General sequence of testing
Caution: If the vehicle has a component that is not operating as designed and the Malfunction Indicator Lamp (MIL) is not illuminated, the component should not be replaced until the emission control system has been inspected unless the component is so damaged that the diagnostic system cannot confidently determine that a malfunction has occurred.
Emergency operation mode
When the following fault codes (DTCs) are generated, the ECM engine control module enters emergency mode and the fault warning lamp (MIL) lights up.
| Diagnostic trouble code number | The circuit or component being tested | Engine operating conditions in emergency mode | ||
| 1 | 2 | 3 | ||
| P0102 P0103 | Flow meter circuit (mass flow sensor)air | Engine speed will not exceed 2400 rpm due to fuel cut-off | ||
| P0117 P0118 | Coolant temperature sensor circuit | The engine coolant temperature will be determined by the ECM based on the time elapsed after the ignition key is turned to the "ON" or "START" position. The scan tool displays the coolant temperature determined by the ECM | ||
| Conditions | Engine coolant temperature (displayed on the device display) | |||
| The same as when turning the ignition key to the "ON" or "START" positions | 40°C | |||
| More than 4 minutes have passed since the ignition key was turned to the "ON" or "START" position | 80°C | |||
| In addition to the conditions specified above | 40-80°C (depending on time) | |||
| When the coolant temperature control emergency mode is activated, the cooling fan will run continuously while the engine is running | ||||
| P0122 P0123 P0222 P0223 R2135 | Throttle position sensor | The ECM controls the electric throttle actuator so that the throttle opening angle remains within +10° at idle. The ECM regulates the throttle opening speed so that it is lower than that observed under normal conditions. Because of this, the acceleration intensity will be reduced. | ||
| P1121 | Electric throttle control actuator | When the electric actuator for controlling the throttle valve does not work properly due to a malfunction of the return spring: The ECM controls the electric throttle control actuator so that the throttle opening angle is approximately the same as in idle mode. The engine speed will not exceed 2000 rpm | ||
| When the throttle valve opening angle during limp home operation is outside a certain range: The ECM controls the electric throttle actuator so that the throttle valve opening angle is 20° or less | ||||
| When the ECM detects that the throttle valve is stuck open: If the vehicle is moving, it is gradually slowed down by cutting off the fuel supply. After the car stops, the engine turns off. The engine can be started when the selector lever is in the "N" or "P" positions and the engine speed does not exceed 1000 rpm. | ||||
| P1122 | Electric throttle control function | The ECM stops the electric actuator controlling the throttle, and the throttle is maintained in a fixed position (open approximately 5°)by means of a return spring | ||
| P1124 R1126 | Throttle control motor relay | The ECM disengages the electrical actuator that controls the throttle valve and the throttle valve is held in a fixed position (approximately 5° open) by the return spring | ||
| R1128 | Throttle control motor | The ECM disengages the electrical actuator that controls the throttle valve and the throttle valve is held in a fixed position (approximately 5° open) by the return spring | ||
| R1229 | Applying voltage to the sensor | The ECM disengages the electrical actuator that controls the throttle valve and the throttle valve is held in a fixed position (approximately 5° open) by the return spring | ||
| R2122 R2123 R2127 R2128 R2138 | Accelerator pedal position sensor | The ECM controls the electric throttle actuator so that the throttle opening angle remains within +10° at idle. The ECM regulates the throttle opening speed so that it is lower than that observed under normal conditions. Because of this, the acceleration intensity will be reduced | ||
(Information obtained from the website: NISSANBOOK.RU)
If there is an open in the malfunction indicator lamp (MIL) circuit, the ECM cannot alert the driver of a malfunction in the engine management system by illuminating the MIL. Therefore, if the throttle body and ECM component diagnostics detect malfunctions during 5 consecutive driving cycles, the ECM alerts the driver of an engine management system malfunction and an open in the MIL circuit by activating the fail-safe mode. The limp home mode activation function also operates when the above-mentioned faults are detected, with the exception of a faulty MIL circuit. This alerts the driver to the need to correct the fault.