CHECK AT THE ENGINE-ECU TERMINALS


warning A high-tension voltage is flowing between the engine-ECU and the injectors while the engine is running. Handle them carefully to avoid receiving electric shocks from the voltage.

TERMINAL VOLTAGE CHECK CHART

1.Connect a needle-nosed wire probe to a voltmeter probe.
2.Insert the needle-nosed wire probe into each of the engine-ECU connector terminals from the wire side, and measure the voltage while referring to the check chart.
note
  1. Make the voltage measurement with the engine-ECU connector connected.
  2. You may find it convenient to pull out the engine-ECU to make it easier to reach the connector terminals.
  3. The checks can be carried out off the order given in the chart.
caution Short-circuiting the positive (+) probe between a connector terminal and earth could damage the vehicle wiring, the sensor, engine-ECU or all of them. Be careful to prevent this!
3.If voltmeter shows any division from standard value, check the corresponding sensor, actuator and related electrical wiring, then repair or replace.
4.After repair or replacement, recheck with the voltmeter to confirm that the repair has corrected the problem.
Terminal No.
 Check item
 Inspection condition (engine status)
 Normal condition
13
 A/C load signal
  • Engine:Idling after warning up the engine
  • A/C switch:ON

 A/C compressor clutch not in operation
 1 V or lower
A/C compressor clutch in operation
 1 V or lower <=> System voltage (Changes repeatedly)
14
 Select rail switch <M/T>
 Ignition switch: ON
 Shift position: 2nd, 4th, R
 System voltage
Shift position: 1st, 3rd, 5th
 1 V or lower
15
 A/C switch
 Engine: Idle speed (after warning up)
 A/C switch: OFF
 1 V or lower
A/C switch: ON
 System voltage
16
 Third and fourth rail switch <M/T>
 Ignition switch: ON
 Shift position: 3rd, 4th
 System voltage
Shift position: Except 3rd and 4th
 1 V or lower
17
 Suction control valve (positive)
 Engine: Idling
 5 - 6* V
Engine: Acceleration
 Decreases
19
 Exhaust gas recirculation motor (positive)
 Engine: Idling (after warning up)
 1.8 V or higher*
Engine: 3,500 r/min (after warning up)
 1.6 V or lower*
20
 EGR motor (negative)
 Engine: Idling (after warning up)
 1 - 3 V*
Engine: 3,500 r/min (after warning up)
 1 V or lower
29
 Glow plug relay
 Ignition switch: OFF → ON
 Engine coolant temperature: lower than 60 °C
 1 V or lower → System voltage (after several seconds have elapsed)
Engine coolant temperature: higher than 60 °C
 System voltage
35
 PTC heater control signal <vehicle with PTC heater>
  • Heater temperature setting: Maximum
  • Blower fan: ON

 System voltage
Other than the above
 1 V or lower
39
 Condenser fan relay
 Engine: Idling after warning up the engine
 A/C switch: OFF
 1 V or lower
A/C switch: ON
 1 V or lower<=> System voltage (Changes repeatedly)
40
 A/C relay
 Engine: Idle speed (after warning up)
 A/C switch: OFF
 System voltage
A/C switch: ON
 A/C compressor is not driven
 System voltage
A/C compressor is driven
 1 V or lower
41
 PTC heater relay 1 <vehicle with PTC heater>
  • Engine coolant temperature: lower than 80°C
  • Heater temperature setting: Maximum
  • Blower fan: ON
  • 12 seconds later after the engine has start up

 1 V or lower
Other than the above
 System voltage
49
 No. 1 intake air temperature sensor
 Ignition switch: ON
 Intake air temperature: -20 °C
 4.0 - 4.6 V
Intake air temperature: 0 °C
 3.1 - 3.7 V
Intake air temperature: 20 °C
 2.1 - 2.7 V
Intake air temperature: 40 °C
 1.2 - 1.8 V
Intake air temperature: 60 °C
 0.6 - 1.2 V
Intake air temperature: 80 °C
 0.2 - 0.8 V
50
 Air flow sensor
 Engine: Gradually increase the speed
 Voltage increase
51
 Exhaust gas recirculation position sensor
 Engine: Idling (after warning up)
 2.0 V or higher
Engine: 3,500 r/min (after warning up)
 1.5 V or lower
52
 Manifold absolute pressure sensor
 Ignition switch: ON
 0.7 - 1.2 V
Engine: Acceleration
 Increases
53
 Engine coolant temperature sensor
 Ignition switch: ON
 Engine coolant temperature: -20 °C
 4.4 - 4.9 V
Engine coolant temperature: 0 °C
 4.4 - 4.6 V
Engine coolant temperature: 20 °C
 3.3 - 3.9 V
Engine coolant temperature: 40 °C
 2.4 - 3.0 V
Engine coolant temperature: 60 °C
 1.5 - 2.1 V
Engine coolant temperature: 80 °C
 0.9 - 1.5 V
54
 Fuel temperature sensor
 Ignition switch: ON
 Fuel temperature: -20 °C
 3.9 - 4.5 V
Fuel temperature: 0 °C
 3.1 - 3.7 V
Fuel temperature: 20 °C
 2.1 - 2.7 V
Fuel temperature: 40 °C
 1.2 - 1.8 V
Fuel temperature: 60 °C
 0.6 - 1.2 V
Fuel temperature: 80 °C
 0.2 - 0.8 V
56
 Rail pressure sensor
 Engine: Idling (after warning up)
 1.15 - 1.75 V
57
 Camshaft position sensor
 Engine: Cranking
 0.1 - 3.0* V
Engine: Idling
 0.5 - 1.5* V
58
 Crank angle sensor
 Engine: Cranking
 1.5 - 4.5* V
Engine: Idling
 2.5 - 3.5* V
59
 Camshaft position sensor power supply
 Ignition switch: ON
 4.9 - 5.1 V
60
 Crank angle sensor power supply
 Ignition switch: ON
 4.9 - 5.1 V
65
 No. 2 intake air temperature sensor
 Ignition switch: ON
 Intake air temperature: -20 °C
 4.0 - 4.6 V
Intake air temperature: 0 °C
 3.1 - 3.7 V
Intake air temperature: 20 °C
 2.1 - 2.7 V
Intake air temperature: 40 °C
 1.2 - 1.8 V
Intake air temperature: 60 °C
 0.6 - 1.2 V
Intake air temperature: 80 °C
 0.3 - 0.9 V
80
 Sensor source
 Ignition switch: ON
 4.9 - 5.1 V
81
 Rail pressure sensor power supply
 Ignition switch: ON
 4.9 - 5.1 V
92
 Ignition switch-IG
 Ignition switch: ON
 System voltage
96
 Power steering switch
 Engine: Idling
 When steering wheel is stationary
 System voltage
When steering wheel is turned
 1.0 V or lower
99
 Battery
 Ignition switch: ON
 System voltage
100
101
 Battery (backup with monitor)
 Ignition switch: ON
 System voltage
102
 Fuel filter pressure switch
 Ignition switch: ON
 System voltage

  • Engine: Idling
  • Squeeze the fuel hose with one’s fingers at the inlet side of fuel filter

 1 V or lower
103
 Ignition switch-ST
 Engine: Cranking
 System voltage
104
 First and second shift switch <M/T>
 Ignition switch: ON
 Shift position: 1st and 2nd
 System voltage
Shift position: Except 1st and 2nd
 1 V or lower
105
 Back-up lamp shift switch <M/T>
 Ignition switch: ON
 Shift position: Reverse
 System voltage
Shift position: Except reverse
 1 V or lower
109
 Engine control relay
 Ignition switch: LOCK (OFF)
 System voltage
Ignition switch: ON
 1 V or lower
111
 Throttle valve control servo (-)
 Engine: Stopped from idling speed
 Voltage changed for few seconds
112
 Accelerator pedal position sensor (sub) power supply
 Ignition switch: ON
 4.9 - 5.1 V
113
 Accelerator pedal position sensor (sub)
 Ignition switch: ON
 Release the accelerator pedal
 0.2 - 0.8 V
Depress the accelerator pedal fully
 2.0 V or higher
119
 Vehicle speed sensor
  • Ignition switch: ON
  • Move the vehicle forward slowly

 0 <=> 5 V Changes repeatedly
120
 Accelerator pedal position sensor (main) power supply
 Ignition switch: ON
 4.9 - 5.1 V
121
 Accelerator pedal position sensor (main)
 Ignition switch: ON
 Release the accelerator pedal
 0.7 - 1.3 V
Depress the accelerator pedal fully
 4.0 V or higher
124
 Throttle position sensor
  • Remove the intake air hose at the throttle body
  • Disconnect the connector of the electronic-controlled throttle valve
  • With the special tool test harness (MB991658) bridge only the mating terminals of No. 1, No. 2, and No. 4 of the disconnected connectors
  • Ignition switch: ON (engine stopped)

 Fully close the throttle valve with your finger
 0.3 - 0.7 V
Fully open the throttle valve with your finger
 4.0 V or higher
130
 Throttle valve control servo (+)
 Engine: Stopped from idling speed
 Voltage changed for few seconds
note *:The average voltage is shown when an analog voltmeter is used (because the average voltage might not be shown stably when digital voltmeter is used).
Engine-ECU Connector Terminal Arrangement

CHECK CHART FOR RESISTANCE AND CONTINUITY BETWEEN TERMINALS
1.Turn the ignition switch to "LOCK" (OFF) position.
2.Disconnect the engine-ECU connector.
3.Measure the resistance and check for continuity between the terminals of the engine-ECU harness-side connector while referring to the check chart.
note
  1. When measuring resistance and checking continuity, a harness for checking contact pin pressure should be used instead of inserting a test probe.
  2. Checking need not be carried out in the order given in the chart.
caution If the terminals that should be checked are mistaken, or if connector terminals are not correctly shorted to earth, damage may be caused to the vehicle wiring, sensors, engine-ECU and/or ohmmeter. Be careful to prevent this!
4.If the ohmmeter shows any deviation from the standard value, check the corresponding sensor, actuator and related electrical wiring, and the repair or replace.
5.After repair or replacement, recheck with the ohmmeter to confirm that the repair or replacement has corrected the problem.
Engine-ECU Harness Side Connector Terminal Arrangement
Terminal No.
 Inspection item
 Normal condition (Check condition)
17 - 37
 Suction control valve
 Approximately 2.1 Ω (at 20°C)
22 - Body earth
 Engine-ECU earth
 Continuity (2 Ω or less)
61 - Body earth
49 - 70
 No. 1 intake air temperature sensor
 13 - 17 kΩ (when the intake air temperature is -20°C)
5.4 - 6.6 kΩ (when the intake air temperature is 0°C)
2.3 - 3.0 kΩ (when the intake air temperature is 20°C)
1.0 - 1.5 kΩ (when the intake air temperature is 40°C)
0.56 - 0.76 kΩ (when the intake air temperature is 60°C)
0.31 - 0.43 kΩ (when the intake air temperature is 80°C)
53 - 74
 Engine coolant temperature sensor
 14 - 17 kΩ (when the engine coolant temperature is -20°C)
5.1 - 6.5 kΩ (when the engine coolant temperature is 0°C)
2.1 - 2.7 kΩ (when the engine coolant temperature is 20°C)
0.9 - 1.3 kΩ (when the engine coolant temperature is 40°C)
0.48 - 0.68 kΩ (when the engine coolant temperature is 60°C)
0.26 - 0.36 kΩ (when the engine coolant temperature is 80°C)
54 - 75
 Fuel temperature sensor
 2.0 - 3.0 kΩ (at 20 °C)
65 - 75
 No. 2 intake air temperature sensor
 13 - 18 kΩ (when the intake air temperature is -20°C)
5.1 - 6.9 kΩ (when the intake air temperature is 0°C)
2.0 - 3.0 kΩ (when the intake air temperature is 20°C)
0.9 - 1.5 kΩ (when the intake air temperature is 40°C)
0.40 - 0.78 kΩ (when the intake air temperature is 60°C)
0.23 - 0.42 kΩ (when the intake air temperature is 80°C)
111 - 130
 Throttle valve control servo
 0.3 - 100 Ω (at 20 °C)