CHECK AT THE ECU TERMINALS


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 <M/T> or engine-A/T-ECU <A/T> 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 <M/T> or engine-A/T-ECU <A/T> connector connected.
  2. You may find it convenient to pull out the engine-ECU <M/T> or engine-A/T-ECU <A/T> to make it easier to reach the connector terminals.
  3. The chart procedures do not have the particular order.
caution Short-circuiting the positive (+) probe between a connector terminal and earth could damage the vehicle wiring, the sensor, engine-ECU <M/T> or engine-A/T-ECU <A/T> 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
 Check condition (Engine condition)
 Normal condition
1
 No. 1 injector
 While engine is idling after having warmed up, suddenly depress the accelerator pedal.
 From 11 - 14 V*, momentarily drops slightly
5
 No. 2 injector
14
 No. 3 injector
21
 No. 4 injector
2
 No. 5 injector
6
 No. 6 injector
8
 A/C compressor relay

  • Engine: Idle speed
  • A/C switch: OFF → ON (A/C compressor is operating)

 System voltage → 1 V or less
10
 Left bank oxygen sensor (front) heater
 Engine: Idling after warming up
 9 - 11 V
Under the high load operation
 From 9 - 11 V momentarily changes to system voltage
15
 Throttle valve control servo relay
 Ignition switch: OFF
 System voltage
Ignition switch: ON
 1 V or less
16
 Fuel pump relay
Ignition switch: ON
 System voltage
Engine: Idle speed
 1 V or less
17
 A/C condenser fan relay
 Fan is not operating
 System voltage
Fan is operating
 0 - 3 V
18
 Left bank oxygen sensor (rear) heater
 Engine: Idling after warming up
 9 - 11 V
Under the high load operation
 From 9 - 11 V momentarily changes to system voltage
23
 Purge control solenoid valve
 Ignition switch: ON
 System voltage
Running at 3,000 r/min while engine is warming up after having been started.
 Decreases voltage
24
 Right bank oxygen sensor (rear) heater
 Engine: Idling after warming up
 9 - 11 V
Under the high load operation
 From 9 - 11 V momentarily changes to system voltage
25
 Right bank oxygen sensor (front) heater
 Engine: Idling after warming up
 9 - 11 V
Under the high load operation
 From 9 - 11 V momentarily changes to system voltage
31
 Ignition coil - No. 1
 Engine: 3,000 r/min
 0.3 - 3.0 V*
35
 Ignition coil - No. 2
44
 Ignition coil - No. 3
52
 Ignition coil - No. 4
32
 Ignition coil - No. 5
36
 Ignition coil - No. 6
34
 Power supply
 Ignition switch: ON
 System voltage
43
39
 Brake lamp switch
 Depress the brake pedal
 System voltage
Release the brake pedal
 1 V or less
45
 Alternator G terminal
  • Engine: Warm, idle (radiator fan: OFF)
  • Headlamp: OFF → ON
  • Stop lamp: OFF → ON
  • Rear defogger switch: OFF → ON

 Voltage increases
47
 Power steering fluid pressure switch
 Engine: Idling after warming up
 When steering wheel is Stationary
 System voltage
When steering wheel is turned
 1 V or less
50
 Ignition switch - IG
 Ignition switch: ON
 System voltage
51
 Ignition switch - ST
 Engine: Cranking
 8 V or more
57
 Engine control relay
Ignition switch: "LOCK" (OFF)
 System voltage
Ignition switch: ON
 1 V or less
58
 Backup power supply
 Ignition switch: "LOCK" (OFF)
 System voltage
63
 Air flow sensor
 Gradually increase the engine speed.
 Voltage increase in response to revving
69
 A/C switch
 Engine: Idling after warming up
 A/C switch: OFF
 1 V or less
A/C switch: ON (A/C compressor is operating)
 System voltage
70
 Crank angle sensor
 Engine: Cranking
 0.4 - 4.0 V
Engine: Idling
 1.5 - 2.5 V
71
 Camshaft position sensor
 Engine: Cranking
 0.4 - 3.0 V
Engine: Idling
 0.5 - 2.0 V
78
 A/C load signal
  • Engine: Idling after warming up
  • A/C switch: ON (A/C compressor is operating)

 When the A/C is operating under low load
 1 V or less
When the A/C is operating under high load
 System voltage
79
Vehicle speed sensor
  • Ignition switch: "ON"
  • Move the vehicle forward slowly

 0 <=> 8 - 12 V Changes repeatedly
86
 Alternator FR terminal
  • Engine: Warm, idle (radiator fan: OFF)
  • Headlamp: OFF → ON
  • Stop lamp: OFF → ON
  • Rear defogger switch: OFF → ON

 Voltage decreases
87
 Tachometer signal
 Engine: 3,000 r/min
 0.3 - 3.0 V
92
 Power supply voltage applied to accelerator pedal position sensor (main)
 Ignition switch: "ON"
 4.9 - 5.1 V
97
 Sensor impressed voltage
 Ignition switch: ON
 4.9 - 5.1 V
98
 Engine coolant temperature sensor
 Ignition switch: ON
 When engine coolant temperature is -20°C
 3.9 - 4.5 V
When engine coolant temperature is 0°C
 3.2 - 3.8 V
When engine coolant temperature is 20°C
 2.3 - 2.9 V
When engine coolant temperature is 40°C
 1.3 - 1.9 V
When engine coolant temperature is 60°C
 0.7 - 1.3 V
When engine coolant temperature is 80°C
 0.3 - 0.9 V
99
 Intake air temperature sensor
 Ignition switch: ON
 When intake air temperature is -20°C
 3.8 - 4.4 V
When intake air temperature is 0°C
 3.2 - 3.8 V
When intake air temperature is 20°C
 2.3 - 2.9 V
When intake air temperature is 40°C
 1.5 - 2.1 V
When intake air temperature is 60°C
 0.8 - 1.4 V
When intake air temperature is 80°C
 0.4 - 1.0 V
101
 Manifold absolute pressure sensor
 Ignition switch: ON
 At 0 m altitude
 3.8 - 4.2 V
At 600 m altitude
 3.5 - 3.9 V
At 1,200 m altitude
 3.3 - 3.7 V
At 1,800 m altitude
 3.0 - 3.4 V
Engine: Idle operation after warm-up
 0.8 - 2.4 V
Engine: While the engine is idling after warm-up, quickly depress the accelerator pedal
 Varies depending on the negative pressure at the inlet manifold
102
 Power supply voltage applied to accelerator pedal position sensor (sub)
 Ignition switch: ON
 4.9 - 5.1 V
106
 Power supply voltage applied to throttle position sensor
 Ignition switch: ON
 System voltage
107
 Accelerator pedal position sensor (sub)
 Ignition switch: ON
 Release the accelerator pedal
 0.3 - 0.7 V
Depress the accelerator pedal fully
 1.9 - 2.5 V
108
 Left bank oxygen sensor (front)
 Engine: Running at 2,500 r/min after warmed up
 0 V <=> 0.8 V (Changes repeatedly)
109
 Right bank oxygen sensor (front)
 Engine: Running at 2,500 r/min after warmed up
0 V <=> 0.8 V (Changes repeatedly)
113
 Throttle position sensor (sub)
  • Remove the intake air hose at the throttle body
  • Disconnect the throttle position sensor, and then connect terminal numbers No. 1, No. 2, No. 3 and No. 4 with the use of the special tool (MB991658).
  • Ignition switch: ON

 Fully close the throttle valve with your finger
 4.3 - 4.7 V
Fully open the throttle valve with your finger
 0.2 - 1.1 V
114
 Accelerator pedal position sensor (main)
 Ignition switch: ON
 Release the accelerator pedal
 0.8 - 1.2 V
Depress the accelerator pedal fully
 4.0 - 4.8 V
115
 Throttle position sensor (main)
  • Remove the intake air hose at the throttle body
  • Disconnect the throttle position sensor, and then connect terminal numbers No. 1, No. 2, No. 3 and No. 4 with the use of the special tool (MB991658).
  • Ignition switch: "ON"

 Fully close the throttle valve with your finger
 0.3 - 0.7 V
Fully open the throttle valve with your finger
 3.9 - 4.8 V
116
 Left bank oxygen sensor (rear)
  • Transmission: 2nd
  • The engine speed is maintained to 3,500 r/ min or more during an accelerated driving with the throttle full-open

 0.6 - 1.0 V
117
 Right bank oxygen sensor (rear)
  • Transmission: 2nd
  • The engine speed is maintained to 3,500 r/ min or more during an accelerated driving with the throttle full-open

 0.6 - 1.0 V
132
 Power supply voltage applied to throttle valve control servo
 Ignition switch: ON
 System voltage
133
 Throttle valve control servo (+)
  • Ignition switch: ON
  • Accelerator pedal: fully opened → fully closed

 Decreases slightly (approximately 2 V) from battery voltage.
141
 Throttle valve control servo (-)
  • Ignition switch: ON
  • Accelerator pedal: fully closed → fully opened

 Decreases slightly (approximately 2 V) from battery voltage.
Engine-ECU <M/T> or engine-A/T-ECU <A/T> 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 <M/T> or engine-A/T-ECU <A/T> connector.
3.Measure the resistance and check for continuity between the terminals of the engine-ECU <M/T> or engine-A/T-ECU <A/T> 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. The chart procedures do not have the particular order.
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 <M/T> or engine-A/T-ECU <A/T> 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 <M/T> or engine-A/T-ECU <A/T> Harness Side Connector Terminal Arrangement
Terminal No.
 Inspection item
 Normal condition (Check condition)
1 - 34
 No. 1 injector
 10.5 - 13.5 Ω (at 20°C)
5 - 34
 No. 2 injector
14 - 34
 No. 3 injector
21 - 34
 No. 4 injector
2 - 34
 No. 5 injector
6 - 34
 No. 6 injector
10 - 34
 Left bank oxygen sensor (front) heater
 4.5 - 8.0 Ω (at 20°C)
25 - 34
 Right bank oxygen sensor (front) heater
18 - 34
 Left bank oxygen sensor (rear) heater
 11 - 18 Ω (at 20°C)
24 - 34
 Right bank oxygen sensor (rear) heater
23 - 34
 Purge control solenoid valve
 22 - 26 Ω (at 20°C)
33 - Body earth
 ECU earth
 Continuity (2 Ω or less)
42 - Body earth
96 - 98
 Engine coolant temperature sensor
 14 - 17 kΩ (When coolant temperature is -20°C)
5.1 - 6.5 kΩ (When coolant temperature is 0°C)
2.1 - 2.7 kΩ (When coolant temperature is 20°C)
0.9 - 1.3 kΩ (When coolant temperature is 40°C)
0.48 - 0.68 kΩ (When coolant temperature is 60°C)
0.26 - 0.36 kΩ (When coolant temperature is 80°C)
96 - 99
 Intake air temperature sensor
 13 - 17 kΩ (When intake air temperature is -20°C)
5.4 - 6.6 kΩ (When intake air temperature is 0°C)
2.3 - 3.0 kΩ (When intake air temperature is 20°C)
1.0 - 1.5 kΩ (When intake air temperature is 40°C)
0.56 - 0.76 kΩ (When intake air temperature is 60°C)
0.31 - 0.43 kΩ (When intake air temperature is 80°C)
133 - 141
 Throttle actuator control motor
 0.3 - 100 Ω (at 20°C)