Description
The service engine soon/malfunction indicator lamp power is supplied from the ignition switch. The PCM controls the ground of the service engine soon/malfunction indicator lamp by turning the power transistor in the PCM on and off. The PCM causes the service engine soon/malfunction indicator lamp to illuminate for 5 seconds immediately after the ignition switch is turned to ON position. (Scheme 42)
Scheme 42
The service engine soon/malfunction indicator lamp power is supplied from the ignition switch. The PCM controls the ground of the service engine soon/malfunction indicator lamp by turning the power transistor in the PCM on and off. In such cases, the cause is probably that the PCM is detecting a problem in a sensor or actuator, or that one of the malfunctions listed in troubleshooting hints has probably occurred. (Scheme 42)
A battery positive voltage is applied on the data link connector power terminal (terminal No. 16). The ground terminals (terminals No. 4 and 5) are grounded to the vehicle body. The cause is probably a defect in power supply system (including ground) for the on-board diagnostic test mode line. (Scheme 43)
Scheme 43
A diagnostic output is made from the PCM (terminal No. 85) to the diagnostic output terminal (terminal No. 7) of the data link connector. (Scheme 44)
Scheme 44
CONNECTOR IDENTIFICATION
Note. The following connector illustrations are shown as viewed from component side of connector.
| Connector | Illustration |
|---|---|
| Auto Cruise Control ECU | (Scheme 45) |
| Camshaft Position (CMP) Sensor | (Scheme 46) |
| Crankshaft Position (CKP) Sensor | (Scheme 47) |
| Data Link Connector | (Scheme 48) |
| EGR Solenoid | (Scheme 49) |
| Engine Coolant Temperature (ECT) Sensor | (Scheme 50) |
| Fuel Injector | (Scheme 51) |
| Fuel Pump Module | (Scheme 52) |
| Fuel Pump Relay | (Scheme 53) |
| Fuel Tank Differential Pressure (FTDP) Sensor | (Scheme 54) |
| Generator Field | (Scheme 55) |
| Heated Oxygen Sensor (HO2S) (Front) | (Scheme 56) |
| Heated Oxygen Sensor (HO2S) (Rear) | (Scheme 57) |
| Idle Air Control (IAC) Motor | (Scheme 58) |
| Ignition Switch | (Scheme 59) |
| Immobilizer ECU | (Scheme 60) |
| Instrument Cluster | (Scheme 61) |
| Intermediate Connector B-11 | (Scheme 62) |
| Intermediate Connector C-17 | (Scheme 63) |
| Intermediate Connector C-57 | (Scheme 64) |
| Intermediate Connector C-71 | (Scheme 65) |
| Intermediate Connector D-15 | (Scheme 66) |
| Manifold Differential Pressure (MDP) Sensor | See scheme 52 |
| MFI Relay | (Scheme 53) |
| Powertrain Control Module (PCM) | (Scheme 67) |
| Purge Solenoid | (Scheme 68) |
| Throttle Position (TP) Sensor | (Scheme 69) |
| Ventilation Solenoid | See scheme 56 |
| Volume Airflow (VAF) Sensor | (Scheme 70) |
TERMINAL IDENTIFICATION DIRECTORY
Scheme 45
Scheme 46
Scheme 47
Scheme 48
Scheme 49
Scheme 50
Scheme 51
Scheme 52
Scheme 53
Scheme 54
Scheme 55
Scheme 56
Scheme 57
Scheme 58
Scheme 59
Scheme 60
Scheme 61
Scheme 62
Scheme 63
Scheme 64
Scheme 65
Scheme 66
Scheme 67
Scheme 68
Scheme 69
Scheme 70
While the engine is running, the volume air flow sensor outputs a pulse signal which corresponds to the volume of air flow. The PCM checks whether the frequency of this signal output by the volume air flow sensor while the engine is running is at or above the set value. When the throttle position sensor output voltage is low, the PCM causes the power transistor to be ON to send an air flow sensor reset signal to the air flow sensor. In response to the reset signal, the air flow sensor resets the filter circuit and improves the ability of the air flow sensor to measure the amount of air in a small air intake region.
Operation
The volume air flow sensor power is supplied from the MFI relay (terminal No. 4), and the ground is provided on the PCM (terminal No. 16). 5-volt power is applied to the volume air flow sensor output terminal (terminal No. 3) from the PCM (terminal No. 65). The volume air flow sensor generates a pulse signal when the output terminal and ground are opened/closed (Open/Short).
see scheme 1, see scheme 25, see scheme 27, see scheme 29 and (Scheme 71).
Scheme 71
While the engine is running, the volume air flow sensor outputs a pulse signal which corresponds to the volume of air flow. The PCM checks whether the frequency of this signal output by the volume air flow sensor while the engine is running is at or above the set value.
The volume air flow sensor power is supplied from the MFI relay (terminal No. 4), and the ground is provided on the PCM (terminal No. 16). 5-volt power is applied to the volume air flow sensor output terminal (terminal No. 3) from the PCM (terminal No. 65). The volume air flow sensor generates a pulse signal when the output terminal and ground are opened/closed (open/short).
see scheme 1, see scheme 25, see scheme 27, see scheme 29 and (Scheme 71).
A 5-volt voltage is supplied to the barometric pressure sensor power terminal (terminal No. 1) from the PCM (terminal No. 46). The ground terminal (terminal No. 5) is grounded with PCM (terminal No. 16). A voltage that is proportional to the atmospheric pressure is sent to the PCM (terminal No. 55) from the barometric pressure sensor output terminal (terminal No. 2).
see scheme 27, see scheme 29 and (Scheme 72).
Scheme 72
The barometric pressure sensor outputs a voltage which corresponds to the barometric pressure. The PCM checks whether this voltage is within a specified range.
A 5-volt voltage is supplied to the barometric pressure sensor power terminal (terminal No. 1) from the PCM (terminal No. 46). The ground terminal (terminal No. 5) is grounded with PCM (terminal No. 16). A voltage that is proportional to the atmospheric pressure is sent to the PCM (terminal No. 55) from the barometric pressure sensor output terminal (terminal No. 2).
see scheme 27, see scheme 29 and (Scheme 72).
The barometric pressure sensor outputs a voltage which corresponds to the barometric pressure. The PCM checks whether this voltage is within a specified range.
A 5-volt voltage is supplied to the barometric pressure sensor power terminal (terminal No. 1) from the PCM (terminal No. 46). The ground terminal (terminal No. 5) is grounded with PCM (terminal No. 16). A voltage that is proportional to the atmospheric pressure is sent to the PCM (terminal No. 55) from the barometric pressure sensor output terminal (terminal No. 2).
see scheme 27, see scheme 29 and (Scheme 72).
The barometric pressure sensor outputs a voltage which corresponds to the barometric pressure. The PCM checks whether this voltage is within a specified range.
The intake air temperature sensor converts the intake air temperature to a voltage. The PCM checks whether this voltage is within a specified range.
Approximately 5 volts are applied to the intake air temperature sensor output terminal (terminal No. 6) from the PCM (terminal No. 64) via the resistor in the PCM. The ground terminal (terminal No. 5) is grounded with PCM (terminal No. 16). The intake air temperature sensor is a negative temperature coefficient type of resistor. When the intake air temperature rises, the resistance decreases. The intake air temperature sensor output voltage increases when the resistance increases and decreases when the resistance decreases.
see scheme 27, see scheme 29 and (Scheme 73).
Scheme 73
The intake air temperature sensor converts the intake air temperature to a voltage. The PCM checks whether this voltage is within a specified range.
Approximately 5 volts are applied to the intake air temperature sensor output terminal (terminal No. 6) from the PCM (terminal No. 64) via the resistor in the PCM. The ground terminal (terminal No. 5) is grounded with PCM (terminal No. 16). The intake air temperature sensor is a negative temperature coefficient type of resistor. When the intake air temperature rises, the resistance decreases. The intake air temperature sensor output voltage increases when the resistance increases and decreases when the resistance decreases.
see scheme 27, see scheme 29 and (Scheme 73).
The intake air temperature sensor converts the intake air temperature to a voltage. The PCM checks whether this voltage is within a specified range.
Approximately 5 volts are applied to the intake air temperature sensor output terminal (terminal No. 6) from the PCM (terminal No. 64) via the resistor in the PCM. The ground terminal (terminal No. 5) is grounded with PCM (terminal No. 16). The intake air temperature sensor is a negative temperature coefficient type of resistor. When the intake air temperature rises, the resistance decreases. The intake air temperature sensor output voltage increases when the resistance increases and decreases when the resistance decreases.
see scheme 27, see scheme 29 and (Scheme 73).
The engine coolant temperature sensor converts the engine coolant temperature to a voltage and outputs it. The PCM checks whether this voltage is within a specified range.
5-volt voltage is applied to the engine coolant temperature sensor output terminal (terminal No. 1) from the PCM (terminal No. 44) via the resistor in the PCM. The ground terminal (terminal No. 2) is grounded with PCM (terminal No. 57). The engine coolant temperature sensor is a negative temperature coefficient type of resistor. It has the characteristic that when the engine coolant temperature rises the resistor decreases. The engine coolant temperature sensor output voltage increases when the resistor increases and decreases when the resistor decreases.
see scheme 10, see scheme 27 and (Scheme 74).
Scheme 74
The engine coolant temperature sensor converts the engine coolant temperature to a voltage and outputs it. The PCM checks whether this voltage is within a specified range.
5-volt voltage is applied to the engine coolant temperature sensor output terminal (terminal No. 1) from the PCM (terminal No. 44) via the resistor in the PCM. The ground terminal (terminal No. 2) is grounded with PCM terminal No. 57. The engine coolant temperature sensor is a negative temperature coefficient type of resistor. It has the characteristic that when the engine coolant temperature rises the resistor decreases. The engine coolant temperature sensor output voltage increases when the resistor increases and decreases when the resistor decreases.
see scheme 10, see scheme 27 and (Scheme 74).
The engine coolant temperature sensor converts the engine coolant temperature to a voltage and outputs it. The PCM checks whether this voltage is within a specified range.
A 5-volt voltage is applied to the engine coolant temperature sensor output terminal (terminal No. 1) from the PCM (terminal No. 44) via the resistor in the PCM. The ground terminal (terminal No. 2) is grounded with PCM terminal No. 57. The engine coolant temperature sensor is a negative temperature coefficient type of resistor. It has the characteristic that when the engine coolant temperature rises the resistor decreases. The engine coolant temperature sensor output voltage increases when the resistor increases and decreases when the resistor decreases.
see scheme 10, see scheme 27 and (Scheme 74).
The TPS outputs voltage which corresponds to the throttle valve opening angle. The PCM checks whether the voltage is within a specified range.
A 5-volt power supply is applied on the TPS power terminal (terminal No. 4) from the PCM terminal No. 46. The ground terminal (terminal No. 1) is grounded with PCM terminal No. 57. When the throttle valve shaft is turned from the idle position to the fully opened position, the resistor between the TPS output terminal (terminal No. 3) and ground terminal will increase according to the rotation.
see scheme 27, see scheme 28 and (Scheme 75).
Scheme 75
The TPS outputs voltage which corresponds to the throttle valve opening angle. The PCM checks whether the voltage is within a specified range. In addition, it checks that the voltage output does not become too high while the engine is at idle.
A 5-volt power supply is applied on the TPS power terminal (terminal No. 4) from the PCM terminal No. 46. The ground terminal (terminal No. 1) is grounded with PCM terminal No. 57. When the throttle valve shaft is turned from the idle position to the fully opened position, the resistor between the TPS output terminal (terminal No. 3) and ground terminal will increase according to the rotation.
see scheme 27, see scheme 28 and (Scheme 75).
The TPS outputs voltage which corresponds to the throttle valve opening angle. The PCM checks whether the voltage is within a specified range. In addition, it checks that the voltage output does not become too high while the engine is at idle.
A 5-volt power supply is applied on the TPS power terminal (terminal No. 4) from the PCM terminal No. 46. The ground terminal (terminal No. 1) is grounded with PCM terminal No. 57. When the throttle valve shaft is turned from the idle position to the fully opened position, the resistor between the TPS output terminal (terminal No. 3) and ground terminal will increase according to the rotation.
see scheme 27, see scheme 28 and (Scheme 75).
The engine coolant temperature sensor varies resistance due to engine coolant temperature. The PCM supplies voltage to sensor. Voltage changes due to sensor resistance. PCM checks whether this voltage is within a specified range.
5-volt voltage is applied to the engine coolant temperature sensor output terminal (terminal No. 1) from the PCM terminal No. 44 via the resistor in the PCM. The ground terminal (terminal No. 2) is grounded with PCM terminal No. 57. The engine coolant temperature sensor is a negative temperature coefficient type of resistor. It has the characteristic that when the engine coolant temperature rises the resistance decreases. The engine coolant temperature sensor output voltage increases when the resistance increases and decreases when the resistance decreases.
see scheme 10, see scheme 27 and (Scheme 74).
The PCM checks the time for the engine coolant temperature to reach the judgment temperature.
The heated oxygen sensor (front) detects the concentration of oxygen in the exhaust gas; it converts those data to voltage, and inputs the resulting signals to the PCM. When the heated oxygen sensor (front) begins to deteriorate, the heated oxygen sensor signal response becomes poor. The PCM forcibly varies the air/fuel mixture to make it leaner and richer, and checks the response speed of the heated oxygen sensor (front). In addition, the PCM also checks for an open circuit in the heated oxygen sensor (front) output line.
see scheme 15, see scheme 27 and (Scheme 76).
Scheme 76
The heated oxygen sensor (front) detects the concentration of oxygen in the exhaust gas; it converts those data to voltage, and inputs the resulting signals to the PCM. When the heated oxygen sensor (front) begins to deteriorate, the heated oxygen sensor signal response becomes poor. The PCM forcibly varies the air/fuel mixture to make it leaner and richer, and checks the response speed of the heated oxygen sensor (front). In addition, the PCM also checks for an open circuit in the heated oxygen sensor (front) output line.
A voltage corresponding to the oxygen concentration in the exhaust gas is sent to the PCM terminal No. 71 from the output terminal (terminal No. 4) of the heated oxygen sensor (front) terminal No. 2 of the heated oxygen sensor (front) is grounded with PCM terminal No. 57.
see scheme 15, see scheme 27 and (Scheme 76).
The PCM effects air/fuel ratio feedback control in accordance with the signals from the heated oxygen sensor (front). If the heated oxygen sensor (front) has deteriorated, corrections will be made by the heated oxygen sensor (rear). DTC P0134 becomes stored in memory if a failure is detected in the above air/fuel ratio feedback control system.
Refer to DTC P0132: HEATED OXYGEN SENSOR CIRCUIT HIGH VOLTAGE and DTC P0201, DTC P0202, DTC P0203 OR DTC P0204.
see scheme 15, see scheme 27 and (Scheme 76).
The PCM checks whether the heater current is within a specified range when the heater is energized.
Power is supplied from the MFI relay (terminal No. 4) to the heated oxygen sensor (front) heater. The PCM (terminal No. 3) controls continuity to the heated oxygen sensor (front) heater by turning the power transistor on and off in the PCM.
see scheme 15, see scheme 25, see scheme 27 and see scheme 66.
Scheme 77
The output signal of the heated oxygen sensor (front) is compensated by the output signal of the heated oxygen sensor (rear). The PCM checks for an open circuit in the heated oxygen sensor (rear) output line.
A voltage corresponding to the oxygen concentration in the exhaust gas is sent to the PCM terminal No. 73 from the output terminal (terminal No. 3) of the heated oxygen sensor (rear). Terminal No. 4 of the heated oxygen sensor (rear) is grounded with PCM terminal No. 57.
The output signal of the heated oxygen sensor (front) is compensated by the output signal of the heated oxygen sensor (rear). The PCM checks for an open circuit in the heated oxygen sensor (rear) output line.
A voltage corresponding to the oxygen concentration in the exhaust gas is sent to the PCM terminal No. 73 from the output terminal (terminal No. 3) of the heated oxygen sensor (rear) terminal No. 4 of the heated oxygen sensor (rear) is grounded with PCM terminal No. 57.
see scheme 16, see scheme 27 and see scheme 67.
The output signal of the heated oxygen sensor (front) is compensated by the output signal of the heated oxygen sensor (rear). The PCM checks for an open circuit in the heated oxygen sensor (rear) output line.
A voltage corresponding to the oxygen concentration in the exhaust gas is sent to the PCM terminal No. 73 from the output terminal (terminal No. 3) of the heated oxygen sensor (rear) terminal No. 4 of the heated oxygen sensor (rear) is grounded with PCM terminal No. 57.
see scheme 16, see scheme 27 and see scheme 67.
Power is supplied from the MFI relay (terminal No. 4) to the heated oxygen sensor (rear) heater. The PCM terminal No. 26 controls continuity to the heated oxygen sensor (rear) heater by turning the power transistor in the PCM on and off. The PCM checks whether the heater current is within a specified range when the heater is energized.
see scheme 16, see scheme 25, see scheme 27 and (Scheme 79).
Scheme 78
If a malfunction occurs in the fuel system, the fuel trim value becomes too large. The PCM checks whether the fuel trim value is within a specified range.
Refer to DTC P0201, DTC P0202, DTC P0203 OR DTC P0204.
see scheme 18and see scheme 27.
If a malfunction occurs in the fuel system, the fuel trim value becomes too small. The PCM checks whether the fuel trim value is within a specified range.
Refer to DTC P0201, DTC P0202, DTC P0203 OR DTC P0204.
The fuel temperature sensor converts the fuel temperature to a voltage. The PCM detects the fuel temperature in the fuel tank with this output voltage.
5-volt voltage is applied to the fuel temperature sensor output terminal (terminal No. 3) from the PCM terminal No. 51 via the resistor in the PCM. The fuel temperature sensor output voltage increases when the resistance increases and decreases when the resistance decreases. The ground terminal (terminal No. 1) is grounded to the vehicle body.
see scheme 20, see scheme 21, see scheme 23, see scheme 27 and (Scheme 80).
Scheme 79
The fuel temperature sensor converts the fuel temperature to a voltage. The PCM detects the fuel temperature in the fuel tank with this output voltage.
5-volt voltage is applied to the fuel temperature sensor output terminal (terminal No. 3) from the PCM terminal No. 51 via the resistor in the PCM. The fuel temperature sensor output voltage increases when the resistance increases and decreases when the resistance decreases. The ground terminal (terminal No. 1) is grounded to the vehicle body.
see scheme 20, see scheme 21, see scheme 23, see scheme 27 and (Scheme 80).
The fuel temperature sensor converts the fuel temperature to a voltage. The PCM detects the fuel temperature in the fuel tank with the output voltage.
5-volt voltage via the resistor in the PCM is applied to the fuel temperature sensor output terminal (terminal No. 3) from the PCM terminal No. 51. The fuel temperature sensor output voltage increases when the resistance increases and decreases when the resistance decreases. The ground terminal (terminal No. 1) is grounded to the vehicle body.
see scheme 20, see scheme 21, see scheme 23, see scheme 27 and (Scheme 80).
The amount of fuel injected by the injector is controlled by the amount of continuity time the coil is grounded by the PCM. A surge voltage is generated when the injectors are driven and the current flowing to the injector coil is shut off. The PCM checks this surge voltage.
The injector power is supplied from the MFI relay to each injector (terminal No. 1). The PCM controls the injector by turning the power transistor in the PCM on and off.
see scheme 18, see scheme 25, see scheme 27 and (Scheme 81).
Scheme 80
If a misfire occurs while the engine is running, the engine speed changes for an instant. The PCM checks for such changes in engine speed.
Refer to DTC P0201, DTC P0202, DTC P0203 OR DTC P0204. see scheme 18and see scheme 27.
If a misfire occurs while the engine is running, the engine speed changes for an instant. The PCM checks for such changes in engine speed.
Refer to DTC P0201, DTC P0202, DTC P0203 OR DTC P0204. see scheme 18and see scheme 27.
The crankshaft position sensor detects the crank angle (position) of each cylinder, and converts that data to pulse signals, which are then input to the PCM When the engine is running, the crankshaft position sensor outputs a pulse signal. The PCM checks whether pulse signal is input while the engine is cranking.
The crankshaft position sensor power (terminal No. 3) is supplied from the MFI relay (terminal No. 4). Terminal No. 1 of the crankshaft position sensor is grounded with PCM terminal No. 16. A 5-volt voltage is applied on the crankshaft position sensor output terminal (terminal No. 2) from PCM terminal No. 45. The crankshaft position sensor generates a pulse signal when the output terminal is opened and grounded.
see scheme 8, see scheme 25, see scheme 27 and (Scheme 83).
Scheme 81
The camshaft position sensor functions to detect the top dead center position of the number 1 cylinder and to convert that data to pulse signals that are input to the PCM. When the engine is running, the camshaft position sensor outputs a pulse signal. The PCM checks whether pulse signal is input while the engine is cranking.
The camshaft position sensor power is supplied from the MFI relay (terminal No. 4) terminal No. 1 of the camshaft position sensor is grounded with PCM terminal No. 16. A 5-volt voltage is applied on the camshaft position sensor output terminal (terminal No. 2) from the PCM terminal No. 56. The camshaft position sensor generates a pulse signal when the output terminal is opened and grounded.
see scheme 7, see scheme 25, see scheme 27 and (Scheme 85).
Scheme 82
When the EGR solenoid switches from OFF to ON while the engine is running, EGR gas flows. The PCM checks how the EGR gas flow signal changes.
The PCM checks current flows in the EGR solenoid drive circuit when the EGR solenoid is on and off.
The EGR solenoid power is supplied from the MFI relay (terminal No. 4). The PCM controls the EGR solenoid ground by turning the power transistor on and off in the PCM.
see scheme 9, see scheme 19, see scheme 25, see scheme 27 and (Scheme 87).
Scheme 83
The signal from the rear heated oxygen sensor differs from the front heated oxygen sensor. That is because the catalytic converter purifies exhaust gas. When the catalytic convener has deteriorated, the signal from the front heated oxygen sensor becomes similar to the rear heated oxygen sensor. The PCM compares the output of the front and rear heated oxygen sensor signals.
PCM detects stuck open of evaporative emission purge solenoid valve and stuck close of evaporative emission ventilation solenoid valve by pressure change in fuel tank. Stuck open of evaporative emission purge solenoid valve is judged through monitoring leak of evaporative emission control system. Stuck close of evaporative emission ventilation solenoid valve is judged after 20 seconds of end of monitoring leak of evaporative emission control system, or of usual operation of evaporative emission purge solenoid from ON to OFF.
see scheme 11and see scheme 12.
To judge if there is leak in the fuel system, the PCM measures the change of pressure inside the fuel tank. The PCM turns on the evaporative emission ventilation solenoid to shut off the evaporative emission canister outlet port. Then the evaporative emission purge solenoid is driven to set the fuel system into a negative pressure. When the fuel system develops a vacuum of 2 kPa (0.29 psi), the evaporative emission purge solenoid is turned OFF and the fuel system vacuum is maintained at 2 kPa (0.29 psi). The PCM determines if there is leak in the fuel system by measuring the change of vacuum inside the fuel tank. The test is stopped when fuel vapor pressure is judged as too high.
Scheme 84
Scheme 85
Scheme 86
Scheme 87
Scheme 88
Scheme 89
Scheme 90
Scheme 91
Scheme 92
Scheme 93
Scheme 94
Scheme 95
To judge if there is open circuit in the evaporative emission purge solenoid drive circuit, PCM measures the surge voltage of the evaporative emission ventilation solenoid coil. The PCM drives the evaporative emission purge solenoid for 30 milliseconds. After the solenoid is turned off, the PCM will check if the solenoid coil produces a surge voltage of 2 volts or more.
Power to the evaporative emission purge solenoid power is supplied from the MFI relay (terminal No. 4). The PCM controls ground of evaporative emission purge solenoid by turning the power transistor in the PCM on and off.
see scheme 11, see scheme 25, see scheme 27, (Scheme 88) and (Scheme 100).
Scheme 96
To judge if there is an open circuit in the evaporative emission ventilation solenoid drive circuit, PCM measures the surge voltage of the evaporative emission ventilation solenoid coil. The PCM drives the evaporative emission ventilation solenoid for 30 milliseconds. After the solenoid is turned off, the PCM will check if the solenoid coil produces a surge voltage of 2 volts or more.
The evaporative emission ventilation solenoid power is supplied from the MFI relay (terminal No. 4). The PCM controls the evaporative emission ventilation solenoid ground by turning the power transistor in the PCM ON and OFF.
see scheme 12, see scheme 20, see scheme 21, see scheme 22, see scheme 25, see scheme 27, (Scheme 88) and see scheme 93.
Scheme 97
To judge if the fuel tank differential pressure sensor is defective, the PCM monitors the fuel tank differential pressure sensor output voltage. Based on the test conditions and judgment criteria, the PCM judges if the fuel tank differential pressure sensor output voltage is normal.
A 5-volt voltage is supplied to the power terminal of the fuel tank differential pressure sensor terminal No. 3 from the PCM terminal No. 46. The sensor ground terminal (terminal No. 2) is grounded with the PCM terminal No. 57. A voltage proportional to the pressure in the fuel tank is sent from the output terminal of the fuel tank differential pressure sensor terminal No. 1 to the PCM terminal No. 92.
see scheme 13, see scheme 27, (Scheme 88) and (Scheme 101).
Scheme 98
Overview Of Troubleshooting
DTC P0451 can be set by faulty fuel differential pressure sensor, related circuit, or PCM.
To check a system blockage, do a performance test which uses a mechanical vacuum gauge and scan tool set on the fuel tank differential pressure sensor (TANK PRS SNSR73.) The mechanical gauge reading is used to verify scan tool reading. A comparison of the mechanical gauge to scan tool determines the problem in the system.
To judge if the fuel tank differential pressure sensor is defective, the PCM monitors the fuel tank differential pressure sensor output voltage. Based on the test conditions and judgment criteria, the PCM judges if the fuel tank differential pressure sensor output voltage is normal.
A 5-volt voltage is supplied to the power terminal of the fuel tank differential pressure sensor (terminal No. 3) from the PCM terminal No. 46. The sensor ground terminal (terminal No. 2) is grounded with PCM terminal No. 57. A voltage proportional to the pressure in the fuel tank is sent from the output terminal of the fuel tank differential pressure sensor (terminal No. 1) to the PCM terminal No. 92.
see scheme 13, see scheme 27, (Scheme 88) and (Scheme 101).
The DTC P0452 can be set if either faulty fuel differential pressure sensor, related circuit, or PCM.
To check a system blockage, do a performance test which uses a mechanical vacuum gauge and scan tool set on the fuel tank differential pressure sensor (TANK PRS SNSR73). The mechanical gauge reading is used to verify scan tool reading. A comparison of the mechanical gauge to scan tool determines the problem in the system.
To judge if the fuel tank differential pressure sensor is defective, the PCM monitors the fuel tank differential pressure sensor output voltage. Based on the test conditions and judgment criteria, the PCM judges if the fuel tank differential pressure sensor output voltage is normal.
A 5-volt voltage is supplied to the power terminal of the fuel tank differential pressure sensor (terminal No. 3) from the PCM terminal No. 46. The ground terminal (terminal No. 2) is grounded with the PCM terminal No. 57. A voltage proportional to the pressure in the fuel tank is sent from the output terminal of the fuel tank differential pressure sensor (terminal No. 1) to the PCM terminal No. 92.
see scheme 13, see scheme 27, (Scheme 88) and (Scheme 101).
The DTC P0453 can be set if a faulty fuel differential pressure sensor, related circuit, or PCM exists. To check a system blockage, do a performance test which uses a mechanical vacuum gauge and scan tool set on the fuel tank differential pressure sensor (TANK PRS SNSR73.) The mechanical gauge reading is used to verify scan tool reading. A comparison of the mechanical gauge to scan tool determines the problem in the system.
To judge if there is leak or clog in the fuel system, the PCM measures the change of the pressure inside the fuel tank. The PCM turns on the evaporative emission ventilation solenoid to shut off the evaporative emission canister outlet port. Then the evaporative emission purge solenoid is driven to set the fuel system into a negative pressure. When the fuel system develops a vacuum of 2 kPa (0.29 psi), the evaporative emission purge solenoid is turned off and the fuel system vacuum is maintained at 2 kPa (0.29 psi). The PCM determines if there is leak or clog in the fuel system by measuring the change of vacuum inside the fuel tank. The test is stopped when fuel vapor pressure is judged as too high.
see scheme 12, see scheme 20, see scheme 21, see scheme 22, see scheme 25, see scheme 27, (Scheme 88) and see scheme 93.
To determine the cause of DTC P0455, a performance test is needed. The performance test uses a mechanical vacuum gauge and scan tool set on the fuel tank differential pressure sensor (TANK PRES SNER 73). The mechanical gauge reading is used to verify scan tool reading. A comparison of the mechanical gauge reading to scan tool reading determines the reading problem in the system. Prior to doing the performance test, several simple inspections are needed to exclude some possibilities of the symptom.
To judge if there is leak in the fuel system, PCM measure the change of the pressure inside the fuel tank. The PCM turns on the evaporative emission ventilation solenoid valve to shot off the evaporative emission canister outlet port. Then the evaporative emission purge solenoid valve is driven to set the fuel system into a negative pressure. When the fuel system develops a vacuum of 2 kPa (0.29 psi), the evaporative emission purge solenoid valve is turned off and the fuel system vacuum is maintained at 2 kPa (0.29 psi). The PCM determines if there is leak in the fuel system by measuring the change of vacuum inside the fuel tank. The test is stopped when fuel vapor pressure is judged as too high.
see scheme 12, see scheme 20, see scheme 21, see scheme 22, see scheme 25, see scheme 27, (Scheme 88) and see scheme 93.
To determine the cause of DTC P0456, a performance test is needed. The performance test uses a mechanical vacuum gauge and scan tool set on the fuel tank differential pressure sensor (TANK PRES SNER 73.) The mechanical gauge reading is used to verify scan tool reading. A comparison of the mechanical gauge to scan tool determines the problem in the system. Prior to doing the performance test, several simple inspections are needed to exclude some possibilities of the symptom.
The drive signal from the fuel gauge circuit is split to the gauge and to input in PCM. The PCM detects the amount of fuel left in the fuel tank with this signal, and also controls the fuel level warning light.
The fuel gauge drive signal is input in PCM terminal No. 60.
see scheme 20, see scheme 21, see scheme 23, see scheme 27 and (Scheme 102).
Scheme 99
The amount of air taken in during idling is regulated by the opening and closing of the servo valve located in the air passage that bypasses the throttle body. If there is a malfunction of the IAC system, the actual engine speed will not be identical to the target engine speed. The PCM checks the difference between the actual engine speed and the target engine speed.
The idle air control motor power is supplied from the MFI relay (terminal No. 4). The PCM (terminals No. 14, 15, 28 and 29) drives the stepper motor by sequentially turning on the power transistors in the PCM and providing ground to the idle air control motor (terminals No. 1, 3, 4 and 6).
see scheme 17, see scheme 25, see scheme 27 and (Scheme 103).
Scheme 100
The amount of air taken in during idling is regulated by the opening and closing of the servo valve located in the air passage that bypasses the throttle body. If there is a malfunction of the IAC system, the actual engine speed will not be identical to the target engine speed. The PCM checks the difference between the actual engine speed and the target engine speed.
The idle air control motor power is supplied from the MFI relay (terminal No. 4). The PCM (terminals No. 14, 15, 28 and 29) drives the stepper motor by sequentially turning on the power transistors in the PCM and providing ground to the idle air control motor (terminals No. 1, 3, 4 and 6).
see scheme 17, see scheme 25, see scheme 27 and (Scheme 103).
The power steering pressure switch converts the existence of a power steering load into a high/low voltage, and inputs it into the PCM. When the steering wheel is turned, hydraulic pressure rises. The power steering pressure switch closes, and the applied battery positive voltage will be grounded. With this, the power steering pressure switch output voltage will fluctuate between 12 volts and 0 volt. While driving with the steering wheel held straight, the power steering pressure switch turns OFF. The PCM checks whether the power steering pressure switch turns OFF or ON during driving.
A battery positive voltage is applied to the power steering pressure switch output terminal (terminal No. 1) from the PCM terminal No. 52 via the resistor in the PCM.
see scheme 26, see scheme 27 and see scheme 98.
Scheme 101
The manifold differential pressure sensor outputs a voltage which corresponds to the negative pressure in the intake manifold. The PCM checks whether the voltage output by manifold differential pressure sensor is within a specified range.
A 5-volt voltage is applied on the manifold differential pressure sensor power terminal (terminal No. 3) from the PCM (terminal No. 46). The ground terminal (terminal No. 2) is grounded with the PCM terminal No. 57. A voltage proportional to the pressure in the intake manifold plenum is sent from the manifold differential pressure sensor output terminal (terminal No. 1) to the PCM terminal No. 91.
see scheme 24, see scheme 27 and see scheme 99.
Scheme 102
When the generator field coils are controlled, the generator FR terminal inputs signal to the PCM. The PCM detects the generator output with the input signal, and controls the idle air control motor according to the generator output.
The PCM (terminal No. 54) applies a battery positive voltage into the generator FR terminal No. 4 via resistance inside the unit.
see scheme 14, see scheme 19, see scheme 27 and see scheme 100.
Scheme 103
The PCM is checks the open circuit of battery backup line. When the system detects an open circuit in the battery backup line, it makes one failure judgment of other Diagnostic Trouble Codes (DTCs).
see scheme 27and see scheme 101.
Scheme 104
PCM monitors the communication condition with the immobilizer-ECU and the message from the immobilizer-ECU. When the abnormality is found, PCM prohibits engine start.
See also:
• WIRING DIAGRAMS