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Home › Jeep › 2020 › Grand Cherokee Trackhawk › Repair and Diagnosis › Engine Mechanical › Exhaust System › Catalyst, Selective Catalytic Reduction (SCR) › Removal

Catalyst, Selective Catalytic Reduction (SCR): Removal

WARNING:

If torches are used when servicing the exhaust system, do not allow any flame near the fuel lines or the fuel tank. Failure to follow these instructions may result in possible serious or fatal injury.

  1. Disconnect and isolate the negative battery cable.
  2. Raise and support the vehicle. Refer to HOISTING, STANDARD PROCEDURE .
  3. If equipped, remove the skid plates.
  4. Disconnect the front exhaust temperature sensors wire harness connector.
    GC0157430Courtesy of CHRYSLER GROUP, LLC
  5. Disconnect the Diesel Exhaust Fluid (DEF) injector wire harness connector (3).
  6. Disconnect the DEF fluid supply line (1). Refer to the appropriate service information .
    GC0172164Courtesy of CHRYSLER GROUP, LLC
  7. Remove the fasteners (1) and the heat shield (2).
    GC0157421Courtesy of CHRYSLER GROUP, LLC
  8. Remove the nuts (2) and NOx sensor 1/2 module cover (1).
    GC0157435Courtesy of CHRYSLER GROUP, LLC
    NOTE:

    DO NOT  try to disconnect wire harness connector (3) from NOx sensor module (1).

  9. Disconnect the NOx sensor wire harness connector (2).
    GC0158422Courtesy of CHRYSLER GROUP, LLC
  10. Remove the nuts (1) and the module mounting bracket (2).
    GC0158426Courtesy of CHRYSLER GROUP, LLC
    NOTE:

    DO NOT  try to disconnect wire harness connector (3) from Particulate Matter (PM) sensor module (1).

  11. Disconnect the PM sensor wire harness connector (1).
    GC0158412Courtesy of CHRYSLER GROUP, LLC
  12. Remove the tailpipe assembly. Refer to TAILPIPE, EXHAUST, REMOVAL .
  13. Remove the SCR from the isolators.
  14. Remove the nuts (8) and the SCR (10).
  15. Remove and discard the flange gasket (7).
    GC0157423Courtesy of CHRYSLER GROUP, LLC
  16. If necessary, using a six sided crow foot to remove the PM sensor (1) from the Selective Catalyst Reduction (SCR).
  17. If the PM sensor fails to loosen use a torque wrench set to 160 N.m (118 ft. lbs.) and loosen the PM sensor (1).
    NOTE:

    DO NOT  use a torch as a heat source.

  18. If the PM sensor (1) is still not loose after applying 160 N.m (118 ft. lbs.) then use a heat gun to heat the PM sensor boss for 1 minute at 450° C (842° F).
  19. If necessary, using a six sided crow foot to remove the NOx sensor 1/2 (2) with module.
  20. If the NOx sensor (2) fails to loosen use a torque wrench set to 160 N.m (118 ft. lbs.) and loosen the NOx sensor (2).
    NOTE:

    DO NOT  use a torch as a heat source.

  21. If the NOx sensor (2) is still not loose after applying 160 N.m (118 ft. lbs.) then use a heat gun to heat the NOx sensor boss for 1 minute at 450° C (842° F).
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