CHECK AT THE ECU TERMINALS


TERMINAL VOLTAGE CHECK CHART
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.
1.Disconnect the engine-ECU connectors, and connect check harness special tool MB992291 between the engine-ECU connectors.
2.Measure the voltage between each check harness connector terminal and check harness connector earth terminal (GNDB, GNDE or SGND).
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 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 or all of them. Be careful to prevent this!
5.If voltmeter shows any deviation 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.
Engine-ECU Connector Terminal Arrangement
Terminal No.
 Terminal code
 Check item
 Inspection condition (engine status)
 Normal condition:
6
 NTSW
 Starter active signal
 Engine: Cranking
 System voltage
Engine: Idle operation
 1 V or less
7
 AC/S
 A/C switch signal <Cooler, Manual A/C>
 Engine: Idle speed (after warning up)
  • A/C switch: OFF <Manual A/C>
  • Blower switch: OFF <Cooler>

 System voltage

  • Blower switch: Other than OFF
  • A/C switch: ON <Manual A/C>
  • Dual pressure switch: ON state

 1 V or less
8
 ALTL
 Alternator L terminal
 Ignition switch: ON
 0.5 - 2.0 V
Engine: Idle operation
 System voltage
9
 BFAN
 Blower fan switch <Cooler, Manual A/C>
 Engine: Idle speed (after warning up)
 Blower fan switch: OFF
 System voltage
Blower fan switch mode: 3
 1 V or less
10
 WLS
 Water level switch
 Ignition switch: ON
 Water level in the fuel filter: Lower than the standard value (approximately 130 ml or less)
 1 V or less
Water level in the fuel filter: Higher than the standard value (approximately 130 ml or more)
 System voltage
11
 FFPS
 Fuel filter pressure switch
 Engine: Idling (after warning up)
 System voltage

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

 1 V or less
13
 P/S
 Power steering fluid pressure switch
 Engine: Idling
 When steering wheel is stationary
 System voltage
When steering wheel is turned
 1.0 V or less
18
 STRL
 Starter relay
 Engine: Cranking
 System voltage
Engine: Idle operation
 1 V or less
19
 AC/R
 A/C compressor relay
 Engine: Idle speed (after warning up)
 A/C switch: OFF <Manual A/C>
Blower switch: OFF <Cooler>
 System voltage

  • Blower switch: Other than OFF
  • A/C switch: ON <Manual A/C>
  • A/C compressor in operation

 1 V or less
20
 GLOW
 Glow plug relay
 Ignition switch: OFF → ON
 Engine coolant temperature: lower than 60 °C
 1 V or less → System voltage (after several seconds have elapsed)
Engine coolant temperature: higher than 60 °C
 System voltage
21
 F/LO
 Condenser fan relay <Vehicles with A/C condenser fan>
 Engine: Idling after warming up the engine
 A/C switch: OFF <Manual A/C>
Blower switch: OFF <Cooler>
 System voltage

  • Blower switch: Other than OFF
  • A/C switch: ON <Manual A/C>
  • A/C compressor in operation

 1 V or less <=> System voltage (Changes repeatedly)
37
 MAP
 Manifold absolute pressure sensor
 Ignition switch: ON
 0.4 - 2.2 V
Engine: Acceleration
 Increases
38
 ATS2
 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
40
 TPSM
 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 more
42
 OPSW
 Engine oil pressure switch
 Ignition switch: ON
 1 V or less
Engine: Idle operation
 System voltage
55
 FTS
 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
57
 EGRP
 EGR valve position sensor
 Engine: Idling (after warning up)
 2.0 V or more
Engine: 3,500 r/min (after warning up)
 1.5 V or less
61
 AC/T
 A/C fin thermo sensor
 Evaporator surface temperature: 25°C (1.5 kΩ)
 1.1 - 1.3 V
63
 WTS
 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
64
 FPS
 Rail pressure sensor
 Engine: Idling (after warning up)
 1.15 - 1.75 V
66
 SGC
 Camshaft position sensor
 Engine: Cranking
 0.1 - 3.0 V*
Engine: Idling
 0.5 - 1.5 V*
67
 SGT
 Crank angle sensor
 Engine: Cranking
 1.5 - 4.5 V*
Engine: Idling
 2.5 - 3.5 V*
68
 SGTB
 Power supply voltage applied to crank angle sensor
 Ignition switch: ON
 4.9 - 5.1 V
69
 5V
 Power supply voltage applied to camshaft position sensor
 Ignition switch: ON
 4.9 - 5.1 V
70
 FPS5
 Power supply voltage applied to rail pressure sensor
 Ignition switch: ON
 4.9 - 5.1 V
71
 EGR5
 Power supply voltage applied to EGR valve position sensor
 Ignition switch: ON
 4.9 - 5.1 V
72
 MAP5
 Power supply voltage applied to manifold absolute pressure sensor
 Ignition switch: ON
 4.9 - 5.1 V
93
 TPS5
 Power supply voltage applied to throttle position sensor
 Ignition switch: ON
 4.9 - 5.1 V
101
 BAT1
 Power supply
 Ignition switch: ON
 System voltage
102
 BAT2
103
 BACK
 Backup power supply
 Ignition switch: "LOCK" (OFF)
 System voltage
104
 IGN
 Ignition switch-IG
 Ignition switch: ON
 System voltage
110
 BRK
 Brake switch
 Ignition switch: ON
 Depress the brake pedal
 1V or less
Release the brake pedal
 System voltage
111
 ST
 Ignition switch-ST
 Engine: Cranking
 System voltage
112
 CLT1
 Clutch switch <M/T>
 Ignition switch: ON
 Depress the clutch pedal
 System voltage
Release the clutch pedal
 1V or less
114
 ETV+
 Throttle valve control servo (+)
 Engine: Stopped from idling speed
 Voltage changed for few seconds
115
 EGR+
 EGR valve (+)
 Engine: Idling (after warning up)
 1 - 3 V*
Engine: 3,500 r/min (after warning up)
 1.0 V or less
118
 C/R
 Engine control relay
 Ignition switch: "LOCK" (OFF)
 System voltage
Ignition switch: ON
 1 V or less
131
 SCV+
 Suction control valve (+)
 Engine: Idling
 5 - 6 V*
Engine: Acceleration
 Decreases
134
 AP5
 Accelerator pedal position sensor (sub) power supply
 Ignition switch: ON
 4.9 - 5.1 V
135
 APSS
 Accelerator pedal position sensor (sub)
 Ignition switch: ON
 Release the accelerator pedal
 0.4 - 0.6 V
Depress the accelerator pedal fully
 2.0 V or more
140
 AFS
 Air flow sensor
 Engine: Gradually increase the speed
 Voltage increase
149
 APS5
 Accelerator pedal position sensor (main) power supply
 Ignition switch: ON
 4.9 - 5.1 V
150
 APSM
 Accelerator pedal position sensor (main)
 Ignition switch: ON
 Release the accelerator pedal
 0.9 - 1.1 V
Depress the accelerator pedal fully
 4.0 V or more
note *: The average voltage is shown when an analogue voltmeter is used (because the average voltage might not be shown stably when digital voltmeter is used).

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. 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 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.
 Terminal code
 Inspection item
 Normal condition (Check condition)
1 - 2
 I/B1 - INJ1
 No. 1 injector
 Approximately 0.45 Ω (at 20°C)
25 - 75
 I/B2 - INJ2
 No. 2 injector
25 - 50
 I/B2 - INJ3
 No. 3 injector
1 - 27
 I/B1 - INJ4
 No. 4 injector
32 - 38
 AT2E - ATS2
 Intake air temperature sensor
 13 - 18 kΩ (at -20°C)
5.1 - 6.9 kΩ (at 0°C)
2.0 - 3.0 kΩ (at 20°C)
[0.9 - 1.5 kΩ (at 40°C)]
[0.40 - 0.78 kΩ (at 60°C)]
0.23 - 0.42 kΩ (at 80°C)
47 - Body earth
 TH - Body earth
 Throttle solenoid valve
 29 - 35 kΩ (at 20 °C)
55 - 79
 FTS - FTSE
 Fuel temperature sensor
 2.0 - 3.0 kΩ (at 20 °C)
63 - 87
 WTS - WTSE
 Engine coolant temperature sensor
 14 - 17 kΩ (at -20°C)
[5.1 - 6.5 kΩ (at 0°C)]
2.1 - 2.7 kΩ (at 20°C)
[0.9 - 1.3 kΩ (at 40°C)]
[0.48 - 0.68 kΩ (at 60°C)]
[0.26 - 0.36 kΩ (at 80°C)]
116 - Body earth
 GNDB - Body earth
 Engine-ECU earth
 Continuity (2 Ω or less)
117 - Body earth
 GNDE - Body earth
145 - Body earth
 SGND - Body earth
114 - 129
 ETV+ - ETV-
 Throttle valve control servo
 0.3 - 100 Ω (at 20 °C)
131 - 146
 SCV+ - SCV-
 Suction control valve
 Approximately 2.1 Ω (at 20°C)