Suzuki GSX-R1000. Service Manual - part 9

1A-66 Engine General Information and Diagnosis: 

3

1) Turn the ignition switch OFF.

2) Connect the ECM couplers and AP sensor coupler.

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

4) Run the engine at idle speed and measure the AP 

sensor output voltage between the G/Y wire and B/Br 
wire.

Special tool

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

Tester knob indication
Voltage (

)

AP sensor output voltage
Approx. 3.6 V at 100 kPa (760 mmHg)
((+) terminal: G/Y – (–) terminal: B/Br)

Is the voltage OK?

Go to Step 4.

• Check the vacuum 

port for crack or 
damage.

• Open or short circuit 

in the G/Y wire.

• If vacuum hose and 

lead wire are OK, 
replace the AP 
sensor with a new 
one. Refer to “AP 
Sensor Removal and 
Installation” in 
Section 1C 
(Page 1C-5).

Step

Action

Yes

No

(A)

V

(B)

I947H1110033-02

Engine General Information and Diagnosis:  1A-67

4

1) Turn the ignition switch OFF.

2) Remove the AP sensor. Refer to “AP Sensor Removal 

and Installation” in Section 1C (Page 1C-5).

3) Connect the vacuum pump gauge to the vacuum port of 

the AP sensor.

4) Arrange 3 new 1.5 V batteries in series (1) (check that 

total voltage is 4.5 – 5.0 V) and connect (–) terminal to 
the ground terminal “B” and (+) terminal to the VCC 
terminal “A”.

5) Check the voltage between Vout terminal “C” and 

ground. Also, check if voltage reduces when vacuum is 
applied up to 53 kPa (400 mmHg) by using vacuum 
pump gauge.

Special tool

(A):  09917–47011 (Vacuum pump gauge set)
(B):  09900–25008 (Multi circuit tester set)

Tester knob indication
Voltage (

)

Is the voltage OK?

• G/Y, R or B/Br wire 

open or shorted to 
ground, or poor “7”, 
“20” 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).

If check result is not 
satisfactory, replace the 
AP sensor with a new 
one. Refer to “AP 
Sensor Removal and 
Installation” in Section 
1C (Page 1C-5).

Step

Action

Yes

No

1

(A)

“C”

“A”

“B”

(B)

I718H1110030-02

760 – 707

707 – 634

634 – 567

567 – 526

100 – 94

94 – 85

85 – 76

76 – 70

3.1 – 3.6

2.8 – 3.4

2.6 – 3.1

2.4 – 2.9

ALTITUDE (Reference)

ATOMOSPHERIC

PRESSURE

OUTPUT

VOLTAGE

mmHg

kPa

V

0 – 2 000

2 001 – 5 000

5 001 – 8 000

8 001 – 10 000

ft

0 – 610

611 – 1 524

1 525 – 2 438

2 439 – 3 048

m

I823H1110023-02

1A-68 Engine General Information and Diagnosis: 

DTC “C23” (P1651-H/L): TO Sensor Circuit Malfunction

B947H11104017

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

C23

The sensor voltage should be the 
following for 2 sec. and more, after ignition 
switch is turned ON.
0.2 V 

≤

 Sensor voltage < 4.8 V

• TO sensor circuit open or short.

• TO sensor malfunction.

• ECM malfunction.

P1651

H

Sensor voltage is higher than specified 
value.

• TO sensor circuit is open or ground circuit open.

L

Sensor voltage is lower than specified 
value.

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

circuit open.

B/Br

R

B

ECM

VCC

E2

TO sensor

TOS

7

31

35

I837H1110047-01

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-69

C23 (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 AP sensor from the bracket.

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

contacts.
If OK, then measure the TO sensor resistance.

5) Remove the TO sensor.

6) Measure the resistance between terminal “A” and 

terminal “C”.

Special tool

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

Tester knob indication
Resistance (

Ω

)

TO sensor resistance
16.5 – 22.3 k

Ω

(Terminal “A” – Terminal “C”)

Is the resistance OK?

Go to Step 2.

Replace the TO sensor 
with a new one. Refer to 
“TO Sensor Removal 
and Installation” in 
Section 1C (Page 1C-
6).

1

I947H1110034-01

(A)

“A”

“C”

I837H1110049-01

1A-70 Engine General Information and Diagnosis: 

P1651-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) Check the TO sensor coupler (1) for loose or poor 

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

4) Disconnect the TO sensor coupler.

5) Check the continuity between the R wire and B 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 test (

)

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.

Go to Step 2.

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

1

I947H1110035-01

(A)

I823H1110051-01

Engine General Information and Diagnosis:  1A-71

Step

Action

Yes

No

1

8) Check the continuity between the B wire and terminal 

“31”. Also, check the continuity between 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 2.

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

(Black)

(Gray)

?

(A)

(B)

“31”

“35”

I837H1110051-01

1A-72 Engine General Information and Diagnosis: 

P1651-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) Check the TO sensor coupler (1) for loose or poor 

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

4) Disconnect the TO sensor coupler.

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

Also, check the continuity between the B 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 test (

)

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.

Go to Step 2.

R or B wire open, or B 
wire shorted to ground.

1

I947H1110036-01

(A)

I823H1110053-02

Engine General Information and Diagnosis:  1A-73

Step

Action

Yes

No

1

8) Check the continuity between the R wire and terminal 

“7”. Also, then check the continuity between B wire and 
terminal “31”.

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 2.

R or B wire open, or B 
wire shorted to ground.

(Black)

(Gray)

?

(A)

(B)

“7”

“31”

I837H1110053-01

1A-74 Engine General Information and Diagnosis: 

2

1) Connect the ECM coupler and TO sensor coupler.

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

3) Turn the ignition switch ON.

4) Measure the voltage at the wire side coupler between B 

wire and B/Br wire.

Special tool

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

Tester knob indication
Voltage (

)

TO sensor voltage (Normal)
0.4 – 1.4 V
((+) terminal: B – (–) terminal: B/Br)

5) Dismount the TO sensor from its bracket and measure 

the voltage when it is leaned 65

°

 and more, left and right, 

from the horizontal level.

Special tool

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

TO sensor voltage (Leaning)
3.7 – 4.4 V
((+) terminal: B – (–) terminal: B/Br)

Is the voltage OK?

• R, B or B/Br wire 

open or shorted to 
ground, or poor “7”, 
“31” 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).

• Loosen or poor 

contacts on the ECM 
coupler.

• Open or short circuit.

• Replace the TO 

sensor with a new 
one. Refer to “TO 
Sensor Removal and 
Installation” in 
Section 1C 
(Page 1C-6).

Step

Action

Yes

No

(A)

(B)

I947H1110037-02

(A)

(B)

I947H1110038-01

Engine General Information and Diagnosis:  1A-75

DTC “C24” (P0351), “C25” (P0352), “C26” (P0353) or “C27” (P0354): Ignition System Malfunction

B947H11104018

NOTE

Refer to “No Spark or Poor Spark” in Section 1H (Page 1H-5) for details.

 

DTC “C28” (P1655): Secondary Throttle Valve Actuator (STVA) Malfunction

B947H11104019

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

The operation voltage does not reach the STVA.
ECM does not receive communication signal from the 
STVA. STVA can not operate properly or its motor locked.

• STVA malfunction.

• STVA circuit open or short.

• STVA motor malfunction.

ECM

STVA. 2B

STVA. 1A

STVA. 1B

STVA

B/Lg

P/W

G

W/B

STVA. 2A

3

4

27

28

W/B

B

P

G

I947H1110039-01

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-76 Engine General Information and Diagnosis: 

Step

Action

Yes

No

1

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

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

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

Element Removal and Installation” in Section 1D 
(Page 1D-6).

3) Check the STVA lead wire coupler (1) for loose or poor 

contacts.

4) Check whether the STVs open by turning the ignition 

switch ON.

Is the operation OK?

Go to Step 2.

• Loose or poor 

contacts on the STVA 
coupler.

• Open or short circuit 

in the B/Lg, P/W, G or 
W/B wire.

• If wire and 

connection are OK, 
go to Step 2.

1

I947H1110040-01

I947H1110127-01

Engine General Information and Diagnosis:  1A-77

2

1) Turn the ignition switch OFF.

2) Disconnect the STVA lead wire coupler.

3) Check the continuity between each terminal and ground.

Special tool

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

Tester knob indication
Resistance (

Ω

)

STVA continuity

∞

 

Ω

 (Infinity)

(Terminal – Ground)

4) If OK, then measure the STVA resistance (between the 

P wire “A” and B wire “B”) and (between the W/B wire 
“C” and G wire “D”).

Special tool

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

STVA resistance
Approx. 6.5 

Ω

(Terminal “A” – Terminal “B”, Terminal “C” – 
Terminal “D”)

Is the resistance OK?

• B/Lg, P/W, G and W/

B wire open or 
shorted to ground, or 
poor “3”, “4”, “27” and 
“28” 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).

• Loose or poor 

contacts on the ECM 
coupler.

• Replace the throttle 

body assembly with a 
new one. Refer to 
“Throttle Body 
Disassembly and 
Assembly” in Section 
1D (Page 1D-11).

Step

Action

Yes

No

(A)

I947H1110041-02

(A)

“A”

“C”

“B”

“D”

I947H1110042-02

1A-78 Engine General Information and Diagnosis: 

Active Control Inspection

1) Set up the SDS tool. (Refer to the SDS operation manual for further details.)

2) Turn the ignition switch ON.

3) Click “Secondary throttle operating control” (1).

4) Click each button (2).

At this time, if an operation sound is heard from the STVA, the function is normal.

1

I947H1110128-01

2

2

I947H1110129-01

Engine General Information and Diagnosis:  1A-79

DTC “C29” (P1654-H/L): Secondary Throttle Position Sensor (STPS) Circuit Malfunction

B947H11104020

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

C29

Output voltage is not within the following 
range.
Difference between actual throttle opening 
and opening calculated by ECM is larger 
than specified value.
0.15 V 

≤

 Sensor voltage < 4.85 V

• STP sensor maladjusted.

• STP sensor circuit open or short.

• STP sensor malfunction.

• ECM malfunction.

P1654

H

Sensor voltage is higher than specified 
value.

• STP sensor circuit shorted to VCC or ground circuit 

open.

L

Sensor voltage is lower than specified 
value.

• STP sensor circuit open or shorted to ground or VCC 

circuit open.

ECM

E2

VCC

R

Y/W

STPS

STP sensor

B/Br

Y/W

B/Br

R

7

18

35

I947H1110043-01

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-80 Engine General Information and Diagnosis: 

C29 (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) Check the STP sensor couplers (1) and (2) for loose or 

poor contacts.
If OK, then measure the STP sensor input voltage.

4) Disconnect the STP sensor coupler (1).

5) Turn the ignition switch ON.

6) Measure the input voltage between the R wire and 

ground. Also, measure the voltage between the R wire 
and B/Br wire.

Special tool

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

Tester knob indication
Voltage (

)

STP 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 
coupler.

• Open or short circuit 

in the R wire or B/Br 
wire.

1

2

I947H1110044-01

V

(A)

I947H1110045-01

Engine General Information and Diagnosis:  1A-81

P1654-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) Check the STP sensor couplers (1) and (2) for loose or 

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

4) Disconnect the STP sensor couplers (1) and (2).

5) Check the continuity between the Y/W wire and R 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 (

)

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

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

Go to Step 3.

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

1

2

I947H1110046-01

(A)

I947H1110047-02