LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Chevrolet >> 2012 >> Sonic L4-1.8L >> Repair and Diagnosis >> Powertrain Management >> Tune-up and Engine Performance Checks >> Compression Check >> Testing and Inspection
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Compression Check: Testing and Inspection




Engine Compression Test

Removal Procedure

1. Remove the throttle body. Refer to Throttle Body Assembly Replacement Removal and Replacement.

2. Remove the spark plugs. Refer to Spark Plug Replacement Service and Repair.

3. Remove the relay holder cover.

4. Remove the fuel pump relay.

Measurement Procedure

Check Compression for all cylinders:

Note:
Engine revs at least 300/min.

1. Start the engine (approx. 4 seconds).

2. Compare the compression values.

Maximum pressure differential 100 kPa (14.5 psi)

Installation Procedure

1. Install the fuel pump relay.

* Place into the socket.

* Ensure the plug contacts are sound.

2. Install the relay carrier cover.

3. Install the spark plugs. Refer to Spark Plug Replacement Service and Repair.

4. Install the throttle body. Refer to Throttle Body Assembly Replacement Removal and Replacement.