## DTC Troubleshooting: P1253 (21-1)

DTC P1253 (21-1): | 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. Check for external damage to the oil pan.

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

4. | Road test the vehicle: Accelerate in MT: 2nd gear (CVT: D position) to an engine speed over 4,000 rpm (min-1). Hold that engine speed for at least 2 seconds. If DTC P1253 is not repeated during the first road test, repeat this test 2 more times. Is DTC P1253 indicated? YES - Go to 5. NO - Intermittent failure, system is OK at this time. Check the oil consumption if oil was added in 2. 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 solenoid valve 2P connector.

7. | Check for resistance between VTEC solenoid valve 2P connector terminals No. 1 and No. 2. Is there 14-30 W? YES - Go to 8. NO - Replace the VTEC solenoid valve.n

8. | Disconnect ECM/PCM connector B (24P).

9. | 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 10.

10. | Connect VTEC solenoid valve 2P connector terminal No. 1 to body ground with a jumper wire.

11. | Check for continuity between ECM/PCM connector terminal B15 and body ground. Is there continuity? YES - Go to 12. NO - Repair open in the wire between the VTEC solenoid valve and the ECM/ PCM (B15).n

12. | Install the special tools as shown.

13. | Reconnect ECM/PCM connector B (24P) and the VTEC solenoid valve connector.

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

15. | 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 16. NO - Inspect the VTEC solenoid valve.n

16. | Turn the ignition switch OFF.

17. | Disconnect the VTEC solenoid valve 2P connector.

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

19. | 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 - Update the ECM/PCM if it does not have the latest software, or 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 - Inspect the VTEC solenoid valve.n