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Home >> Nissan-Datsun >> 2020 >> Altima SL, AWD >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System (Pr25DD) (1 Of 2) >> System Description >> System >> Engine Control System >> Fail-safe >> Description
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Engine Control System: Fail-safe: Description

When a DTC is detected, ECM executes a mode (in the Fail-safe mode) applicable to the DTC. The fail-safe mode has the preset traveling control mode (accelerator angle variation and engine output limit), device fix mode and combustion control mode.

Fail safe mode

Vehicle behavior

Fail safe pattern

Traveling control mode

Accelerator angle variation control

ECM controls the accelerator pedal depression speed to make it slower than actual speed. This causes a drop in accelerating performance and encourages the driver to repair malfunction.

NOTE: ECM does not control the accelerator pedal releasing speed.

A

Engine output control

ECM reduces the engine output, according to the rise in engine speed. This reduces the vehicle speed to encourage the driver to repair malfunction.

  • Driving at 70 km/h (44 MPH) or more is possible.
  • Driving at 40 km/h (25 MPH) or more is possible.
NOTE: This value is a reference value converted from engine power to vehicle speed. Actual power limitation value differs due to the malfunctioning part and driving condition.

B

Device fix mode
  • This mode fixes the electric IVT motor and the EVT control solenoid valve in the reference position.
  • The intake manifold runner control valve motor is turned OFF (intake manifold runner control valve opens).
  • A control signals is not transmitted to EGR volume control valve and the EGR volume control is deactivated.

C

Combustion control mode

Stratified charge combustion control at starting

No stratified charge combustion at starting (cold start).

D

Idle speed control

Stops feedback control of idle speed and controls with specified speed.

E

Recovery speed control at decelerating

Stops recovery speed control by the fuel cut at decelerating and controls with specified speed.

Idle neutral control

Stops idle neutral control.

Ignition timing correction control

Partially controls ignition timing control.

F

Retardation control

Controls ignition timing delay control in the intermediate water temperature range.
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