DTC P0406

DTC P0406  : EGR Valve Position Sensor Circuit High Voltage

NOTE:  Before you troubleshoot, review the general troubleshooting information .

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)	More than 4.88	V

   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 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 .

2. Determine possible failure area (EGR valve position sensor, others)

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

   -2. Disconnect the following connector.

   EGR 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 5P connector: disconnected
   Test point 1	EGR valve 5P connector No. 2
   Test point 2	EGR valve 5P connector No. 3

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

   Is there about 5.0 V?

   YES 

   Replace the EGR valve .

   NO 

   Go to step 3.

3. Open wire check (SG2 line)

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

   -2. Jump the SCS line with the HDS.

   -3. Disconnect the following connector.

   PCM connector B (51P)

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

   Test condition	Vehicle OFF (LOCK) mode
   	EGR 5P connector: disconnected
   	PCM connector B (51P): disconnected
   Test point 1	PCM connector B (51P) No. 5
   Test point 2	EGR valve 5P connector No. 3

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

   Is there continuity?

   YES 

   The SG2 wire is OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM , then recheck. If DTC P0406 goes away and the PCM was updated, troubleshooting is complete. If DTC P0406 goes away and the PCM was substituted, replace the original PCM .

   NO 

   Repair an open in the SG2 wire between the PCM (B5) and the EGR valve.