DTC Troubleshooting: P1259 (22-4)

DTC P1259 (22-4):  VTEC System Malfunction

Special Tools Required
Oil Pressure gauge attachment (  07NAJ-P070100)
 

Low pressure gauge (  07406-0070001)
 
Hose oil pressure (  07ZAJ-S5A0200)
 


1.Reset the ECM/PCM.

2.Check the engine oil level, and refill if necessary.

3.Start the engine. Hold the engine at 3,000 rpm (min-1) with no load (in Park or neutral) until the radiator fan comes on.

4.Road test the vehicle:
Accelerate in 1st gear to an engine speed over 4,000 rpm (min-1). Hold that engine speed for at least 2 seconds. If DTC P1259 is not repeated during the first road test, repeat this test 2 more times.

Is DTC P1259 indicated?


YES - Go to 5.


NO - Intermittent failure, system is OK at this time. Check for poor connections or loose wires at the VTEC solenoid valve and at the  ECM/ PCM.n


5.Turn the ignition switch OFF.

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

7.Check for continuity on VTEC oil pressure switch between the VTEC oil pressure switch 2P connector terminals No. 1 and No. 2.

 

Is there continuity?


YES - Go to 8.


NO - Replace the VTEC oil pressure switch.n


8.Turn the ignition switch ON (II).

9.Measure voltage between VTEC oil pressure switch 2P connector terminal No. 1 and body ground.

 

Is there battery voltage?


YES - Go to 15.


NO - Go to 10.

10.Measure voltage between ECM/PCM connector terminal B9 and body ground.

 

Is there battery voltage?


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


NO - Go to 11.


11.Turn the ignition switch OFF.

12.Disconnect the negative cable from the battery.

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

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

 

Is there continuity?


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


NO - Substitute a known-good ECM/PCM and recheck. If symptom/indication goes away, replace the original  ECM/ PCM.n

15.Measure voltage between VTEC oil pressure switch 2P connector terminals No. 1 and No. 2.

 

Is there battery voltage?


YES - Go to 16.


NO - Repair open in the wire between the VTEC oil pressure switch and  G101.n


16.Turn the ignition switch OFF.

17.Disconnect the VTEC solenoid valve 1P connector.

18.Check for resistance between VTEC solenoid valve 2P connector terminals No. 1 and No. 2.

 

Is there 14-30 W?


YES - Go to 19.


NO - Replace the  VTEC solenoid valve.n

19.Remove the VTEC oil pressure switch (A) and install the special tools as shown, then reinstall the VTEC oil pressure switch.

 

20.Reconnect the VTEC solenoid valve 2P connector and VTEC oil pressure switch 2P connector.

21.Connect a tachometer.

22.Start the engine. Hold the engine at 3,000 rpm (min-1) with no load (in Park or neutral) until the radiator fan comes on.

23.Check oil pressure at engine speeds of 1,000 and 2,000 rpm (min-1). Keep measuring time as short as possible because the engine is running with no load (less than 1 minute).

Is pressure below 49 kPa (0.5 kgf/cm2, 7 psi)?


YES - Go to 24.


NO - Inspect the VTEC solenoid valve.n

24.Turn the ignition switch OFF.

25.Disconnect the VTEC solenoid valve 2P connector.

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

27.Start the engine, then connect the battery negative to terminal No. 1 and check oil pressure at an engine speed of 3,000 rpm (min-1).

Is pressure above 390 kPa (4.0 kgf/cm2, 57 psi)?


YES - Go to 28.


NO - Inspect the VTEC solenoid valve.n


28.With the battery terminal still connected to the  VTEC solenoid valve, measure voltage between ECM/PCM connector terminal B9 and body ground.

 

Is there battery voltage above 4,000 rpm (min-1)?


YES - Go to 29.


NO - Replace the VTEC oil pressure switch.n


29.Turn the ignition switch OFF.

30.Disconnect the battery terminal from the VTEC solenoid valve terminal.

31.Reconnect the negative cable to the battery.

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

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

 

Is there continuity?


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


NO - Go to 34.

34.Connect VTEC solenoid valve 2P connector terminal No. 2 to body ground with a jumper wire.

 

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

 

Is there continuity?


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


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