CHECK AT THE ECU TERMINALS


1.Disconnect the engine-ECU connectors A-08 and A-09, and connect check harness special tool MB991987 between the engine-ECU connectors.
2.Measure the voltage between each check harness connector terminal and check harness connector earth terminal (No. 75 or No. 76).
3.Connect a needle-nosed wire probe to a voltmeter probe.
4.Referring to the check sheet, insert the micromini probe into the check harness connector and measure the voltage.
note
  1. You may find it convenient to pull out the engine-ECU to make it easier to reach the connector terminals.
  2. 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!
5.If voltmeter shows any division from standard value, check the corresponding sensor, actuator and related electrical wiring, then repair or replace.
6.After repair or replacement, recheck with the voltmeter to confirm that the repair has corrected the problem.

TERMINAL VOLTAGE CHECK CHART




Terminal No.
 Check item
 Check condition (Engine condition)
 Normal condition
7
 Throttle valve control servo (+)
  • Ignition switch: "ON"
  • Accelerator pedal: fully opened → fully closed

 Decreased slightly (approximately 2 V) from battery voltage.
8
 No. 1 injector
 While engine is idling after having warmed up, suddenly depress the accelerator pedal.
 From 9 - 13 V*1, momentarily drops slightly
9
 No. 2 injector
23
 No. 3 injector
10
 Ignition coil - No. 1
 Engine: 3,000 r/min
 0.3 - 3.0 V*1
25
 Ignition coil - No. 2
40
 Ignition coil - No. 3
11
 Neutral position sensor <Vehicles with AS&G system>
 Ignition switch: "ON"
 Transmission: Neutral
 2.0 - 3.0 V*1
Transmission: 1st, 3rd, 5th
 3.0 V*1or more
Transmission: 2nd, 4th, Reverse
 2.0 V*1 or less
12
 Camshaft position sensor
 Engine: Cranking
 2.0 - 4.8 V*1
Engine: Idling
 3.0 - 4.0 V*1
13
 Crank angle sensor
 Engine: Cranking
 0.4 - 4.0 V*1
Engine: Idling
 2.0 - 3.0 V*1
14
 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
15
 Throttle position sensor (main)
  • Remove the intake air hose at the throttle body
  • Disconnect the throttle position sensor, and then connect terminal numbers No. 3, No. 4, No. 5 and No. 6 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
 4.0 V or more
16
 Throttle position sensor (sub)
  • Remove the intake air hose at the throttle body
  • Disconnect the throttle position sensor, and then connect terminal numbers No. 3, No. 4, No. 5 and No. 6 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 - 0.6 V
17
 Manifold absolute pressure sensor
 Ignition switch: "ON"
 Altitude: 0 m
 3.9 - 4.3 V
Altitude: 600 m
 3.6 - 4.0 V
Altitude: 1,200 m
 3.4 - 3.8 V
Altitude: 1,800 m
 3.1 - 3.5 V
Engine: warming up, idling
 0.9 - 1.3 V

  • Engine: Idling.
  • Revving (momentary wide open throttle)

 The voltage in accordance with the vacuum pressure in the inlet manifold.
22
 Throttle valve control servo (-)
  • Ignition switch: "ON"
  • Accelerator pedal: fully closed → fully opened

 Decreases slightly (approximately 2 V) from battery voltage.
31
 Power supply voltage applied to throttle position sensor
 Ignition switch: "ON"
 4.9 - 5.1 V
32
 Manifold absolute pressure sensor impressed voltage
 Ignition switch: "ON"
 4.9 - 5.1 V
38
 Purge control solenoid valve
 Ignition switch: "ON"
 System voltage
Engine: warming up within 3 minutes, 2000 r/min or more
 Decreased voltage
41
 Power supply voltage applied to neutral position sensor <Vehicles with AS&G system>
 Ignition switch: "ON"
 4.9 - 5.1 V
50
 Oil pressure switch
 Ignition switch: "ON"
 0.5 V or less
Engine: Idling after warming up
 System voltage
51
 Alternator L terminal
 Ignition switch: "ON"
 0.5 - 2.0 V
Engine: Idling
 System voltage
53
 Alternator G terminal
  • Engine: Warm, idle (radiator fan: OFF)
  • Headlamp: OFF → ON
  • Stop lamp: OFF → ON
  • Rear defogger switch: OFF → ON

 Increased voltage
54
 Alternator FR terminal
  • Engine: Warm, idle (radiator fan: OFF)
  • Headlamp: OFF → ON
  • Stop lamp: OFF → ON
  • Rear defogger switch: OFF → ON

 Decreased voltage
56
 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
77
 Power supply
 Ignition switch: "ON"
 System voltage
92
78
 Power supply voltage applied to throttle valve control servo
 Ignition switch: "ON"
 System voltage
79
 Oxygen sensor heater (front)
  • Engine: Warming up
  • Immediately after the engine start

 Voltage change
Engine: 4,000 r/min
 System voltage
80
 Ignition switch - ST
 Engine: Cranking
 8 V or more
81
 Fuel pump relay
Ignition switch: ON
 System voltage
Engine: Idle speed
 1 V or less
82
 Backup power supply
 Ignition switch: "ON"
 System voltage
83
 Accelerator pedal position sensor (main)
 Ignition switch: "ON"
 Release the accelerator pedal
 0.9 - 1.1 V
Depress the accelerator pedal fully
 3.0 V or more
85
 Power supply voltage applied to accelerator pedal position sensor (main)
 Ignition switch: "ON"
 4.9 - 5.1 V
86
 Power supply voltage applied to accelerator pedal position sensor (sub)
 Ignition switch: "ON"
 2.4 - 2.6 V
88
 Accelerator pedal position sensor (sub)
 Ignition switch: "ON"
 Release the accelerator pedal
 0.4 - 0.6 V
Depress the accelerator pedal fully
 1.5 V or more
90
 Hood buzzer switch <Vehicles with AS&G system>
 Ignition switch: "ON"
 Hood: Close
 System voltage
Hood: Open
 1 V or less
91
 Auto stop & go (AS&G) OFF switch <Vehicles with AS&G system>
 Ignition switch: "ON"
 AS&G OFF switch: ON
 1 V or less
AS&G OFF switch: OFF
 System voltage
94
 Oxygen sensor heater (rear)
  • Engine: Warming up
  • Immediately after the engine start

 Voltage change
Engine: 5,000 r/min
 System voltage
95
 A/C compressor relay
  • Engine: Idling
  • A/C switch: OFF → ON
    (when the compressor is active)

 Battery voltage → 1 V or less
97
 Oxygen sensor (front)
 Engine: Running at 2,500 r/min after warmed up (Check using a digital type voltmeter)
 0 <=> 0.8 V (Changes repeatedly)
100
 Oxygen sensor (rear)
 Engine: After warm-up
 At excessive acceleration
 0 <=> 0.6 V (Changes repeatedly)
101
 Clutch switch (B) <Vehicles with AS&G system>
 Ignition switch: "ON"
 Clutch pedal: Fully depressed
 System voltage
Clutch pedal: Released
 1 V or less
107
 Engine control relay
 Ignition switch: "LOCK" (OFF)
 System voltage
Ignition switch: "ON"
 1 V or less
110
 Power supply voltage applied to battery current sensor <Vehicles with AS&G system>
 Ignition switch: "ON"
 4.9 - 5.1 V
111
 Battery current sensor <Vehicles with AS&G system>
 The battery is being discharged.

  • Engine: Cranking
 The value changes by the value less than 3.5 V.
The battery is being charged.

  • Leave the ignition switch being in the ON position for seferal minutes, and then after the engine start.
 The value gradually increases from the value more than 3.5 V*2
113
 Clutch switch (A) <Vehicles with AS&G system>
 Ignition switch: "ON"
 Clutch pedal: Depressed
 1 V or less
Clutch pedal: Released
 System voltage
115
 Starter cut relay monitor <Vehicles with AS&G system>
 Ignition switch: "ON"
 1 V or less
Engine: Cranking
 System voltage
116
 Starter cut relay <Vehicles with AS&G system>
 Ignition switch: "ON"
 System voltage
Engine: Cranking
 1 V or less
120
 Starter active signal <Vehicles with AS&G system>
 Engine: Cranking
 System voltage
Engine: Idle operation
 1 V or less
122
 Ignition switch - IG
 Ignition switch: "ON"
 System voltage
123
 Throttle valve control servo relay
 Ignition switch: "LOCK" (OFF)
 0 - 0.1 V
Ignition switch: "ON"
 1 V or less
125
 Starter relay <Vehicles without AS&G system>
 Ignition switch: "ON"
 System voltage
Engine: Cranking
 1 V or less
Engine: Idling
 System voltage
Starter control relay <Vehicles with AS&G system>
 Ignition switch: "ON"
 1 V or less
Engine: Cranking
 System voltage
127
 Power supply voltage applied to brake vacuum sensor <Vehicles with AS&G system>
 Ignition switch: "ON"
 4.9 - 5.1 V
128
 Brake vacuum sensor <Vehicles with AS&G system>
 Engine: warming up, idle
 Turn the ignition switch ON after the engine stops from the idling. Depress the brake pedal several times.
 The voltage is reduced according to the brake depressing amount.
131
 Battery temperature sensor <Vehicles with AS&G system>
 Ignition switch: "ON"
 When battery temperature sensor ambient air temperature is -20°C
 3.9 - 4.5 V
When battery temperature sensor ambient air temperature is 0°C
 3.2 - 3.8 V
When battery temperature sensor ambient air temperature is 20°C
 2.3 - 2.9 V
When battery temperature sensor ambient air temperature is 40°C
 1.4 - 2.0 V
When battery temperature sensor ambient air temperature is 60°C
 0.7 - 1.3 V
When battery temperature sensor ambient air temperature is 80°C
 0.3 - 0.9 V
135
 Capacitor relay <Vehicles with AS&G system>
 Adjust the engine with the following conditions to achieve the auto stop status.

  • Engine: Idle operation (3 minutes after starting engine)
  • Engine coolant temperature: 85 - 95°C
  • Lamps, electric cooling fan and all accessories: OFF
  • Auto Stop & Go (AS&G) OFF switch: ON
  • Hood: Close
  • Fasten the driver’s seat belt
  • Stop the vehicle after driving at 5 km/h or more. Place the transmission in the neutral position.
  • Clutch pedal: Released
 Clutch pedal: Depressed (this allows the engine to achieve the auto start status.)
 System voltage → The voltage is instantly reduced.
note *1: 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).
note *2: If the battery is fully charged, the output reading may be incorrect.

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.


Terminal No.
 Inspection item
 Normal condition (Check condition)
7 - 22
 Throttle valve control servo
 0.3 - 80 Ω (at 20°C)
8 - 77
 No. 1 injector
 14 - 15 Ω (at 20°C) <134>
10.5 - 13.5 Ω (at 20°C) <3A9>
9 - 77
 No. 2 injector
23 - 77
 No. 3 injector
14 - 29
 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)
33 - 56
 Intake air temperature sensor
 13 - 17 kΩ (When intake air temperature is -20°C)
5.3 - 6.7 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)
0.30 - 0.42 kΩ (When intake air temperature is 80°C)
38 - 77
 Purge control solenoid valve
 30 - 34 Ω (at 20°C)
75 - Body earth
 ECU earth
 Continuity (2 Ω or less)
76 - Body earth
93 - Body earth
108 - Body earth
77 - 79
 Oxygen sensor heater (front)
 5 - 30 Ω (at 20°C)
77 - 94
 Oxygen sensor heater (rear)
 5 - 30 Ω (at 20°C)
84 - 85
 Accelerator pedal position sensor (main)
 1.1 - 2.4 kΩ (at 20°C)
86 - 87
 Accelerator pedal position sensor (sub)
 0.8 - 1.7 kΩ (at 20°C)
112 - 113
 Battery temperature sensor <Vehicles with AS&G system>
 4.9 - 5.3 kΩ (When in battery temperature sensor ambient air temperature is 0°C)
2.2 - 2.6 kΩ (When in battery temperature sensor ambient air temperature is 20°C)
1.0 - 1.4 kΩ (When in battery temperature sensor ambient air temperature is 40°C)