Scania EMD DTC 5849 NOx sensor T115 downstream of the SCR catalytic converter measures too low a value.

EMD EMD control unit · Scania · 2 variants

Code 5849 (decimal). Some diagnostic tools show it in hexadecimal as 16D9.

In short

NOx sensor T115 downstream of the SCR catalytic converter measures too low a value.

Variant 1

Applies to: EMD0

What does Scania EMD fault code 5849 mean?

NOx sensor T115 downstream of the SCR catalytic converter measures too low a value.

What causes Scania DTC 5849?

- The NOx sensor is fitted outside the exhaust flow. - Fault in the NOx sensor. - Urea deposit in the mixing chamber. - Leakage from the V117 reductant doser. - Leakage between the turbocharger and silencer. - Exhaust gas leakage between the reductant doser and silencer. Note: If the NOx sensor is subsequently fitted outside of the exhaust stream the applicable legislation cannot be met.

How does the system react?

The fault affects the engine's nitrous oxide emissions. Depending on the emission class, it will result in torque reduction, speed limitation and a warning indication.

How to fix Scania EMD fault code 5849?

  1. Check that the NOx sensor is correctly fitted.
  2. Run Manual check for leaks in the exhaust system.
  3. Check that the reductant doser is not leaking reductant into the silencer.
  4. Run Leak test for reductant doser.
  5. Visually check whether the mixing chamber for the reductant is blocked or damaged by urea deposits.
  6. Run Visual check of urea deposits.
  7. If there is a blockage in the mixing chamber:
  8. Run Internal cleaning of the silencer and follow the instructions for rectifying urea deposits.
  9. Run Exhaust gas aftertreatment, checking and rectification of urea deposit.
  10. This wizard burns off any urea deposits in the mixing chamber.
  11. If no other faults are found, renew the NOx sensor.
  12. Verification Verify that the fault is rectified by running Exhaust gas aftertreatment, function test SCR > Select test stage > Checking the NOx sensor.
  13. Check that the fault code has been deactivated.
  14. Clear the fault code.

Variant 2

Applies to: EMD1

Detection

NOx sensor T115 downstream of the SCR catalytic converter measures too low a value.

Possible cause

- The NOx sensor is fitted outside the exhaust stream. - Urea deposits in the mixing chamber. - Leakage from reductant doser V117. - Leakage between the turbocharger and the silencer. - Fault in the NOx sensor. - Exhaust gas leakage between the reductant doser and the silencer. Note: If the NOx sensor is subsequently fitted outside of the exhaust stream, the applicable legislation cannot be observed.

System reaction

The fault affects the engine's nitrous oxide emissions. Depending on the emission class, it will result in torque reduction, speed limitation and a warning indication.

How to fix

  1. Check that the NOx sensor is correctly fitted.
  2. Visually check whether the mixing chamber for the reductant is blocked or damaged by reductant stones.
  3. See the instruction in Scania Multi.
  4. If there is a blockage in the mixing chamber: For vehicles equipped with particulate filters: start the wizard Action if there is a urea deposit under "User Functions/Action if there is a fault resulting in illegal levels of exhaust gases" in order to burn off any reductant stones in the mixing chamber.
  5. For vehicles without particle filters the end plate on the silencer should be replaceed or cleaned, if possible.
  6. Check reductant doser V117 for leakage into the silencer.
  7. If no other faults are found, replace the NOx sensor.
  8. Verify that the fault is rectified by running Exhaust gas aftertreatment, function test SCR, select test stage Checking the NOx sensor.
  9. Check that the fault code has been deactivated.
  10. Clear the fault code.
  11. For Scania Engines: Start the engine and run the engine under load.
  12. Check the amount of dosed reductant through the Checking component V117, when the amount is greater than 0: Check via Checking component T115 that the NOx sensor starts within 15 minutes.
  13. Clear the fault code.Check that the NOx sensor is correctly fitted.
  14. Visually check whether the mixing chamber for the reductant contains urea deposits.
  15. Run Visual check of urea deposits.
  16. If there is a deposit in the mixing chamber: Run Manual check for leaks in the exhaust system.
  17. Check that the reductant doser is not leaking reductant into the silencer.
  18. Run Leak test for reductant doser.
  19. Run Internal cleaning of the silencer and follow the instructions for rectifying urea deposits.
  20. Run Exhaust gas aftertreatment, checking and rectification of urea deposit.
  21. This wizard burns off any urea deposits in the mixing chamber.
  22. If no other faults are found, renew the NOx sensor.
  23. Verify that the fault is rectified by running Exhaust gas aftertreatment, function test SCR, select test stage Checking the NOx sensor.
  24. Check that the fault code has been deactivated.
  25. Clear the fault code.Check that the NOx sensor is correctly fitted.
  26. Visually check whether the mixing chamber for the reductant is blocked or damaged by reductant stones.
  27. See the instruction in Scania Multi.
  28. If there is a blockage in the mixing chamber: For vehicles equipped with particulate filters: start the wizard Action if there is a urea deposit under "User Functions/Action if there is a fault resulting in illegal levels of exhaust gases" in order to burn off any reductant stones in the mixing chamber.
  29. For vehicles without particle filters the end plate on the silencer should be replaceed or cleaned, if possible.
  30. Check reductant doser V117 for leakage into the silencer.
  31. If no other faults are found, replace the NOx sensor.
  32. Verify that the fault is rectified by running Exhaust gas aftertreatment, function test SCR, select test stage Checking the NOx sensor.
  33. Check that the fault code has been deactivated.
  34. Clear the fault code.
  35. For Scania Engines: Start the engine and run the engine under load.
  36. Check the amount of dosed reductant through the Checking component V117, when the amount is greater than 0: Check via Checking component T115 that the NOx sensor starts within 15 minutes.
  37. Clear the fault code. | Check that the NOx sensor is correctly fitted.
  38. Visually check whether the mixing chamber for the reductant is blocked or damaged by reductant stones.
  39. See the instruction in Scania Multi.
  40. If there is a blockage in the mixing chamber: For vehicles equipped with particulate filters: start the wizard Action if there is a urea deposit under "User Functions/Action if there is a fault resulting in illegal levels of exhaust gases" in order to burn off any reductant stones in the mixing chamber.
  41. For vehicles without particle filters the end plate on the silencer should be replaceed or cleaned, if possible.
  42. Check reductant doser V117 for leakage into the silencer.
  43. If no other faults are found, replace the NOx sensor.
  44. Verify that the fault is rectified by running Exhaust gas aftertreatment, function test SCR, select test stage Checking the NOx sensor.
  45. Check that the fault code has been deactivated.
  46. Clear the fault code.
  47. For Scania Engines: Start the engine and run the engine under load.
  48. Check the amount of dosed reductant through the Checking component V117, when the amount is greater than 0: Check via Checking component T115 that the NOx sensor starts within 15 minutes.
  49. Clear the fault code. | Check that the NOx sensor is correctly fitted.
  50. Visually check whether the mixing chamber for the reductant contains urea deposits.
  51. Run Visual check of urea deposits.
  52. If there is a deposit in the mixing chamber: Run Manual check for leaks in the exhaust system.
  53. Check that the reductant doser is not leaking reductant into the silencer.
  54. Run Leak test for reductant doser.
  55. Run Internal cleaning of the silencer and follow the instructions for rectifying urea deposits.
  56. Run Exhaust gas aftertreatment, checking and rectification of urea deposit.
  57. This wizard burns off any urea deposits in the mixing chamber.
  58. If no other faults are found, renew the NOx sensor.
  59. Verify that the fault is rectified by running Exhaust gas aftertreatment, function test SCR, select test stage Checking the NOx sensor.
  60. Check that the fault code has been deactivated.
  61. Clear the fault code.

This information is for guidance only. Always follow the manufacturer workshop manual and safety procedures; if in doubt, contact an authorised workshop.

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