General information

• The following procedure contains troubleshooting steps and information regarding the after treatment system.
• Leaks in the exhaust system can cause exhaust odor or white smoke.
• Inspect the exhaust piping for leaks, cracks, and loose connections. Refer to Removal and Installation
• Tighten the clamps, if necessary. Refer to Exploded View .
• It may be necessary to perform a stationary (parked) regeneration to locate exhaust leaks. Refer to "DPF REGENERATION TEST"
• The ambient temperature affects the length of time it will take to perform a stationary (parked) regeneration, because the engine must work harder to increase the exhaust temperatures to the appropriate levels in cold ambient temperatures.
• In cold ambient temperatures (approximately -18°C [0°F] or colder), stationary (parked) regeneration may take longer to complete. In extremely cold ambient temperatures, stationary (parked) regeneration may not  complete.
• In these cases, it may be necessary to warm the engine to operating temperature before starting the stationary (parked) regeneration, or to move the vehicle to a location with higher ambient temperatures.

Stationary Regeneration (Parked)

• When performing a stationary (parked) regeneration, monitor the exhaust temperatures in the after treatment system to determine why a stationary (parked) regeneration will not  complete.
• Possible causes for stationary (parked) regenerations that will not  complete include:
  • Mis-assembled after treatment wiring harness.
  • After treatment exhaust gas temperature sensors installed in the wrong locations.
  • Plugged diesel oxidation catalyst (DOC).
  • Malfunctioning turbocharger.
  • Exhaust leaks between the engine and the after treatment.
  • Very low ambient temperatures (less than -18°C [0°F]).
• A normal stationary (parked) regeneration will follow the pattern shown.

  Courtesy of NISSAN NORTH AMERICA, INC.

  (D)	: Temperature
  (E)	: Time

  • The dashed line is for the DOC inlet temperature sensor (F).
  • The dotted line is for the diesel particulate filter (DPF) inlet temperature sensor (B).
  • The solid line is for the DPF outlet temperature sensor (A).
• When the stationary (parked) regeneration begins (C), all three temperatures should be approximately the same, and should increase at the same rate.
• The wiring to the after treatment temperature sensors appears to be correct in this example, because they all read approximately the same temperature at the beginning of the stationary (parked) regeneration and increase at the same rate.
• The DPF inlet and outlet temperatures will increase over approximately 10 minutes to 482 to 649°C [900 to 1200°F]. The temperatures may vary during the stationary (parked) regeneration, as the amount of fuel injected during after treatment injection is changed to maintain a constant temperature.
• The DPF inlet and outlet temperatures will remain at this temperature for the duration of the stationary (parked) regeneration.

Stationary Regeneration (DOC and DPF Assembly Blocked)

• This graph illustrates a stationary (parked) regeneration where the inlet of the DOC is blocked.

  Courtesy of NISSAN NORTH AMERICA, INC.

  (E)	: Temperature
  (F)	: Time

  • The dashed line is for the DOC inlet temperature sensor (B).
  • The dotted line is for the DPF inlet temperature sensor (C).
  • The solid line is for the DPF outlet temperature sensor (A).
• In this condition, the engine speed will increase to the stationary (parked) regeneration speed of 1000 to 1100 RPM.
• The wiring to the after treatment temperature sensors appears to be correct in this example, because they all read approximately the same temperature at the beginning of the stationary (parked) regeneration and they increase at the same rate.
• The possible cause of this condition is a plugged DOC. Use the following procedure to inspect the DOC. Inspect the exhaust and after treatment system for leaks. Tighten clamps as necessary. Reference the appropriate procedure for torque specifications.

Stationary Regeneration (Cold Engine)

• This graph illustrates a stationary (parked) regeneration where the engine can not  build enough heat to start after treatment injection.

  Courtesy of NISSAN NORTH AMERICA, INC.

  (C)	: Temperature
  (D)	: Time

  • The dashed line is for the DOC inlet temperature sensor (A).
  • The dotted line is for the DPF inlet temperature sensor (E).
  • The solid line is for the DPF outlet temperature sensor (B).
• The engine speed will likely increase to the stationary (parked) regeneration speed of 1000 to 1100 RPM, but because the after treatment temperatures do not  increase enough to start after treatment injection, the stationary (parked) regeneration will not  complete.
• The wiring to the after treatment temperature sensor appears to be correct in this example, because they all read approximately the same temperature for the same conditions.
• Possible causes of this issue include:
  • A malfunctioning turbocharger.
  • Low ambient temperatures. Move the vehicle to a location with higher ambient temperatures.

Stationary Regeneration (Incorrect Wire Routing)

• This graph illustrates a stationary (parked) regeneration where the wiring to the after treatment temperature sensors is incorrect.

  Courtesy of NISSAN NORTH AMERICA, INC.

  (B)	: Temperature
  (D)	: Time

  • The dashed line is for the DOC inlet temperature sensor (C).
  • The dotted line is for the DPF inlet temperature sensor (E).
  • The solid line is for the DPF outlet temperature sensor (A).
• In this condition, the engine speed will increase to the stationary (parked) regeneration speed of 1000 to 1100 RPM.
• After treatment injection will not  occur in this condition because the DOC inlet temperature does not  reach the required temperature. Because after treatment injection is not  occurring, the after treatment temperatures should not  read differently.
• The possible cause of this condition is an incorrectly assembled after treatment wiring harness. See the after treatment exhaust gas temperature sensor wiring information in this procedure.

• This graph illustrates a stationary (parked) regeneration where the connectors to the DOC inlet temperature sensor and the DPF outlet temperature sensor are reversed.

  Courtesy of NISSAN NORTH AMERICA, INC.

  (B)	: Temperature
  (D)	: Time

  • The dashed line is for the DOC inlet temperature sensor (C).
  • The dotted line is for the DPF inlet temperature sensor (A).
  • The solid line is for the DPF outlet temperature sensor (E).
• In this condition, the engine speed will increase to the stationary (parked) regeneration speed of 1000 to 1100 RPM.
• After treatment injection may occur in this condition. However, the DOC inlet temperature increases after treatment injection begins, while the DPF outlet temperature remains constant.
• The possible cause of this condition is that the connectors to the DOC inlet temperature sensor and the DPF outlet temperature sensor are reversed. See the after treatment exhaust gas temperature sensor wiring information in this procedure.