Compression Check: Testing and Inspection

Engine Compression Inspection

NOTE: After the inspection, you must reset the PCM. Otherwise, the PCM will continue to stop the fuel injectors from operating.

1. Warm up the engine to normal operating temperature (cooling fan comes on).

2. Turn the ignition switch to LOCK (0).

3. Connect the HDS to the DLC.

4. Turn the ignition switch to ON (II).

5. Make sure the HDS communicates with the vehicle and the PCM. If it does not communicate, troubleshoot the DLC circuit Testing and Inspection.

6. Select ALL INJECTORS STOP in the PGM-FI INSPECTION menu with the HDS.

7. Turn the ignition switch to LOCK (0).

8. Remove the four intake side ignition coils and the spark plugs Service and Repair.

9. Attach the compression gauge to a spark plug hole.

NOTE: Use a compression gauge with a connecting length (between the edge and the flange) of less than 23 mm (0.91 in).





10. Turn the IMA battery module switch OFF.

11. Step on the accelerator pedal to open the throttle fully, then crank the engine with the starter motor, and measure the compression.





12. Measure the compression on the remaining cylinders.





13. If the compression is not within specifications, perform a cylinder leak down test to determine the problem area. Then check the following items, and remeasure the compression.

- Incorrect valve clearance
- Confirmation of cam timing
- Damaged or worn cam lobes
- Looseness exhaust side spark plug
- Damaged or worn valves and seats
- Damaged cylinder head gasket
- Damaged or worn piston rings
- Damaged or worn piston and cylinder bore

14. Remove the compression gauge from the spark plug hole.

15. Install the four intake side spark plugs and the ignition coils Service and Repair.

16. Select PCM reset in the PGM-FI INSPECTION menu to cancel ALL INJECTORS STOP with the HDS.

17. Do the PCM idle learn procedure PCM Idle Learn Procedure.

18. Do the start clutch pressure control calibration procedures Programming and Relearning.

19. Turn the IMA battery module switch ON.

20. Clear any IMA DTCs that may have been set while doing this inspection procedure.

21. If the 12 V battery is discharged, its cables have been disconnected, or the MCM (motor control module) has been reset, the IMA battery level gauge (BAT) does not display the state-of-charge (SOC) when the engine is first started. To display the level in the level gauge (BAT), start the engine, and hold it between 3,500 rpm and 4,000 rpm without load (in P or N) until the level in the level gauge (BAT) displays at least three segments.