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Home >> Infiniti >> 2024 >> QX50 Pure, FWD >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System (1 Of 2) >> System Description >> System >> Engine Control System >> Fail-safe
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Engine Control System: Fail-safe

Engine Control System 

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: SYMBOL ECM does not control the accelerator pedal releasing speed.
 A
Engine output control 1 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.
NOTE: SYMBOL 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
Engine output control 2 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 40 km/h (25 MPH) or more is possible.
NOTE: SYMBOL 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.
 C
Device fix mode
  • This mode fixes 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).
 D
Combustion control mode Stratified charge combustion control at starting No stratified charge combustion at starting (cold start). E
Idle speed control Stops feedback control of idle speed and controls with specified speed. F
Recovery speed control at decelerating Stops recovery speed control by the fuel cut at decelerating and controls with specified speed.
Ignition timing correction control Partially controls ignition timing control. G
Retardation control Controls ignition timing delay control in the intermediate water temperature range.

Fail-Safe List 

x: Applicable, -: Not applicable

DTC No. Detected items Vehicle behavior
Pattern Others
A B C D E F G
P0010 Electric intake valve timing module - - - x x - - ECM stops the electric valve timing control. (The camshaft returns to the position of most retard angle.)
- - - x - x -
P0011, P0012, P052A, P052B Intake valve timing control - - - x - - - ECM stops the electric valve timing control. (The camshaft returns to the position of most retard angle.)
P0014, P0015 Exhaust valve timing control - - - x - - - -
P0046 Wastegate control actuator - x - x - - -  
P0078 Exhaust valve timing control solenoid valve - - - x - - - -
P0087, P0088 FRP control system x - - x x - - -
x - - - x - -
P0090 x - - x x - -
P0101 Mass air flow sensor circuit x - - - x - - -
- x - x - - x
P0102, P0103 - x - x - - x -
P0117, P0118 Engine coolant temperature sensor circuit - - - - - x - -
P0122, P0123, P0222, P0223, P2135 Throttle position sensor - - - x - - - The ECM controls the electric throttle control actuator in regulating the throttle opening in order for the idle position to be within +10 degrees. The ECM regulates the opening speed of the throttle valve to be slower than the normal condition. So, the acceleration will be poor.
NOTE: SYMBOL If throttle position sensor 1 and 2 malfunction at the same time conducts following control.
  • ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
P0171, P0172 Direct fuel injection system x - - - - x - -
P0190 FRP sensor x - - x - x - -
P0191, P0192, P0193 x - - - x - - -
P0196, P0197, P0198 Engine oil temperature sensor - - - - - - - Intake and exhaust valve timing control does not function.
P0201, P0202, P0203, P0204 Direct fuel injector x - - x x - - -
P0235 Turbocharger boost sensor - x - x - - - -
P0237
P0238
P0261, P0264, P0267, P0270 Direct fuel injector x - - x x - -  
P0262, P0265, P0268, P0271 x - - x x - -
P0300, P0301, P0302, P0303, P0304 Misfire x - - - - x - -
P0335 Crankshaft position sensor - - - x - x - -
- - - x x - -
- - - x - - -
P0340 Camshaft position sensor - - - x - x - -
- - - x x - -
- - - x - - -
P0365 Exhaust valve timing control position sensor - - - x - - - -
P0500 Vehicle speed sensor x - - - - x - -
P0524 Engine oil pressure - - - - - - -
  • ECM illuminates engine oil pressure warning lamp on the combination meter.
  • Engine speed will not rise more than 4, 000 RPM due to the fuel cut.
  • Fail-safe is canceled when ignition switch OFF → ON.
P0603 ECM - x - - - - - -
P0604 - - - x - - - (Computing part of ECM does not operate normally). ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
P0605 - - - - - - - -
- - - x - - - (Computing part of ECM does not operate normally). ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
P0606 - - - - - - - -
- - - x - - - ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
P0607 - - - - - - - -
- x - - - - - ProPILOT assist operation may be deactivated.
P060A - - - x - - - ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
- x - x - - -
  • ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
  • ProPILOT assist operation may be deactivated.
P060B, P061B - - - x - - - ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
P060C - - - x - - - (Computing part of ECM does not operate normally). ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
P062B - - - - - - - -
x - - x x - -
P062D x - - x x - -  
P0641 Sensor power supply - - - x - x - ECM stops the electric valve timing control. (The camshaft returns to the position of most retard angle.)
- - - x x - -
P0643 - - - x - - - ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
P10C0 Direct fuel injector x - - x x - -  
P10C8, P10C9, P10CA, P10CB Direct fuel injector x - - x x - -  
P1197 Out of gas - - - x - - - Engine torque is limited.
P11A0 VCR control module - - - - - - -
  • Engine speed limited
  • Stop turbocharger boost control
  • VCR motor OFF
P11A1 VCR motor - - - - - - -
  • Engine speed limited
  • Stop turbocharger boost control
  • VCR motor OFF
P11A2 VCR motor rotation angle sensor - - - - - - -
  • Engine speed limited
  • Stop turbocharger boost control
  • VCR motor OFF
P11A3 Variable compression ratio motor resolver - - - - - - -
  • Engine speed limited
  • Stop turbocharger boost control
  • VCR motor OFF
P11A4 VCR motor rotation angle sensor - - - - - - -
  • Engine speed limited
  • Stop turbocharger boost control
  • VCR motor OFF
P11A6 VCR rotation angle sensor mutual - - - - - - -
  • Engine speed limited
  • Stop turbocharger boost control
  • VCR motor OFF
P11A7 VCR stopper position - - - - - - -
  • Engine speed limited
  • Stop turbocharger boost control
  • VCR motor OFF
P11AA VCR position learning - - - - - - - Fix low compression ratio
P11AB VCR control module circuit - - - - - - -
  • Engine speed limited
  • Stop turbocharger boost control
  • VCR motor OFF. These fail-safe may not be executed.
P11AC, P11AD, P11AE, P11AF VCR shaft 2 rotation angle sensor - - - - - - -
  • Engine speed limited
  • Stop turbocharger boost control
  • VCR motor OFF
P1217 Engine over temperature - - - - - - - Engine speed is limited due to the fuel cut.
P1805 Brake switch - - - - - - - ECM controls the electric throttle control actuator by regulating the throttle opening to a small range. Therefore, acceleration will be poor.
Vehicle condition Driving condition
When engine is idling Normal
When accelerating Poor acceleration
P2100, P2103 Throttle control motor relay - - - x - - - ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
P2101 Electric throttle control function - - - x - - - ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
P2118 Throttle control motor - - - x - - - ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
P2119 Electric throttle control actuator - x - - - - - -
- - - x - - - ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
NOTE: SYMBOL For pattern A and B refer to A and B of P2119 DTC detection logic. (Refer to DTC Description ). For C of P2119 DTC detection logic ECM behaves as above.
P2122, P2123, P2127, P2128, P2138 Accelerator pedal position sensor - - - x - - - The ECM controls the electric throttle control actuator in regulating the throttle opening in order for the idle position to be within +10 degrees. The ECM regulates the opening speed of the throttle valve to be slower than the normal condition. Therefore, the acceleration will be poor.
NOTE: SYMBOL If accelerator pedal position sensor 1 and 2 malfunction at the same time conducts following control.
  • ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
P21CF, P21D0, P21D1, P21D2, P21DB, P21DE, P21E0, P21E2, P21DC, P21DF, P21E1, P21E3 Port fuel injector x - - x x - - -
P21F4, P21F5 Fuel system x - - - - x - -
P2562, P2566 Electric wastegate control valve position sensor - x - x - - - The ECM stops the electric wastegate actuator control, engine can not be supercharged driving. The ECM regulates engine power limiter and EGR Off.
P2563, P2564, P2565 Electric wastegate control valve position sensor - x - x - - - -
P2614, P2615 Intake camshaft position sensor - - - x - x - ECM stops the electric valve timing control. (The camshaft returns to the position of most retard angle.)
P2616 - - - x x - -
P2617 Crankshaft position sensor - - - x x - - ECM stops the electric valve timing control. (The camshaft returns to the position of most retard angle.)
P2618 - - - x x - -
P2619 - - - x - x -
P26A3, P26A5, P26A6, P26A7 Multi-way control valve - - - - - - -
  • When detecting a malfunction with the valve closed, ECM fully opens the valve.
  • When detecting a malfunction with the valve opened, ECM maintains valve angle.
  • When detecting a malfunction in sensor, ECM fully opens the valve.
  • ECM limits the engine output depending on malfunctions.
P34AC, P34AD Electric intake valve timing control actuator - - - x x - - -
- - - x x - - -
P34AE, P34AF Electric intake valve timing control position sensor - - - x x - - -
P34C8 Electric intake valve timing control module - - - x x - - ECM stops the electric valve timing control. (The camshaft returns to the position of most retard angle.)
- - - x x x -
U012E, U042F CAN communication line - - - x - x - ECM stops the electric valve timing control. (The camshaft returns to the position of most retard angle.)
- - - x x - -
U10A0 Lost communication (Variable compression ratio) - - - - - - -
  • Engine speed limited
  • Stop turbocharger boost control
  • VCR motor OFF
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