Suzuki GSX-R 1000 Service Manual: DTC “c44” (p0130/p0135): ho2 sensor (ho2s) circuit malfunction

Detected condition

Possible cause

Sensor voltage > 1.0 V

• Ho2 sensor circuit is open or shorted to the power source.
• Heated circuit is open or shorted to ground.
•  Battery voltage is not supply to the ho2 sensor.

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 ho2 sensor coupler (1) for loose or poor contacts.

   If ok, then check the ho2 sensor lead wire continuity.

4. Disconnect the ho2 sensor coupler.
5.  Check the continuity between the w/g wire and o/w 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 .
7.  Check the continuity between the w/g wire and terminal “34”. 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 ( )

Ecm couplers (harness side)

Is the continuity ok?

2

1. Connect the ecm coupler and ho2 sensor coupler.
2.  Warm up the engine enough.
3.  Insert the needle pointed probes to the lead wire coupler.
4.  Measure the ho2 sensor output voltage between the w/ g (b) wire and b/br (gr) wire, in idling condition.

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

Tester knob indication voltage ( )

Ho2 sensor output voltage at idle speed 0.3 V and less ((+) terminal: w/g (b) – (–) terminal: b/br (gr))

5. If ok, then remove the air cleaner box and pinch the pair hose (1) with a proper hose clamp.

6. Measure the ho2 sensor output voltage while holding the engine speed at 5 000 r/min.

Ho2 sensor output voltage at 5 000 r/min 0.6 V and more ((+) terminal: w/g – (–) terminal: b/br)

Is the voltage ok?

• W/g or b/br wire open or shorted to the power source, or poor “34” 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 inspection it again. Refer to “ecm removal and installation” in section 1c .

Refer to “ho2 sensor removal and installation” in section 1c .

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 ho2 sensor coupler (1) for loose or poor contacts.

   If ok, then measure the ho2 sensor resistance.

4. Disconnect the ho2 sensor coupler and measure the resistance between terminals.

Special tool
(a): 09900–25008 (multi
circuit tester set)

Tester knob indication resistance (Ω)

Ho2 sensor heater resistance 6.7 – 9.5 Ω at 23 °c (73 °f) (w – w)

Is the resistance ok?

Refer to “ho2 sensor removal and installation” in section 1c .

2

1. Connect the ho2 sensor coupler.
2.  Insert the needle pointed probes to the lead wire coupler.
3.  Turn the ignition switch on and measure the heater voltage between the w/b wire and ground.

   If the tester voltage indicates the battery voltage, it is good condition.

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

Tester knob indication voltage ( )

Heater voltage battery voltage ((+) terminal: w/b – (–) terminal: ground)

Is the voltage ok?

• O/w or w/b wire open or shorted to ground, or poor “41” connection.
•  Recheck each terminal and wire harness for open circuit and poor connection.
•  If wire and connection are ok, intermittent trouble or faulty ecm.
•  Replace the ecm with a known good one, and inspect it again. Refer to “ecm removal and installation” in section 1c .

• Open or short circuit in the w/b wire or o/ w wire.
•  Loose or poor contacts on the ecm coupler or ho2 sensor coupler.