed A/T), ('16-'18 9-Speed A/T) , then recheck. If DTC P0405 goes away and the PCM was substituted, replace the original PCM - Refer to: PCM Removal and Installation (6-Speed A/T), ('16-'18 9-Speed A/T) .

   NO 

   The PCM internal circuit is OK. Replace the EGR valve .