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, 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 (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 .

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 Function Test 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. If the on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the on-board snapshot .

   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).

   Courtesy 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 Function Test 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 (4.00 kgf/cm 2, 56.9 psi)?

   YES 

   Replace rocker arm oil pressure switch A (Bank 1) .

   NO 

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

5. Shorted wire check (VTMB1 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 E (80P)

   -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 E (80P): disconnected
   Test point 1	PCM connector E (80P) No. 31
   Test point 2	Body ground

   Is there continuity?

   YES 

   Repair a short in the VTMB1 wire between the PCM (E31) and rocker arm oil pressure switch A (Bank 1).

   NO 

   The VTMB1 wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM , then recheck. If DTC P2646 goes away and the PCM was substituted, replace the original PCM .