Suzuki GSX-R1000. Service Manual - part 8

1A-50 Engine General Information and Diagnosis: 

DTC “C15” (P0115-H/L): ECT Sensor Circuit Malfunction

B947H11104014

Detected Condition and Possible Cause

Wiring Diagram

ECM coupler (Harness side)

Troubleshooting

CAUTION

!

 

When using the multi-circuit tester, do not strongly touch the terminal of the ECM coupler with a 
needle pointed tester probe to prevent terminal damage.

 

NOTE

After repairing the trouble, clear the DTC using SDS tool. Refer to “Use of SDS Diagnosis Reset 
Procedures” (Page 1A-14).

 

Detected Condition

Possible Cause

C15

Output voltage is not with in the following 
range.
0.15 V 

≤

 Sensor voltage < 4.85 V

• ECT sensor circuit open or short.

• ECT sensor malfunction.

• ECM malfunction.

P0115

H

Sensor voltage is higher than specified 
value.

• ECT sensor circuit is open or ground circuit open.

L

Sensor voltage is lower than specified 
value.

• ECT sensor circuit shorted to ground.

ECM

E2

ECTS

B/Br

ECT sensor

B/BI

32

35

I837H1110027-01

1

2

3

4

5

6

7

8

9 10 11 12

13 14 15 16 17 18 19 20 21 22 23 24

25 26 27 28 29 30 31 32 33 34 35 36

37 38 39 40 41 42 43 44 45 46 47 48

49 50 51 52 53 54 55 56 57 58 59 60

61 62 63 64 65 66 67 68 69 70 71 72

I837H1110007-02

Engine General Information and Diagnosis:  1A-51

C15 (Use of mode select switch)

Step

Action

Yes

No

1

1) Turn the ignition switch OFF.

2) Remove the left side cowling. Refer to “Exterior Parts 

Removal and Installation” in Section 9D (Page 9D-6).

3) Check the ECT sensor coupler (1) for loose or poor 

contacts.
If OK, then measure the ECT sensor input voltage. 

4) Disconnect the ECT coupler and turn the ignition switch 

ON.

5) Measure the input voltage between the B/Bl wire and 

ground.
If OK, then measure the input voltage between the B/Bl 
wire and B/Br wire.

Special tool

(A):  09900–25008 (Multi circuit tester set)

Tester knob indication
Voltage (

)

ECT sensor input voltage
4.5 – 5.5 V
((+) terminal: B/Bl – (–) terminal: Ground, (+) 
terminal: B/Bl – (–) terminal: B/Br)

Is the voltage OK?

Go to Step 2.

• Loose or poor 

contacts on the ECM 
coupler.

• Open or short circuit 

in the B/Bl or B/Br 
wire.

1

I947H1110114-01

(A)

I718H1110048-03

1A-52 Engine General Information and Diagnosis: 

P0115-H (Use of SDS)

Step

Action

Yes

No

1

1) Turn the ignition switch OFF.

2) Remove the left side cowling. Refer to “Exterior Parts 

Removal and Installation” in Section 9D (Page 9D-6).

3) Check the ECT sensor coupler (1) for loose or poor 

contacts.
If OK, then check the ECT sensor lead wire continuity.

4) Disconnect the ECT sensor coupler.

5) Disconnect the ECM coupler. Refer to “ECM Removal 

and Installation” in Section 1C (Page 1C-1).

6) Insert the needle pointed probes to the lead wire coupler.

7) Check the continuity between the B/Bl wire and terminal 

“32”. Also, check the continuity between the B/Br wire 
and terminal “35”.

Special tool

(A):  09900–25008 (Multi circuit tester set)
(B):  09900–25009 (Needle-point probe set)

Tester knob indication
Continuity test (

)

ECM couplers (Harness side)

Is the continuity OK?

Go to Step 2.

B/Bl or B/Br wire open.

1

I947H1110115-01

(Black)

(Gray)

?

(A)

“32”

“35”

(B)

I837H1110030-01

Engine General Information and Diagnosis:  1A-53

P0115-L (Use of SDS)

Step

Action

Yes

No

1

1) Turn the ignition switch OFF.

2) Remove the left side cowling. Refer to “Exterior Parts 

Removal and Installation” in Section 9D (Page 9D-6).

3) Check the ECT sensor coupler (1) for loose or poor 

contacts.
If OK, then check the ECT sensor lead wire continuity.

4) Disconnect the ECT sensor coupler.

5) Check the continuity between the B/Bl wire and ground. 

If the sound is not heard from the tester, the circuit 
condition is OK.

Special tool

(A):  09900–25008 (Multi circuit tester set)

Tester knob indication
Continuity test (

)

6) Connect the ECT sensor coupler.

7) Insert the needle pointed probes to the lead wire coupler.

8) Turn the ignition switch ON.

Go to Step 2.

• B/Bl wire shorted to 

ground.

• If wire is OK, go to 

Step 2.

1

I947H1110116-01

(A)

I718H1110054-03

1A-54 Engine General Information and Diagnosis: 

Step

Action

Yes

No

1

9) Measure the output voltage between the B/Bl wire and 

ground.

Special tool

(A):  09900–25008 (Multi circuit tester set)
(B):  09900–25009 (Needle-point probe set)

Tester knob indication
Voltage (

)

ECT sensor output voltage
0.15 – 4.85 V
((+) terminal: B/Bl – (–) terminal: Ground)

Are the continuity and voltage OK?

Go to Step 2.

• B/Bl wire shorted to 

ground.

• If wire is OK, go to 

Step 2.

2

1) Turn the ignition switch OFF.

2) Disconnect the ECT sensor coupler.

3) Measure the ECT sensor resistance.

Special tool

(A):  09900–25008 (Multi circuit tester set)

Tester knob indication
Resistance (

Ω

)

ECT sensor resistance
Approx. 2.45 k

Ω

 at 20 

°

C (68 

°

F)

(Terminal – Terminal)

NOTE

Refer to “ECT Sensor Inspection” in Section 1C 
(Page 1C-4) for details.

 

Is the resistance OK?

• B/Bl or B/Br wire 

open or shorted to 
ground, or poor “32” 
or “35” connection.

• If wire and 

connection are OK, 
intermittent trouble or 
faulty ECM.

• Recheck each 

terminal and wire 
harness for open 
circuit and poor 
connection.

• Replace the ECM 

with a known good 
one, and inspect it 
again. Refer to “ECM 
Removal and 
Installation” in 
Section 1C 
(Page 1C-1).

Replace the ECT 
sensor with a new one. 
Refer to “ECT Sensor 
Removal and 
Installation” in Section 
1C (Page 1C-4).

V

(B)

(A)

I947H1110024-01

(A)

I947H1110025-01

Engine General Information and Diagnosis:  1A-55

DTC “C21” (P0110-H/L): IAT Sensor Circuit Malfunction

B947H11104015

Detected Condition and Possible Cause

Wiring Diagram

ECM coupler (Harness side)

Troubleshooting

CAUTION

!

 

When using the multi-circuit tester, do not strongly touch the terminal of the ECM coupler with a 
needle pointed tester probe to prevent terminal damage.

 

NOTE

After repairing the trouble, clear the DTC using SDS tool. Refer to “Use of SDS Diagnosis Reset 
Procedures” (Page 1A-14).

 

Detected Condition

Possible Cause

C21

Output voltage is not with in the following 
range.
0.15 V 

≤

 Sensor voltage < 4.85 V

• IAT sensor circuit open or short.

• IAT sensor malfunction.

• ECM malfunction.

P0110

H

Sensor voltage is higher than specified 
value.

• IAT sensor circuit open or ground circuit open.

L

Sensor voltage is lower than specified 
value.

• IAT sensor circuit shorted to ground.

ECM

B/Br

E2

IATS

Dg

B/Br

Dg

IAT sensor

33

35

I947H1110124-01

1

2

3

4

5

6

7

8

9 10 11 12

13 14 15 16 17 18 19 20 21 22 23 24

25 26 27 28 29 30 31 32 33 34 35 36

37 38 39 40 41 42 43 44 45 46 47 48

49 50 51 52 53 54 55 56 57 58 59 60

61 62 63 64 65 66 67 68 69 70 71 72

I837H1110007-02

1A-56 Engine General Information and Diagnosis: 

C21 (Use of mode select switch)

Step

Action

Yes

No

1

1) Turn the ignition switch OFF.

2) Lift and support the fuel tank. Refer to “Fuel Tank 

Removal and Installation” in Section 1G (Page 1G-9).

3) Move the air cleaner box upward. Refer to “Air Cleaner 

Box Removal and Installation” in Section 1D (Page 1D-
7).

4) Check the IAT sensor coupler (1) for loose or poor 

contacts.
If OK, then measure the IAT sensor input voltage.

5) Disconnect the IAT sensor coupler and turn the ignition 

switch ON.

6) Measure the input voltage between the Dg wire terminal 

and ground.
If OK, then measure the input voltage between the Dg 
wire terminal and B/Br wire terminal.

Special tool

(A):  09900–25008 (Multi circuit tester set)

Tester knob indication
Voltage (

)

IAT sensor input voltage
4.5 – 5.5 V
((+) terminal: Dg – (–) terminal: Ground, (+) terminal: 
Dg – (–) terminal: B/Br)

Is the voltage OK?

Go to Step 2.

• Loose or poor 

contacts on the ECM 
coupler.

• Open or short circuit 

in the Dg or B/Br 
wire.

1

I947H1110026-01

V

(A)

I823H1110040-03

Engine General Information and Diagnosis:  1A-57

P0110-H (Use of SDS)

Step

Action

Yes

No

1

1) Turn the ignition switch OFF.

2) Lift and support the fuel tank. Refer to “Fuel Tank 

Removal and Installation” in Section 1G (Page 1G-9).

3) Move the air cleaner box upward. Refer to “Air Cleaner 

Box Removal and Installation” in Section 1D (Page 1D-
7).

4) Check the IAT sensor coupler (1) for loose or poor 

contacts.
If OK, then check the IAT sensor lead wire continuity.

5) Disconnect the IAT sensor coupler.

6) Disconnect the ECM coupler. Refer to “ECM Removal 

and Installation” in Section 1C (Page 1C-1).

7) Insert the needle pointed probes to the lead wire coupler.

8) Check the continuity between the Dg wire and terminal 

“33”. Also, check the continuity between the B/Br wire 
and terminal “35”.

Special tool

(A):  09900–25008 (Multi circuit tester set)
(B):  09900–25009 (Needle-point probe set)

Tester knob indication
Continuity test (

)

ECM couplers (Harness side)

Is the continuity OK?

Connect the ECM 
coupler and go to Step 
2.

Dg or B/Br wire open.

1

I947H1110027-01

(Black)

(Gray)

?

(A)

“33”

“35”

(B)

I837H1110037-01

1A-58 Engine General Information and Diagnosis: 

P0110-L (Use of SDS)

Step

Action

Yes

No

1

1) Turn the ignition switch OFF.

2) Lift and support the fuel tank. Refer to “Fuel Tank 

Removal and Installation” in Section 1G (Page 1G-9).

3) Move the air cleaner box upward. Refer to “Air Cleaner 

Box Removal and Installation” in Section 1D (Page 1D-
7).

4) Check the IAT sensor coupler (1) for loose or poor 

contacts.
If OK, then check the IAT sensor lead wire continuity.

5) Disconnect the IAT sensor coupler.

6) Check the continuity between the Dg wire and ground. If 

the sound is not heard from the tester, the circuit 
condition is OK.

Special tool

(A):  09900–25008 (Multi circuit tester set)

Tester knob indication
Continuity test (

)

7) Connect the IAT sensor coupler.

8) Turn the ignition switch ON.

9) Insert the needle pointed probes to the lead wire coupler.

Go to Step 2.

• Dg wire shorted to 

ground.

• If wire is OK, go to 

Step 2.

1

I947H1110028-01

(A)

I823H1110042-03

Engine General Information and Diagnosis:  1A-59

Step

Action

Yes

No

1

10) Measure the output voltage between the Dg wire and 

ground.

Special tool

(A):  09900–25008 (Multi circuit tester set)
(B):  09900–25009 (Needle-point probe set)

Tester knob indication
Voltage (

)

IAT sensor output voltage
0.15 – 4.85 V
((+) terminal: Dg – (–) terminal: Ground)

Are the continuity and voltage OK?

Go to Step 2.

• Dg wire shorted to 

ground.

• If wire is OK, go to 

Step 2.

2

1) Turn the ignition switch OFF.

2) Remove the air cleaner box. Refer to “Air Cleaner Box 

Removal and Installation” in Section 1D (Page 1D-7).

3) Measure the IAT sensor resistance.

Special tool

(A):  09900–25008 (Multi circuit tester set)

Tester knob indication
Resistance (

Ω

)

IAT sensor resistance
Approx. 2.58 k

Ω

 at 20 

°

C (68 

°

F)

(Terminal – Terminal)

NOTE

IAT sensor resistance measurement method is 
the same way as that of the ECT sensor. Refer to 
“ECT Sensor Inspection” in Section 1C 
(Page 1C-4).

 

Is the resistance OK?

• Dg or B/Br wire open 

or shorted to ground, 
or poor “33” or “35” 
connection.

• If wire and 

connection are OK, 
intermittent trouble or 
faulty ECM.

• Recheck each 

terminal and wire 
harness for open 
circuit and poor 
connection.

• Replace the ECM 

with a known good 
one, and inspect it 
again. Refer to “ECM 
Removal and 
Installation” in 
Section 1C 
(Page 1C-1).

Replace the IAT sensor 
with a new one. Refer to 
“IAT Sensor Removal 
and Installation” in 
Section 1C (Page 1C-
5).

V

(A)

(B)

I947H1110029-01

(A)

I815H1110031-01

1A-60 Engine General Information and Diagnosis: 

DTC “C22” (P1450-H/L): AP Sensor Circuit Malfunction

B947H11104016

Detected Condition and Possible Cause

Wiring Diagram

ECM coupler (Harness side)

Troubleshooting

CAUTION

!

 

When using the multi-circuit tester, do not strongly touch the terminal of the ECM coupler with a 
needle pointed tester probe to prevent terminal damage.

 

NOTE

After repairing the trouble, clear the DTC using SDS tool. Refer to “Use of SDS Diagnosis Reset 
Procedures” (Page 1A-14).

 

Detected Condition

Possible Cause

C22

AP sensor voltage is not within the 
following range.
0.5 V 

≤

 Sensor voltage < 4.85 V

NOTE

Note that atmospheric pressure 
varies depending on weather 
conditions as well as altitude.
Take that into consideration 
when inspecting voltage.

 

• Clogged vacuum passage with dust.

• AP sensor circuit open or shorted to ground.

• AP sensor malfunction.

• ECM malfunction.

P1450

H

Sensor voltage is higher than specified 
value.

• AP sensor circuit is open or shorted to VCC or ground 

circuit open.

L

Sensor voltage is lower than specified 
value.

• AP sensor circuit is shorted to ground or VCC circuit 

open.

ECM

R

APS

E2

VCC

AP sensor

G/Y

B/Br

35

20

7

I837H1110040-01

1

2

3

4

5

6

7

8

9 10 11 12

13 14 15 16 17 18 19 20 21 22 23 24

25 26 27 28 29 30 31 32 33 34 35 36

37 38 39 40 41 42 43 44 45 46 47 48

49 50 51 52 53 54 55 56 57 58 59 60

61 62 63 64 65 66 67 68 69 70 71 72

I837H1110007-02

Engine General Information and Diagnosis:  1A-61

C22 (Use of mode select switch)

Step

Action

Yes

No

1

1) Turn the ignition switch OFF.

2) Remove the front seat. Refer to “Exterior Parts Removal 

and Installation” in Section 9D (Page 9D-6).

3) Remove the starter relay from the bracket.

4) Check the AP sensor coupler (1) for loose or poor 

contacts.
If OK, then measure the AP sensor input voltage.

5) Disconnect the AP sensor coupler.

6) Turn the ignition switch ON.

7) Measure the input voltage between the R wire and 

ground.
If OK, then measure the voltage between the R wire and 
B/Br wire.

Special tool

(A):  09900–25008 (Multi circuit tester set)

Tester knob indication
Voltage (

)

AP sensor input voltage
4.5 – 5.5 V
((+) terminal: R – (–) terminal: Ground, (+) terminal: R 
– (–) terminal: B/Br)

Is the voltage OK?

Go to Step 3.

• Loose or poor 

contacts on the ECM 
couplers.

• Open or short circuit 

in the R or B/Br wire.

1

I947H1110030-01

(A)

V

I823H1110016-05

1A-62 Engine General Information and Diagnosis: 

P1450-H (Use of SDS)

Step

Action

Yes

No

1

1) Turn the ignition switch OFF.

2) Remove the front seat. Refer to “Exterior Parts Removal 

and Installation” in Section 9D (Page 9D-6).

3) Remove the starter relay from the bracket.

4) Check the AP sensor coupler (1) for loose or poor 

contacts.
If OK, then check the AP sensor lead wire continuity.

5) Disconnect the AP sensor coupler.

6) Check the continuity between the R wire and G/Y wire.

If the sound is not heard from the tester, the circuit 
condition is OK.

Special tool

(A):  09900–25008 (Multi circuit tester set)

Tester knob indication
Continuity (

)

7) Disconnect the ECM couplers. Refer to “ECM Removal 

and Installation” in Section 1C (Page 1C-1).

8) Insert the needle pointed probes to the lead wire coupler.

Go to Step 3.

G/Y wire shorted to 
VCC, or B/Br wire open.

1

I947H1110031-01

(A)

I823H1110017-05

Engine General Information and Diagnosis:  1A-63

Step

Action

Yes

No

1

9) Check the continuity between the G/Y wire and terminal 

“20”.
If OK, then check the continuity between the B/Br wire 
and terminal “35”.

Special tool

(A):  09900–25008 (Multi circuit tester set)
(B):  09900–25009 (Needle-point probe set)

Tester knob indication
Continuity test (

)

ECM coupler (Harness side)

Is the continuity OK?

Go to Step 3.

G/Y wire shorted to 
VCC, or B/Br wire open.

(Black)

(Gray)

?

(A)

(B)

“20”

“35”

I837H1110043-01

1A-64 Engine General Information and Diagnosis: 

P1450-L (Use of SDS)

Step

Action

Yes

No

1

1) Turn the ignition switch OFF.

2) Remove the front seat. Refer to “Exterior Parts Removal 

and Installation” in Section 9D (Page 9D-6).

3) Remove the starter relay from the bracket.

4) Check the AP sensor coupler (1) for loose or poor 

contacts.
If OK, then check the AP sensor lead wire continuity.

5) Disconnect the AP sensor coupler.

6) Check the continuity between the G/Y wire and ground. 

Also, check the continuity between the G/Y wire and B/
Br wire. If the sound is not heard from the tester, the 
circuit condition is OK.

Special tool

(A):  09900–25008 (Multi circuit tester set)

Tester knob indication
Continuity (

)

7) Disconnect the ECM couplers. Refer to “ECM Removal 

and Installation” in Section 1C (Page 1C-1).

8) Insert the needle pointed probes to the lead wire coupler.

Go to Step 2.

R and G/Y wire open, G/
Y wire shorted to 
ground.

1

I947H1110032-01

(A)

I823H1110019-02

Engine General Information and Diagnosis:  1A-65

Step

Action

Yes

No

1

9) Check the continuity between the R wire and terminal 

“7”. Also, check the continuity between the G/Y wire and 
terminal “20”.

Special tool

(A):  09900–25008 (Multi circuit tester set)
(B):  09900–25009 (Needle-point probe set)

Tester knob indication
Continuity (

)

ECM coupler (Harness side)

Is the continuity OK?

Go to Step 2.

R and G/Y wire open, G/
Y wire shorted to 
ground.

2

1) Connect the ECM couplers.

2) Turn the ignition switch ON.

3) Measure the input voltage between the R wire and 

ground.
If OK, then measure the voltage between the R wire and 
B/Br wire.

Special tool

(A):  09900–25008 (Multi circuit tester set)

Tester knob indication
Voltage (

)

AP sensor input voltage
4.5 – 5.5 V
((+) terminal: R – (–) terminal: Ground, (+) terminal: R 
– (–) terminal: B/Br)

Is the voltage OK?

Go to Step 3.

• Loose or poor 

contacts on the ECM 
couplers.

• Open or short circuit 

in the R or B/Br wire.

(Black)

(Gray)

?

(A)

(B)

“7”

“20”

I837H1110045-02

(A)

V

I823H1110016-05