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Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis:  1A-175
Inspection of ECM and Its CircuitsS7RS0B1104079
ECM and its circuits can be checked by measuring voltage, pulse signal and resistance with special tool connected.
CAUTION! 
ECM cannot be checked by itself. It is strictly prohibited to connect voltmeter or ohmmeter to ECM 
with ECM connectors disconnected from it.
 
Voltage Check
1) Remove ECM (1) from its bracke t referring to “ECM Removal and Installation in Section 1C”.
2) Connect special tool between EC M and ECM connectors securely.
Special tool
(A):  09933–06320
3) Check voltage and/or pulse signal us ing voltmeter (2) and oscilloscope (3).
NOTE
• As each terminal voltage is affected by battery voltag e, confirm that it is 11 V or more when ignition 
switch is turned ON.
• Voltage with asterisk (*) cannot be measured with voltmeter because it is pulse signal. Use  oscilloscope for its check if necessary.
• Before this inspection, be sure to read the “Precautions of ECM Circuit Inspection”.
 
Viewed from harness side
1
2
3 (A)
I5RS0C110023-01
E23
C37
34
1819
567
1011
17
20
47 46
495051
2122
52 16
25 9
24
14
29
55
57 54 53
59
60 58 2
262728
15
30
56 4832 31
34353637
40
42 39 38
44
45 43 41 331
1213
238
34
1819
567
1011
17
20
47 46
495051
2122
52 16
25 9
24
14
29
55
57 54 53
59
60 58 2
262728
15
30
56 4832 31
34353637
40
42 39 38
44
45 43 41 331
1213
238
I4RS0A110055-01  
         
        
        
     
        
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Downloaded from www.Manualslib.com manuals search engine 1A-176 Engine General Information and Diagnosis: 
Terminal No. Wire 
color Circuit Normal voltage Condition Remarks
C37-1 BLU/
YEL Fuel injector No.1 
output 10 – 14 V Ignition switch turned ON. —
*0 – 0.6 V ↑↓
10 – 14 V
(“Reference 
waveform No.1: ”, 
“Reference waveform  No.2: ” and 
“Reference waveform  No.22: ”) Engine running at idle 
after warmed up engine.
Output signal is active low 
pulse. Pulse frequency 
varies depending on 
engine speed.
C37-2 BLU/
WHT Fuel injector No.2 
output 10 – 14 V Ignition switch turned ON. —
*0 – 0.6 V ↑↓
10 – 14 V
(“Reference 
waveform No.1: ” and 
“Reference waveform  No.3: ”) Engine running at idle 
after warmed up engine.
Output signal is active low 
pulse. Pulse frequency 
varies depending on 
engine speed.
C37-3 GRN/
ORN EGR valve 
(stepper motor coil 
2) output 10 – 14 V Ignition switch turned ON. —
*0 – 1 V ↑↓
10 – 14 V
(“Reference 
waveform No.4: ”) Ignition switch is turned to 
ST (cranking) position. Output signal is active low 
duty pulse. Number of 
pulse generated times 
varies depending on 
vehicle condition.
C37-4 GRN/
RED EGR valve 
(stepper motor coil 
1) output 10 – 14 V Ignition switch turned ON. —
*0 – 1 V
↑↓
10 – 14 V
(“Reference 
waveform No.4: ”) Ignition switch is turned to 
ST (cranking) position. Output signal is active low 
duty pulse. Number of 
pulse generated times 
varies depending on 
vehicle condition.
C37-5 GRN/
WHT Ignition coil No.2 
and No.3 output 0 – 0.6 V Ignition switch turned ON. —
*0 – 0.6 V ↑↓
3 – 5 V
(“Reference 
waveform No.5: ” and 
“Reference waveform  No.6: ”) Engine running at idle 
after warmed up engine.
Output signal is active 
high pulse. Pulse 
frequency varies 
depending on engine 
speed.
C37-6 GRN/
YEL Ignition coil No.1 
and No.4 output 0 – 0.6 V Ignition switch turned ON. —
*0 – 0.6 V ↑↓
3 – 5 V
(“Reference 
waveform No.6: ”, 
“Reference waveform  No.7: ” and 
“Reference waveform  No.22: ”
 )Engine running at idle 
after warmed up engine.
Output signal is active 
high pulse. Pulse 
frequency varies 
depending on engine 
speed.
C37-7 — —— — —
C37-8 BRN/
WHT Generator field coil 
monitor signal 10 – 14 V Ignition switch turned ON.
Signal is duty pulse. Duty 
ratio varies depending on 
vehicle condition.
*0 – 1 V
↑↓
10 – 14 V
(“Reference 
waveform No.8: ”) Engine running at idle 
after warmed up engine.
C37-9 — —— — —  
         
        
        
     
        
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Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis:  1A-177
C37-10 WHTOxygen signal of 
HO2S-1 0 – 1 V Ignition switch turned ON.
—
*Deflects between 
over 0.5 V and under  0.45 V
(“Reference 
waveform No.10: ”  and “Reference 
waveform No.11: ”) While engine running at 
2,000 r/min. for 1 min. or 
longer after warmed up.
C37-11 BRN Oxygen signal of 
HO2S-2 4 – 5 V Ignition switch turned ON.
—
*Deflects between 
over 0.5 V and under  0.45 V
(“Reference 
waveform No.12: ”) While engine running at 
2,000 r/min. or more after 
vehicle running over 30 
km/h, 19 mph for 5 min.
C37-12 WHT CAN (low) 
(communication 
line (active low 
signal) to TCM (A/T 
model) *0.5 – 2.5 V
(“Reference 
waveform No.13: ”) Ignition switch turned ON 
with engine stop. CAN communication line 
signal is pulse. Pulse 
signal displayed with a 
regular frequency which 
varies depending on 
engine condition.
C37-13 RED CAN (high) 
communication line 
(active high signal) 
to TCM (A/T 
model) *2.5 – 4.5 V
(“Reference 
waveform No.13: ”)
C37-14 GRY/
RED Output of 5 V 
power source for 
MAP sensor, A/C 
refrigerant 
pressure sensor
4.5 – 5.5 V Ignition switch turned ON. —
C37-15 BLK Ground for ECM Below 0.3 V Ignition switch turned ON. —
C37-16 BLU/
RED Fuel injector No.3 
output 10 – 14 V Ignition switch turned ON. —
*0 – 0.6 V ↑↓
10 – 14 V
(“Reference 
waveform No.1: ” and 
“Reference waveform  No.14: ”) Engine running at idle 
after warmed up engine.
Output signal is active low 
pulse. Pulse frequency 
varies depending on 
engine speed.
C37-17 BLU/
ORNFuel injector No.4 
output 10 – 14 V Ignition switch turned ON. —
*0 – 0.6 V ↑↓
10 – 14 V
(“Reference 
waveform No.1: ” and 
“Reference waveform  No.15: ”) Engine running at idle 
after warmed up engine.
Output signal is active low 
pulse. Pulse frequency 
varies depending on 
engine speed.
C37-18 BRN/
YEL EGR valve 
(stepper motor coil 
4) output 10 – 14 V Ignition switch turned ON. —
*0 – 1 V ↑↓
10 – 14 V
(“Reference 
waveform No.4: ”) Ignition switch is turned to 
ST (cranking) position. Output signal is active low 
duty pulse. Number of 
pulse generated times 
varies depending on 
vehicle condition.
C37-19 WHT/
RED EGR valve 
(stepper motor coil 
3) output 10 – 14 V Ignition switch turned ON. —
*0 – 1 V ↑↓
1
0 – 14 V
(“Reference 
waveform No.4: ”) Ignition switch is turned to 
ST (cranking) position. Output signal is active low 
duty pulse. Number of 
pulse generated times 
varies depending on 
vehicle condition.
Terminal 
No. Wire 
color Circuit Normal voltage
ConditionRemarks  
         
        
        
     
        
        Page 228 of 1496

Downloaded from www.Manualslib.com manuals search engine 1A-178 Engine General Information and Diagnosis: 
C37-20RED/
YEL CMP sensor signal 0 – 1 V or 4 – 5 V Ignition switch turned ON. —
*0 – 0.6 V↑↓
4 – 5 V
(“Reference 
waveform No.16: ”  and “Reference 
waveform No.17: ”) Engine running at idle 
after warmed up engine.
Sensor signal is pulse. 
Pulse frequency varies 
depending on engine 
speed.
(6 pulses are generated 
per 1 camshaft revolution.)
C37-21 PNK CKP sensor signal 0 – 1 V or 4 – 5 V Ignition switch turned ON. —
*4 – 5 V↑↓
0 – 0.6 V
(“Reference 
waveform No.16: ”  and “Reference 
waveform No.17: ”) Engine running at idle 
after warmed up engine. Sensor signal is pulse. 
Pulse frequency varies 
depending on engine 
speed.
(30 (36 – 6) pulses are 
generated per 1 
crankshaft revolution.)
C37-22 — — — — —
C37-23 PNK/
BLU Electric load 
current sensor 
signal 3.8 – 4.2 V Ignition switch turned ON.
—
3.0 – 3.4 V
Ignition switch turned ON 
and headlight switch 
turned ON (HI beam).
2.3 – 2.7 V Ignition switch turned ON, 
headlight switch turned 
ON (HI beam) and blower 
selector at HI position.
C37-24 LT GRN ECT sensor signal 3.3 – 3.8 V
Ignition switch turned ON, 
ECT at 0 
°C, 32  °F.
—
1.38 – 1.72 V Ignition switch turned ON, 
ECT at 50 
°C, 122  °F.
0.40 – 0.53 V Ignition switch turned ON, 
ECT at 100 
°C, 212  °F.
C37-25 BLK/
YEL IAT sensor signal 3.18 – 3.67 V
Ignition switch turned ON, 
IAT at 0 
°C, 32  °F.
—
1.32 – 1.65 V Ignition switch turned ON, 
IAT at 40 
°C, 104  °F.
0.46 – 0.60 V Ignition switch turned ON, 
IAT at 80 
°C, 176  °F.
C37-26 GRN/
BLK MAF sensor signal 0.5 – 1.5 V
Ignition switch turned ON 
with engine at stop.
—
1.5 – 2.0 V
(“Reference 
waveform No.18: ”) Wh
en engine running at 
specified idle speed after 
warmed up.
C37-27 GRY Ground for MAF 
sensor Below 0.3 V Ignition switch turned ON.
—
C37-28 BLU/
YEL Generator control 
signal output *0 – 0.6 V
↑↓
5 – 8 V
(“Reference 
waveform No.19: ”) Engine running at idle 
speed, headlight switch 
turned ON.
Output signal is active low 
duty pulse. Duty ratio 
varies depending on 
vehicle condition.
C37-29 BLU/
BLK EVAP canister 
purge valve output 10 – 14 V
Ignition switch turned ON 
with engine at stop. —
*0 – 0.6 V ↑↓
10 – 14 V
(“Reference 
waveform No.20: ”) Set EVAP canister purge 
valve at 52% by using 
“Misc Test” of scan tool.
Output signal is active low 
duty pulse. Duty ratio 
varies depending on 
vehicle condition.
C37-30 BLK Ground for ECM Below 0.3 V Ignition switch turned ON. —
C37-31 — —— — —
Terminal 
No. Wire 
color Circuit Normal voltage
ConditionRemarks  
         
        
        
     
        
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Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis:  1A-179
C37-32 ——— — —
C37-33 — —— — —
C37-34 — —— — —
C37-35 — —— — —
C37-36 — —— — —
C37-37 — —— — —
C37-38 — —— — —
C37-39 — —— — —
C37-40 WHT TP sensor (sub) 
signal 1.57 – 1.09 V
Ignition switch turned ON 
and accelerator pedal at 
idle position after warmed 
up engine.
—
3.88 – 4.45 V Ignition switch turned ON 
and accelerator pedal at 
full depressed position 
after warmed up engine.
C37-41 — Ground for shield 
wire of TP sensor 
circuit Below 0.3 V Ignition switch turned ON.
—
C37-42 BLK Ground for TP 
sensor Below 0.3 V Ignition switch turned ON.
—
C37-43 RED Output for 5 V 
power source of TP 
sensor 4.5 – 5.5 V Ignition switch turned ON.
—
C37-44 LT  
GRN/ BLK Output of throttle 
actuator 0 – 1 V
Ignition switch turned ON 
and accelerator pedal at 
idle position after warmed 
up engine.
Output signal is pulse. 
Duty ratio varies 
depending on throttle 
valve and accelerator  pedal position.
*0 – 1 V
↑↓
10 – 14 V
(“Reference 
waveform No.21: ”) Ignition switch turned ON 
and accelerator pedal at 
full depressed position 
after warmed up engine.
C37-45 LT  
GRN/ RED Output of throttle 
actuator 0 – 1 V
Ignition switch turned ON 
and accelerator pedal at 
full depressed position 
after warmed up engine.
Output signal is pulse. 
Duty ratio varies 
depending on throttle 
valve and accelerator  pedal position.
*0 – 1 V
↑↓
10 – 14 V
(“Reference 
waveform No.21: ”) Ignition switch turned ON 
and accelerator pedal at 
idle position after warmed 
up engine.
C37-46 BLK/
RED Heater output of 
HO2S-1 10 – 14 V Ignition switch turned ON.
—
*0 – 2 V ↑↓
10 – 14 V
(“Reference 
waveform No.10: ”  and “Reference 
waveform No.11: ”) Engine running at idle 
after warmed up engine.
Output signal is active low 
duty pulse. Duty ratio 
varies depending on 
engine condition.
C37-47 RED/
BLU Heater output of 
HO2S-2 10 – 14 V Ignition switch turned ON.
—
0 – 1 V
(“Reference 
waveform No.12: ”) Engine running at idle 
after vehicle running over 
30 km/h, 19 mph for 5 min.
C37-48 YEL/
GRN Starting motor 
signal 0 – 1 V Ignition switch turned ON.
—
6 – 14 V While engine cranking.
C37-
49 — —— — —
Terminal 
No. Wire 
color Circuit Normal voltage
ConditionRemarks  
         
        
        
     
        
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Downloaded from www.Manualslib.com manuals search engine 1A-180 Engine General Information and Diagnosis: 
C37-50 —Ground of ECM for 
shield wire Below 0.3 V Ignition switch turned ON. —
C37-51 — Ground of ECM for 
shield wire Below 0.3 V Ignition switch turned ON. —
C37-52 — Ground of ECM for 
shield wire Below 0.3 V Ignition switch turned ON. —
C37-53 RED/
BLK MAP sensor signal Approx. 4 V
(“Reference 
waveform No.23: ”) Ignition switch turned ON 
with barometric pressure 
at 100 kPa, 760 mmHg.
—
0.4 – 2.0 V
(“Reference 
waveform No.24: ”) While engine running at 
specified idle speed after 
warmed up with 
barometric pressure at 
100 kPa, 760 mmHg.
C37-54 GRN TP sensor (main) 
signal 0.75 – 1.08 V
Ignition switch turned ON 
and accelerator pedal at 
idle position after warmed 
up engine.
—
3.67 – 4.24 V Ignition switch turned ON 
and accelerator pedal at 
full depressed position 
after warmed up engine.
C37-55 ORN Ground for sensors Below 0.3 V Ignition switch turned ON. —
C37-56 RED Knock sensor 
signal 2 – 3 V
(“Reference 
waveform No.25: ”  and “Reference 
waveform No.26: ”) Ignition switch turned ON.
—
Engine running at 4000 r/
min. after warmed up.
C37-57 YEL Ground for sensors Below 0.3 V Ignition switch turned ON. —
C37-58 BLK/
ORN Ground for ECM Below 0.3 V Ignition switch turned ON.
—
C37-59 YEL/
GRN Oil control valve 
ground
Below 1.3 V Ignition switch turned ON.
—
C37-60 YEL/
RED Oil control valve 
output *0 – 0.6 V
↑↓
10 – 14 V
(“Reference 
waveform No.27: ”  and “Reference 
waveform No.28: ”) At the moment of ignition 
switch turned ON.
Output signal is active 
high pulse. Duty ratio 
varies depending on 
vehicle condition.
Terminal 
No. Wire 
color Circuit Normal voltage
ConditionRemarks
Terminal 
No. Wire 
color Circuit Normal voltage Condition Remarks
E23-1 BLK/
RED Main power supply 10 – 14 V Ignition switch turned ON. —
E23-2 WHT/
RED Power source for 
ECM internal 
memory
10 – 14 V Ignition switch turned ON. —
E23-3 RED CAN (high) 
communication line 
(active high signal) 
for ABS control 
module, BCM, 
combination meter *2.5 – 4.5 V
(“Reference 
waveform No.29: ”) Ignition switch turned ON 
with engine at stop. CAN communication line 
signal is pulse. Pulse 
signal displayed with a 
regular frequency with 
varies depending on 
engine condition.  
         
        
        
     
        
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Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis:  1A-181
E23-4 BRNEngine revolution 
signal output for P/
S control module 0 – 0.8 V
Ignition switch turned ON 
with engine at stop. —
*0 – 1 V ↑↓
8 – 14 V
(“Reference 
waveform No.30: ”  and “Reference 
waveform No.31: ”) While engine running. Output signal is pulse. 
Pulse frequency varies 
depending on engine 
speed.
(2 pulses are generated 
per 1 crankshaft 
revolution.)
(3000 r/min. = 100 Hz)
E23-5 PPL/
WHT Serial 
communication line 
of DLC 12 V
8 – 14 V Ignition switch turned ON. —
E23-6 — — — — —
E23-7 — — — — —
E23-8 — — — — —
E23-9 — — — — —
E23-10 — — — — — E23-11 — — — — —
E23-12 BLU Diagnosis switch 
terminal (Hong 
Kong model) 4 – 5 V Ignition switch turned ON. —
E23-13 YEL/
RED Clock signal for 
immobilizer coil 
antenna
10 – 14 V Ignition switch turned ON. —
E23-14 — — — — —
E23-15 GRN/
WHT Fuel pump relay 
output 0 – 2.5 V
For 2 sec. from the time 
ignition switch is turned 
ON or while engine is 
running.
—
10 – 14 V On and after 2 sec. from 
the time ignition switch is 
turned ON or while engine 
is at stop.
E23-16 BLK/
RED Main power supply 10 – 14 V Ignition switch turned ON. —
E23-17 — — — — —
E23-18 WHT CAN (low) 
communication line 
(active low signal) 
for ABS control 
module, BCM, 
combination meter *0.5 – 2.5 V
(“Reference 
waveform No.29: ”) Ignition switch turned ON 
with engine at stop. CAN communication line 
signal is pulse. Pulse 
signal displayed with a 
regular frequency which 
varies depending on 
engine condition.
E23-19 BLU/
WHT Electric load signal 
for heater blower 
motor 10 – 14 V
Ignition switch turned ON, 
blower fan selector at OFF 
position.
—
0 – 1 V Ignition switch turned ON, 
blower fan selector at 2nd 
speed position or more.
E23-20 GRN/
WHT Stop lamp switch 
signal 0 – 1 V
Ignition switch turned ON, 
stop lamp not lit up.
—
10 – 14 V Ignition switch turned ON, 
stop lamp lit up.
E23-21 — — — — —
E23-22 — — — — —
E23-23 — — — — —
E23-24 — — — — —
Terminal 
No. Wire 
color Circuit Normal voltage Condition Remarks  
         
        
        
     
        
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Downloaded from www.Manualslib.com manuals search engine 1A-182 Engine General Information and Diagnosis: 
E23-25 PPLVehicle speed 
signal output for P/
S control module *0 – 1 V
↑↓
10 – 14 V
(“Reference 
waveform No.32: ”) Vehicle running. Sensor signal is pulse. 
Pulse frequency varies 
depending on vehicle 
speed.
(21 pulses are generated 
per sec. at 30 km/h, 19 
mph.) (2561 pulses/km)
E23-26 RED/
BLU EPS signal 10 – 14 V Ignition switch turned ON.
—
0 – 1 V With engine running at idle 
speed, and steering wheel 
turned to the right or left as 
far as it stops.
E23-27 — — — — —
E23-28 YEL/
BLK Serial 
communication line 
for immobilizer coil 
antenna
10 – 14 V Ignition switch turned ON. —
E23-29 BLK/
WHT Ignition switch 
signal 0 – 1 V Ignition switch turned OFF.
—
10 – 14 V Ignition switch turned ON.
E23-30 WHT Starting motor 
control relay output 0 – 1 V Ignition switch turned ON.
—
0 – 1 V Ignition switch is turned to 
ST (engine cranking) 
position.
E23-31 BLK Ground for ECM Below 0.3 V Ignition switch turned ON. —
E23-32 RED/
YEL Power supply of 
throttle actuator 
drive circuit
10 – 14 V Ignition switch turned ON. —
E23-33 — — — — —
E23-34 RED Output for 5 V 
power source of 
APP sensor (sub) 4.5 – 5.5 V Ignition switch turned ON. —
E23-35 BRN Output for 5 V 
power source of 
APP sensor (main) 4.5 – 5.5 V Ignition switch turned ON. —
E23-36 YEL APP sensor (sub) 
signal 1.55 – 1.65 V
Ignition switch turned ON 
and accelerator pedal at 
idle position after warmed 
up engine.
—
4.18 – 5.12 V Ignition switch turned ON 
and accelerator pedal at 
full depressed position 
after warmed up engine.
E23-37 YEL APP sensor (main) 
signal 0.75 – 0.85 V
Ignition switch turned ON 
and accelerator pedal at 
idle position after warmed 
up engine.
—
3.46 – 4.24 V Ignition switch turned ON 
and accelerator pedal at 
full depressed position 
after warmed up engine.
E23-38 — — — — —
E23-39 — — — — —
E23-40 — — — — —
E23-41 — — — — —
E23-42 — — — — —
E23-43 — — — — —
E23-44 — — — — —
Terminal 
No. Wire 
color Circuit Normal voltage Condition Remarks