DTC P2646 (19-21 9-Speed A/T)
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 - Refer to: How to Troubleshoot the Fuel and Emissions Systems .
- 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 |
|---|---|---|
| P2646 Rocker Arm Oil Pressure Switch A (Bank 1) Circuit Low Voltage |
DTC (PGM-FI)
- Oil level check
- 1. Check the engine oil level.
Is the level OK?
YES
Go to step 2.
NO
- 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.
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 .
NO
The failure is duplicated. Go to step 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.
- 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).
- 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 (4.00 kgf/cm 2, 56.9 psi)?
YES
Replace rocker arm oil pressure switch A (Bank 1) - Refer to: Rocker Arm Oil Pressure Switch A (Bank 1) and Rocker Arm Oil Pressure Switch B (Bank 1) Removal and Installation .
NO
Inspect the VTEC system. If it is OK, replace the rear rocker arm oil control valve - Refer to: Rear Rocker Arm Oil Control Valve Removal and Installation .
- 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 - Refer to:
PCM Connector for Inputs and Outputs (9-Speed A/T) (2019 2020 2021) .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. - Refer to: PCM Removal and Installation (9-Speed A/T) (2019 2020 2021)
If DTC P2646 goes away and the PCM was substituted, replace the original PCM - Refer to: PCM Removal and Installation (9-Speed A/T) (2019 2020 2021) .