Compression, Checking: Procedure

WARNING: This page is about a different car, the 2018 Volkswagen Jetta, 2017 Volkswagen Jetta, and 2016 Volkswagen Jetta. However, it is still accessible from the selected car via links, so may be relevant.

Engine oil temperature at least 30 °C (86 °F).
Battery voltage at least 12.5 V.

-- Remove the fuse for the fuel pump control module from the fuse panel. Fuse assignment. Refer to the Appropriate Wiring Diagram.

NOTE:

Removing the fuse interrupts the voltage supply to the fuel pump control module.

-- Start the engine and let it run until it stops.

-- Switch off the ignition.

-- Remove the resonator for the intake air scoop. Refer to INTAKE AIR SCOOP RESONATOR, REMOVING AND INSTALLING .

-- Disconnect the connector -2- and remove the screw -1-.

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Remove the ignition coils with power output stage.

-- Remove the spark plugs using a :3122B .

-- Check the compression using the :VAG1763 . Refer to the Operating information.

-- Have a second technician press the accelerator pedal all the way down and operate the starter at the same time, until the pressure increase is no longer displayed on the tester.

-- Repeat the procedure on each cylinder.

Compression Pressure	Pressure
New	10.0 to 15.0 bar (145.03 to 217.55 psi)
Wear limit	7.0 bar (101.52 psi)
Maximum difference between cylinders	3.0 bar (43.5 psi)

Assembling

Assemble in the reverse order of removal. Note the following:

-- Install spark plugs.

-- Install the ignition coils with power output stages. Refer to IGNITION COILS WITH POWER OUTPUT STAGES, REMOVING AND INSTALLING .

-- If the connectors were disconnected and the engine was started, then malfunctions have been stored in the engine control module DTC memory.

-- Run the function generate readiness code in the Guided Functions . Refer to Vehicle Diagnostic Tester.