Scania EMS DTC 1025 EGR content

EMS Engine Management System · Scania · 4 variants

Code 1025 (decimal). Some diagnostic tools show it in hexadecimal as 0401.

In short

The amount of exhaust gas recirculation requested is lower than expected.

Variant 1: Exhaust gas recirculation 1, mass flow lower than requested

Applies to: EMS10

What does Scania EMS fault code 1025 mean?

The amount of exhaust gas recirculation requested is lower than expected.

What causes Scania DTC 1025?

- The exhaust gas recirculation valve is stuck in the closed position. - Mechanical fault in the exhaust gas recirculation. - Leakage in the exhaust gas recirculation. - The variable geometry turbocharger is stuck in the open position or has speed limitation. - Mass flow sensor fault. - Fault in exhaust gas pressure sensor in the exhaust manifold. - Fault in charge air pressure sensor. - Fault in air temperature sensor. - Fault in the exhaust gas pressure sensor.

What are the symptoms?

The mass flow sensor measurements are based on standard values.

How to fix Scania EMS fault code 1025?

  1. Check the exhaust gas recirculation valve.
  2. Check for mechanical faults in the exhaust gas recirculation.
  3. Check for leaks in the exhaust gas recirculation.
  4. Check the variable geometry turbocharger valve.
  5. Check the mass flow sensor.
  6. Check the exhaust gas pressure sensor in the exhaust manifold.
  7. Check charge air pressure sensor.
  8. Check the air temperature sensor.
  9. Check the exhaust gas pressure sensor.
  10. Vehicles with Euro 5 and Euro 6 emission standards:
  11. After the repair is complete, run the wizard Checking the EGR system for devalidation of fault codes.
  12. Delete the fault codes for NOx monitoring if the performance test could not be completed.

Variant 2

Applies to: EMS S6

Detection

The amount of EGR gases returned is too low, the amount of EGR gases cannot be increased to the required level.

Possible cause

The fault can be due to any of the following: - The damper in the EGR valve cannot be opened. This may be because the damper is jammed, or the control cylinder pressure is insufficient, or because there is internal leakage in the control cylinder. - The proportional valve may be faulty. - The damper in the venturi insert may be stuck in the open position. - Leakage in the recirculation of EGR gases. - The mass flow sensor may be indicating too high a value, resulting in the engine control unit concluding that the engine is receiving too low an amount of EGR gases.

System reaction

The engine control unit switches off the EGR system and calibration of the mass flow sensor is switched off.

How to fix

  1. Check the damper in the EGR valve, the control cylinder and the proportional valve by activating the components with Scania Diagnos.
  2. Check the key in the venturi.
  3. Check for leaks in the EGR system.
  4. Check the mass flow sensor.

Variant 3

Applies to: EMS S7

Detection

Too small a volume of exhaust gases is being recirculated. The desired amount of EGR cannot be reached, or the measurement of the amount of EGR is not reliable.

Possible cause

- The EGR valve is stuck. - Leakage in the EGR circuit or in the engine intake system. - The EGR cooler is blocked. - The turbocharger nozzle ring has stuck. - Turbocharger electric motor M30 is defective. - Mass flow sensor T126 indicates an incorrect value. - Charge air pressure sensor T122 indicates an incorrect value. - Charge air temperature sensor T121 indicates an incorrect value. - Exhaust gas pressure sensor T125 indicates an incorrect value.

System reaction

The fault affects the engine's nitrous oxide emissions. Depending on the emission class, this may result in torque reduction, speed limitation or a warning indication. Applies only to vehicles with Euro 5: The fault code cannot be deleted when it is active.

How to fix

  1. Rectify other fault codes related to the EGR circuit first.
  2. Then check: The EGR valve via valve block V107.
  3. Potential leakage in the EGR circuit or in the engine intake system.
  4. Run EMS > E 44 > S7 > Check > Leak testing the EGR circuit.
  5. That the EGR cooler is intact and not clogged.
  6. The variable geometry turbocharger nozzle ring and electric motor.
  7. Run EMS > E 44 > S7 > Check > Condition test on the variable geometry turbocharger.
  8. Mass flow sensor T126.
  9. Charge air pressure sensor T122.
  10. Charge air temperature sensor T121.
  11. Exhaust gas pressure sensor T125.
  12. When the fault code is inactive, the high exhaust emissions warning lamp will go out.
  13. Note: You may need to carry out a default setting of the EGR circuit.
  14. Run the wizard EMS > E44 > S7 > Calibration > Default setting and calibration of the EGR circuit.
  15. When the actions have been carried out, always check that the fault code has disappeared.
  16. Run the wizard EMS > E 44 > S7 > Check > Checking the EGR circuit to verify that the fault has been rectified.
  17. Drain the EGR cooler if the operating time since the fault code was generated exceeds 10 hours.
  18. The reason for this is that there is a risk that condensed water has formed in the air-cooled EGR cooler while the EGR circuit was switched off.
  19. Drain the EGR cooler according to the instructions in the Workshop Manual > 01-65 EGR system > Air-cooled EGR cooler.

Variant 4

Applies to: EMS S8

Detection

Too small a volume of exhaust gases is being recirculated. The desired amount of EGR cannot be reached, or the measurement of the amount of EGR is not reliable.

Possible cause

- The EGR valve is stuck. - Leakage in the EGR circuit or in the engine intake system. - The EGR cooler is blocked. - The turbocharger nozzle ring has stuck. - Turbocharger electric motor M30 is defective. - Mass flow sensor T126 indicates an incorrect value. - Charge air pressure sensor T122 indicates an incorrect value. - Charge air temperature sensor T121 indicates an incorrect value. - Exhaust gas pressure sensor T125 indicates an incorrect value.

System reaction

The fault affects the engine's nitrous oxide emissions. Depending on the emission class, this may result in torque reduction, speed limitation or a warning indication. Applies only to vehicles with Euro 5: The fault code cannot be deleted when it is active.

How to fix

  1. Rectify other fault codes related to the EGR circuit first.
  2. Then check: The EGR valve via valve block V107.
  3. Potential leakage in the EGR circuit or in the engine intake system.
  4. Run EMS > E 44 > S8 > Check > Leak testing the EGR circuit.
  5. That the EGR cooler is intact and not clogged.
  6. The variable geometry turbocharger nozzle ring and electric motor.
  7. Run EMS > E 44 > S8 > Check > Condition test on the variable geometry turbocharger.
  8. Mass flow sensor T126.
  9. Charge air pressure sensor T122.
  10. Charge air temperature sensor T121.
  11. Exhaust gas pressure sensor T125.
  12. When the fault code is inactive, the high exhaust emissions warning lamp will go out.
  13. You may need to carry out a default setting of the EGR circuit.
  14. Run the wizard EMS > E44 > S8 > Calibration > Default setting and calibration of the EGR circuit.
  15. When the actions have been carried out, always check that the fault code has disappeared.
  16. Run the wizard EMS > E 44 > S8 > Check > Check the EGR circuit to verify that the fault has been rectified.
  17. Applies only to vehicles with Euro 5: If the operating time since the fault code was generated exceeds 10 hours, drain the EGR cooler.
  18. The reason for this is that there is a risk that condensed water has formed in the air-cooled EGR cooler while the EGR circuit was switched off.
  19. Drain the EGR cooler according to the instructions in the Workshop Manual > 01-65 EGR system > Air-cooled EGR cooler.
  20. Rectify other fault codes related to the EGR circuit first.
  21. Then check: Actuator for EGR valve M28.
  22. Potential leakage in the EGR circuit or in the engine intake system.
  23. Run Functions > Check > Emission control > EGR system > EGR circuit leak test.
  24. That the EGR cooler is intact and not clogged.
  25. If the EGR cooler is clogged, the EGR cleaner will clean the radiator according to instructions in the Service Manual > 01-65 EGR circuit > Liquid-cooled EGR cooler > Cleaning of EGR cooler, 9- and 13-litre engine.
  26. The variable geometry turbocharger nozzle ring and electric motor.
  27. Run EMS > E 44 > S8 > Check > Condition test on the variable geometry turbocharger.
  28. Mass flow sensor T126.
  29. Charge air pressure sensor T122.
  30. Charge air temperature sensor T121.
  31. Exhaust gas pressure sensor T125.
  32. When the fault code is inactive, the high exhaust emissions warning lamp will go out.
  33. You may need to carry out a default setting of the EGR circuit.
  34. Run the wizard EMS > E44 > S8 > Calibration > Default setting and calibration of the EGR circuit.
  35. When the actions have been carried out, always check that the fault code has disappeared.
  36. Run the wizard EMS > E 44 > S8 > Check > Check the EGR circuit to verify that the fault has been rectified.
  37. Applies only to vehicles with Euro 5: If the operating time since the fault code was generated exceeds 10 hours, drain the EGR cooler.
  38. The reason for this is that there is a risk that condensed water has formed in the air-cooled EGR cooler while the EGR circuit was switched off.
  39. Drain the EGR cooler according to the instructions in the Workshop Manual > 01-65 EGR system > Air-cooled EGR cooler. | Rectify other fault codes related to the EGR circuit first.
  40. Then check: The EGR valve via valve block V107.
  41. Potential leakage in the EGR circuit or in the engine intake system.
  42. Run EMS > E 44 > S8 > Check > Leak testing the EGR circuit.
  43. That the EGR cooler is intact and not clogged.
  44. The variable geometry turbocharger nozzle ring and electric motor.
  45. Run EMS > E 44 > S8 > Check > Condition test on the variable geometry turbocharger.
  46. Mass flow sensor T126.
  47. Charge air pressure sensor T122.
  48. Charge air temperature sensor T121.
  49. Exhaust gas pressure sensor T125.
  50. When the fault code is inactive, the high exhaust emissions warning light will go out.
  51. You may need to carry out a default setting of the EGR circuit.
  52. Run the wizard EMS > E44 > S8 > Calibration > Default setting and calibration of the EGR circuit.
  53. When the actions have been carried out, always check that the fault code has disappeared.
  54. Run the wizard EMS > E 44 > S8 > Check > Check the EGR circuit to verify that the fault has been rectified.
  55. Applies only to vehicles with Euro 5: If the operating time since the fault code was generated exceeds 10 hours, drain the EGR cooler.
  56. The reason for this is that there is a risk that condensed water has formed in the air-cooled EGR cooler while the EGR circuit was switched off.
  57. Drain the EGR cooler according to the instructions in the Workshop Manual > 01-65 EGR system > Air-cooled EGR cooler. | Rectify other fault codes related to the EGR circuit first.
  58. Then check: Actuator for EGR valve M28.
  59. Potential leakage in the EGR circuit or in the engine intake system.
  60. Run Functions > Check > Emission control > EGR system > EGR circuit leak test.
  61. That the EGR cooler is intact and not clogged.
  62. If the EGR cooler is clogged, the EGR cleaner will clean the radiator according to instructions in the Service Manual > 01-65 EGR circuit > Liquid-cooled EGR cooler > Cleaning of EGR cooler, 9- and 13-litre engine.
  63. The variable geometry turbocharger nozzle ring and electric motor.
  64. Run EMS > E 44 > S8 > Check > Condition test on the variable geometry turbocharger.
  65. Mass flow sensor T126.
  66. Charge air pressure sensor T122.
  67. Charge air temperature sensor T121.
  68. Exhaust gas pressure sensor T125.
  69. When the fault code is inactive, the high exhaust emissions warning lamp will go out.
  70. You may need to carry out a default setting of the EGR circuit.
  71. Run the wizard EMS > E44 > S8 > Calibration > Default setting and calibration of the EGR circuit.
  72. When the actions have been carried out, always check that the fault code has disappeared.
  73. Run the wizard EMS > E 44 > S8 > Check > Check the EGR circuit to verify that the fault has been rectified.
  74. Applies only to vehicles with Euro 5: If the operating time since the fault code was generated exceeds 10 hours, drain the EGR cooler.
  75. The reason for this is that there is a risk that condensed water has formed in the air-cooled EGR cooler while the EGR circuit was switched off.
  76. Drain the EGR cooler according to the instructions in the Workshop Manual > 01-65 EGR system > Air-cooled EGR cooler.

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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