LOW PRESSURE AND EGR COOLER BLOCKAGES

In this article, Opus IVS details its support of a customer with a 2L diesel ingenium engine with low pressure and an exhaust valve cooler blockage

Opus IVS explains that its IVS 360 is an “invaluable diagnostic support resource uniquely designed to empower technicians to repair vehicles with confidence.”
Through its dedicated team of OEM-Trained Master Technicians, the Opus IVS team provides brand-specific diagnostic support to technicians and workshop owners all over the world.
It says customers can quickly and easily request support from the IVS 360 team directly from their DrivePro device.
Following is an example of a customer support request and guidance provided from the IVS 360 Land Rover OEM-Trained Master Technicians.

The above picture shows a blocked LP EGR cooler filter LR126126 covered in soot particles.

Vehicle Type Affected: Land Rover/Jaguars (and any vehicle fitted with the 2.0 diesel ingenium engine).

Model types: Including but not limited to: Range Rover Evoque, Discovery Sport, Land Rover Defender, Range Rover, Range Rover Sport.

Vehicle Fault: Vehicle in restricted performance and DTC P049B-00.

Fault codes: P049B-00 EGR “B” Flow Insufficient Detected – No sub type information. Also, other low pressure EGR related DTCs.

Low Pressure EGR (LPEGR) explained:
Opus IVS explains that the LP EGR system is used on EU5 and EU6 market vehicles only.
The LP system takes exhaust gases from the exit of the Diesel Particulate Filter (DPF) system and mixes it with the fresh air intake into the turbocharger. The gases are transported from the DPF outlet to the LP EGR cooler via a pipe. The LP cooler has no bypass mode, and so only cools.
There is a simple mesh filter fitted before the gasses reach the outlet of the cooler that prevents larger particles of soot etc from entering the turbo charger system. The mesh filter is a non-serviceable component. The cooled gases are then directed through the LP EGR valve, via a butterfly flap.
The valve consists of a tube between the fresh air duct and the turbocharger, with the butterfly valve covering the EGR inlet, in the center bottom of the EGR valve. The butterfly valve opens into the fresh air stream, promoting both thorough mixing before the gas enters the turbocharger, and also provides ‘suction’ to drive the LP EGR gas through the system.

DPF filter internal collapse/failure.

Possible Causes:
• Excessive undetected soot in the DPF
• Charged air induction system leak
• Low pressure EGR cooler blocked/filter blocked
• Low pressure EGR valve mechanical integrity
• Low pressure EGR differential pressure sensor mechanical integrity
• Connector is disconnected, connector pin is backed out, connector pin corrosion
• Vehicle is fitted with Two EGR valves, a LP and HP unit. One is DPF side to turbo the other is exhaust manifold to intake manifold.

Blurred outer edging shows output side of the DPF, clearly with soot present, which indicates a DPF problem.

Repair:

  1. Using a HP smoke detector, visually inspect the air intake system for leaks. Repair any that are found.
  2. If there are no signs of soot particles, this is not the cause of the customer’s concern.
  3. Remove low pressure EGR cooler housing lid and visually inspect for soot particles.
  4. Is the cooler blocked? Opus IVS has seen filters internally block as per the image shown to the top right. This would require a new filter set (LR126126) and cleaning of the EGR/Throttle body and the Low pressure EGR cooler.
  5. Look at low pressure EGR pipe on the nearside – is it blocked?
  6. Look for signs of sooting around the clamp.
  7. Is there black soot around the tail pipe?
  8. Loosen the SCR assembly, look up into the cooler and check for excessive levels of soot.
  9. Check to see if the DPF/SCR canister is cracked internally.
  10. Using the JLR process, change the LP EGR and cooler.
  11. Change cooler pressure sensor and SCR/DPF unit. The pressure sensor is bolted to the intake side of the engine, it looks like a DPF pressure sensor, one goes to the cooler pack and the longer pipe goes to cooling unit this measures the pressure either side of the unit.
  12. If the cooler also shows signs of being excessively blocked, then the cooler may need replacing as well.
  13. The DPF may also need inspecting for cracks that can draw in air from the outside causing excessive sooting.
  14. After the repair, reconfigure existing PCM with latest software using a dealer tool.
Replacement Kit.

Replacement Kit
Where possible, visually inspect downstream of the DPF and LPEGR exhaust pipe for soot using a bore scope or visually check with the exhaust separated and look for soot content in the exhaust system.
If soot is not visible downstream of the DPF and the LPEGR exhaust pipe, then do not replace the DPF. 
If soot is visible downstream of the DPF and the LPEGR exhaust pipe, replace the DPF.

Inside view showing the DPF internal collapse/break down.

Also be sure to visually check for any potential signs of cracking or leaks. Leaks can be evident from rusting water marks or even carbon build up at the exterior seams.

For information on IVS 360 support, visit www.opusivs.com or contact sales-au@opusivs.com or 03 8561 7600.