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DTC P2646

DTC P2646  : Rocker Arm Oil Pressure Switch A (Bank 1) Circuit Low Voltage

Special Tools Required 

Pressure Gauge Adapter 07NAJ-P07010A 

A/T Low Pressure Gauge w/Panel 07406-0070301 

A/T Pressure Test Hose 07AAJ-PY4A100 

A/T Pressure Adapter 07MAJ-PY40120 

Oil Pressure Hose 07ZAJ-S5AA200 

NOTE:
  • Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information .
  • If DTC P2648 and/or P2649 are stored at the same time as DTC P2646, troubleshoot those DTCs first, then recheck for DTC P2646.
DTC Description Confirmed DTC Pending DTC Freeze Frame
P2646 Rocker Arm Oil Pressure Switch A (Bank 1) Circuit Low Voltage      

DTC (PGM-FI)

  1. Oil level check

    -1. Check the engine oil level .

    Is the level OK?

    YES 

    Go to step 2.

    NO 

    Adjust the engine oil to the proper level , then do the repair verification.

  2. Problem verification

    -1. Turn the vehicle to the ON mode.

    -2. Clear the DTC with the HDS.

    -3. Select the VTEC+VCM TEST in the INSPECTION MENU with the HDS, then select the VEB VTEC TEST with the HDS.

    VEB VTEC TEST

    Does the HDS indicate Normal?

    YES 

    Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at rocker arm oil pressure switch A (Bank 1) and the PCM.

    NO 

    The failure is duplicated. Go to step 3.

  3. Determine possible failure area (VTMB1 line, Others)

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

    -2. Disconnect the following connector.

    Rocker arm oil pressure switch A (Bank 1) 2P connector

    -3. Turn the vehicle to the ON mode.

    -4. Check the parameter(s) below with the HDS.

    Signal Current conditions
    Values Unit
    ROCKER ARM OIL PRESSURE SWITCH A (BANK 1)    

    Is ON indicated?

    YES 

    Go to step 5.

    NO 

    Go to step 4.

  4. VTEC system oil pressure check

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

    -2. Remove rocker arm oil pressure switch A (Bank 1) (A), and attach the special tools as shown, then attach rocker arm oil pressure switch A (Bank 1) to the oil pressure gauge adapter (B).

    GHH345284Courtesy of HONDA, U.S.A., INC.

    -3. Reconnect the following connector.

    Rocker arm oil pressure switch A (Bank 1) 2P connector

    -4. Start the engine.

    -5. Select the VTEC+VCM TEST in the INSPECTION MENU with the HDS, then select the VEB VTEC TEST with the HDS.

    VEB VTEC TEST

    Check the oil pressure.

    Does the oil pressure increase to 392 kPa (4.0 kgf/cm2, 56.9 psi)?

    YES 

    Replace rocker arm oil pressure switch A (Bank 1) , then do the repair verification.

    NO 

    Inspect the VTEC system. If it is OK, replace the rear rocker arm oil control valve , then do the repair verification.

  5. Shorted wire check (VTMB1 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 C (51P)

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

    Test condition Vehicle OFF (LOCK) mode
      Rocker arm oil pressure switch A (Bank 1) 2P connector: disconnected
      PCM connector C (51P): disconnected
    Test circuit VTMB1
    Test point 1 PCM connector C (51P) No. 22 (PUR)
    Test point 2 Body ground
    GHH345285Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Repair a short in the VTMB1 wire between rocker arm oil pressure switch A (Bank 1) and the PCM (C22), then do the repair verification.

    NO 

    The VTMB1 wire is OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM , then do the repair verification.

  6. Repair verification

    -1. Reconnect all connectors.

    -2. Exit the SCS mode with the HDS.

    -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. Select the VTEC+VCM TEST in the INSPECTION MENU with the HDS, then select the VEB VTEC TEST with the HDS.

    VEB VTEC TEST

    Check for Pending or Confirmed DTCs with the HDS.

    DTC Description Confirmed DTC Pending DTC Freeze Frame
    P2646 Rocker Arm Oil Pressure Switch A (Bank 1) Circuit Low Voltage      

    DTC (PGM-FI)

    Is DTC P2646 indicated?

    YES 

    Check for poor connections or loose terminals at rocker arm oil pressure switch A (Bank 1) and the PCM. If the PCM was updated, substitute a known-good PCM , then recheck. If the PCM was substituted, go to step 1.

    NO 

    Troubleshooting is complete. If the PCM was substituted, replace the original PCM . If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.

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