Compression Test - Hybrid

The compression test requires cranking the engine a minimum of 5 compression strokes with the throttle plate in the wide-open position for each cylinder. The engine cranking diagnostic mode must be used to crank the engine and the brake/accelerator pedals must be used to position the throttle plate during the compression test. The engine cranking diagnostic mode is a PCM strategy which is separate from the normal operating strategy. It allows the engine to crank in a similar fashion as a conventional vehicle with the fuel disabled. When in this mode, the PCM commands the TCM to spin the generator, which cranks the engine with the speed between 900 and 1, 200 rpm. The engine will crank as long as the traction battery state of charge stays greater than 35%.

Make sure the oil in the crankcase is of the correct viscosity and at the correct level. Operate the vehicle until the engine is at normal operating temperature.
Using the VCM, access the BCM - HVTB (high voltage traction battery) and monitor the traction battery state of charge PID. If the monitored PID displays the state of charge below 45%, start and idle the engine with full A/C ON. When the traction battery state of charge exceeds 45%, the engine cranking diagnostic mode can be activated.
NOTE: All spark plugs must be removed to check compression. Failure to remove all spark plugs can result in inaccurate test results.

Turn the ignition switch to the OFF position. Then remove all the spark plugs.
Install a compression gauge such as the Quick Disconnect Compression Tester in the No. 1 cylinder.
Press the brake and accelerator pedal fully.
Press the start button to crank the engine or turn the key for vehicles with key start to start the vehicle.
The engine will crank for approximately 3 seconds. Release the accelerator pedal.
Repeat the test on each cylinder, cranking the engine approximately the same number of compression strokes.
Position the key to the OFF position to deactivate the cranking diagnostic mode.
Clear all DTC.