Diesel Engine - Turbocharger/EGR/Air Cooler Diagnostics
NUMBER: 11-004-06GROUP: Exhaust
DATE: September 2, 2006
THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN 11-003-05, DATED NOVEMBER 10, 2005, WHICH SHOULD BE REMOVED FROM YOUR FILES. ALL REVISIONS ARE HIGHLIGHTED WITH **ASTERISKS** AND INCLUDE A REVISED DISCUSSION AND ADDITIONAL DIAGNOSTIC PROCEDURES.
SUBJECT:
Turbocharger, Charge Air Cooler, and Exhaust Gas Recirculation Systems Diagnosis on 0M647 Engines
MODELS:
2004 - 2006 (VA) Sprinter
SPECIAL TOOLS/EQUIPMENT REQUIRED:
DISCUSSION:
The turbocharger, charge air cooler and exhaust gas recirculation systems operate with one another and must be tested as a complete system. It is important that all components of the air intake system be thoroughly tested any time a symptom is present for one of these components.
It is typical to notice a small amount of engine oil in the air intake system. This comes from crankcase ventilation and may weep out of hose connections that are not clamped properly. This does not mean that the turbocharger requires replacement.
If DTC's or the performance of the vehicle lead to the determination that the boost pressure and/or mass air flow values are out of range, the systems listed below should be inspected. If a DIG for the inlet or intake air temperature has been stored, refer to service bulletin 18-020-05.
NOTE:
A continuous air leak may result in an intermittent symptom. The ECM monitors the sensor readings continuously but only sets a DTC or reduces the engine torque when these readings are outside of the tolerances, which may occur under certain driving conditions.
Inspect the following:
^ **Low turbocharger boost pressure and low engine performance can be caused by leaks in the charge air cooler or it's plumbing. The below procedure outlines how to check for leaks in the charge air cooler system. (A smoke machine does not create enough pressure to find a leak in the air intake system).**
^ Turbo Resonator: Inspect the resonator (muffler, connected to the turbocharger) for air leaks at the seam between the two shells.
^ **Exhaust Gas Recirculation (EGR) valve: A sticking EGR valve influences the mass air flow causing implausibility with MAF, which displays one or more DTC's. Don't replace the EGR valve if no DTC's are present. Use the below EGR valve Diagnostic Procedure to determine if replacement is required.**
^ Mass Air Flow Sensor (MAF): The mass air flow, measured and provided by the MAF is critical for calculations performed by the ECM and may result in several DIG's related to the air intake system if not accurate.
^ Boost Pressure Sensor: Make sure that the correct part with number 51 17545AA (Mercedes Benz part number printed on sensor: A 004 1538428) or superseding part number is installed. The Boost Pressure Sensor for an 0M612 engine would fit mechanically on an 0M647 engine but will result in poor performance.
^ Turbocharger: See Turbocharger Diagnostic Procedure. Consider that an operating turbocharger creates a flow sound, which is normal and does not require replacement. Other sounds like whistling are potentially caused by the resonator or improper line connections.
**CHARGE AIR COOLER DIAGNOSTIC PROCEDURE:
1. Loosen clamp and remove turbocharger to air inlet duct rubber sleeve from air cleaner housing.
2. Insert Special Tool 8442 Adapter into the rubber sleeve. Tighten existing clamp to 8 N.m (72 in. lbs.).
3. Separate the breather hose at the breather heater and block off.
4. Remove the oil level indicator and block off tube.
CAUTION:
Do not apply more then 138 kpa (20 psi) air pressure to the charge air cooler system, sever damage to the charge air cooler system may occur.
5. Connect a regulated air supply to the air fitting on Special Tool 8442 Adapter. Set the air pressure to approximately 0.3 bar (5 psi).
6. Using soapy water check the air inlet ducts, rubber sleeves, charge air cooler and intake manifold for leaks.**
**EGR VALVE DIAGNOSTIC PROCEDURE:
1. Use the actuator test in DRBIII(R) to move the EGR valve at idle speed. The MAF value should alternate between 500 to 600 mg/strk at 5% ratio (almost closed) and 200 to 300 mglstrk at 95% ratio (almost opened) when the "EGR Positioner" is being actuated by DRBIII(R).
NOTE:
DTC's P1403-016 / P1403-032 and P2527-001 / P2527-002 may have been set due to short-term over voltage or under voltage in the on-board electrical system. DTC's P1403-004 / 1403-008 and P2527-004 / P2527-008 may have been set due to short-term dirt particles in the EGR valve.
CAUTION:
Be sure the service and parking brakes are applied before performing the next step!
2. Erase DTC's and warm up the vehicle for approximately 10 minutes. While stationary, place the shift lever in the Drive ("D") position with both the service and the parking brake applied. Run the engine for approximately 3 minutes. Place the shift lever in the Neutral ("N") position and over a period of approximately 1 minute, periodically apply full throttle for approximately 0.5 seconds at approximately 1500 to 2000 rpm.
3. These test steps produce high pressure differentials at the EGR valve with simultaneous, rapid valve position changes. If no DTC's are set, it can be assumed that the EGR valve is electrically and mechanically OK. It is not necessary to replace the EGR valve.**
TURBOCHARGER DIAGNOSTIC PROCEDURE:
1. Visually inspect all the blades of the turbocharger compressor and turbine wheel for damage which may have been caused by foreign particles. For example if the air filter was improperly installed or an incorrect air filter was installed.
NOTE:
The correct air filter element for 2004 - 2006 Sprinter does not have a glued on foam pad.
2. Start the engine and let it run at idle speed. Perform the actuator test using the DRBIII(R). The connecting rod of the actuator should move back and forth when the "Boost Pressure Sol" is being actuated by DRBIII(R) in short intervals. Also note that the values for both MAF and Boost Pressure should alternate slightly if both sensors work properly.
CAUTION:
Do NOT try to move the actuator mechanism by pushing or pulling the connecting rod. There is a worm gear attached to the actuator mechanism, which doesn't allow any movement from its output side.
3. If the actuator mechanism doesn't move at all check power and ground supply of the actuator.
4. **If the actuator mechanism moves erratically or doesn't move at all even though the electrical connection has been verified inspect the pivot of the actuator rod connecting to the turbine lever. Check if corrosion is blocking the movement. If necessary, remove the pivot clip, clean all pivot components from corrosion and apply a high temperature grease (such as MOPAR 05127533AA or equivalent). Reassemble the pivot and redo the actuator test with DRBIII to verify smooth movement.**
5. **If the actuator mechanism still doesn't move after performing the above tests the turbocharger is defective and must be replaced as an entire assembly.**
NOTE:
Never replace the actuator only. The adjustment of the actuator mechanism is set at the factory with special equipment, and is critical for proper operation.
POLICY:
Information Only
Disclaimer:
This bulletin is supplied as technical information only and is not an authorization for repair.