DTC Troubleshooting: P2646 (22-3)

DTC P2646 (22-3):  VTEC Oil pressure Switch Circuit Low Voltage

Special Tools Required
Oil pressure gauge adapter (  07NAJ-P070100)
 

Low pressure gauge (  07406-0070002)
 
Hose, oil pressure (  07ZAJ-S5A0200)
 


1.Turn the ignition switch OFF.

2.Check the engine oil level.

Is the level OK?


YES - Go to 3.


NO - Adjust the engine oil to the proper level.n


3.Turn the ignition switch ON (II).

4.Reset the ECM/PCM.

5.Start the engine. Hold the engine speed at 3,000 rpm (min-1) without load (in Park or neutral) until the radiator fan comes on, then let it idle.

6.Test-drive under following conditions:
Accelerate in M/T, A/T: 2nd gear to engine speed over 5,000 rpm (min-1). Hold the speed for all least 2 seconds.

Is DTC P2646 Indicated?


YES - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the VTEC oil pressure switch, the VTEC solenoid valve and the ECM/PCM.n


NO - Go to 7.

7.Turn the ignition switch OFF.

8.Remove the VTEC oil pressure switch (A) and install the special tools as shown, then install the VTEC oil pressure switch (A) to the oil pressure gauge adapter.

NOTE: Install the part in the reverse order of removal with a new O-ring.

 

9.Disconnect the VTEC solenoid valve 2P connector.

10.Start the engine. Hold the engine speed at 3,000 rpm (min-1) without load (in Park or neutral) until the radiator fan comes on, then let it idle.

11.Attach the battery positive terminal to VTEC solenoid valve 2P connector terminal No. 2.

12.Start the engine, then connect the battery negative terminal to VTEC solenoid valve 2P connector terminal No. 1, and check the oil pressure at an engine speed of 3,000 rpm (min-1).

Is the oil pressure above 390 kPa (4.0 kgf·cm2, 57 psi)?


YES - Go to 13.


NO - Inspect the VTEC solenoid valve.n

13.Disconnect the VTEC oil pressure switch 2P connector.

14.At VTEC oil pressure switch side, check for continuity between VTEC oil pressure switch terminals No. 1 and No. 2 in the condition of 13.

 

Is there continuity?


YES - Replace the  VTEC oil pressure switch.n


NO - go to 15.


15.Turn the ignition switch OFF.

16.Disconnect the battery terminals from the VTEC solenoid valve terminal connector.

17.Disconnect ECM/PCM connector B (24P).

18.Check for continuity between ECM/PCM connector terminal B9 and body ground.

 

Is there continuity?


YES - Repair short in the wire between the ECM/PCM (B9) and the VTEC oil pressure switch.n


NO - Go to 19.


19.Check for continuity between VTEC solenoid valve 2P connector terminal No. 1 and body ground.

 

Is there continuity?


YES - Go to 20.


NO - Repair open in the wire between the VTEC solenoid valve and G101.n

20.Check for continuity between ECM/PCM connector terminal B15 and body ground.

 

Is there continuity?


YES - Repair short in the wire between the ECM/PCM (B15) and the VTEC solenoid valve.n


NO - Go to 21.


21.Connect the VTEC solenoid valve 2P connector terminal No. 2 and body ground with a jumper wire.

 

22.Check for continuity between ECM/PCM connector terminal B15 and body ground.

 

Is there continuity?


YES - Substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original  ECM/ PCM.n


NO - Repair open in the wire between the ECM/PCM (B15) and the VTEC solenoid valve.n