Diagnosis And Testing - Turbocharger Boost Pressure

WARNING: This page is about a different car, the 2011 RAM Pickup and 2011 RAM Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

Low turbocharger boost pressure can cause poor engine performance and driveability concerns. The following procedure will test the turbocharger boost pressure.

Causes of low boost pressure include the following:

Restricted air inlet system
Leak in charge air cooler system
Damaged wastegate command valve O-rings
Restricted/high pressure drop across charge air cooler
Damaged turbocharger compressor wheel housing
Turbocharger wastegate stuck open
Excessive exhaust restriction
Stuck or sticking variable geometry components (6.7L diesel engine)
Stuck or inoperative variable geometry actuator (6.7L diesel engine)

Causes of excessively high boost pressure include:

Turbocharger wastegate stuck closed
Turbocharger wastegate signal line leaking or damaged
Damaged turbocharger actuator O-ring (6.7L Diesel)
Wastegate command valve mechanically stuck in actuated position
Stuck or sticking variable geometry components (6.7L diesel engine)
stuck or inoperative variable geometry actuator (6.7L diesel engine)

Several Diagnostic Trouble Codes (DTCs) can be set that will indicate high or low system boost levels. There is a DTC for circuit faults relating to the electronically controlled wastegate command valve.

Refer to COOLER and HOSES, Charge Air, Diagnosis and Testing, 6.7L for diagnosing of low or high boost pressure due to leaks.

NOTE:

If oil is present on either the inlet or exhaust side of the turbo charger, check the charge air cooler for evidence of oil. Clean charge air cooler of any oil before starting the engine. Failure to do this can result in severe engine damage.