Suzuki GSX-R 1000 Service Manual: DTC “c29” (p1654-h/l): secondary throttle position sensor (stps) circuit malfunction

Detected condition

Possible cause

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.
• Stp sensor circuit shorted to vcc or ground circuit open.
• Stp sensor circuit open or shorted to ground or vcc circuit open.

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.

after repairing the trouble, clear the dtc using sds tool. Refer to “use of sds diagnosis reset procedures” .

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 .
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?

• Loose or poor contacts on the ecm coupler.
• Open or short circuit in the r wire or b/br wire.

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 .
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 .
7. Check the continuity between the y/w wire and terminal “18”. 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?

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 .
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 ground.

   Also, check the continuity between the y/w 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 couplers. Refer to “ecm removal and installation” in section 1c .
7. Check the continuity between the y/w wire and terminal “18”. Also, check the continuity between the r wire and terminal “7”.

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?

2

1. Connect the ecm couplers.
2.  Turn the ignition switch on.
3.  Measure the input voltage between the r wire and ground. Also, measure the input 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?

3

1. Turn the ignition switch off.
2.  Connect the ecm couplers and stp sensor couplers.
3.  Remove the air cleaner box cover. Refer to “air cleaner element removal and installation” in section 1d .
4.  Disconnect the stva lead wire coupler (1).

5. Insert the needle point probes to the lead wire coupler.
6.  Turn the ignition switch on.
7.  Measure the stp sensor output voltage at the coupler (between the y/w wire (+) and b/br wire (–)) by turning the secondary throttle valve (close and open) with your finger.

Special tool
(a): 09900–25008 (multi
circuit tester set)
(b): 09900–25009
(needle-point probe set)

Tester knob indication voltage ( )

Stp sensor output voltage secondary throttle valve is closed: approx. 0.7 V secondary throttle valve is opened: approx. 4.1 V ((+) terminal: y/w – (–) terminal: b/br)

Is the voltage ok?

• R, y/w or b/br wire open or shorted to ground, or poor “7”, “18” 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 .