DETECTED CONDITION | POSSIBLE CAUSE | |
C44/C64 (P0156/ P0130) | HO2 sensor output voltage is not input to ECM during engine operation and running condition. (Sensor voltage < 0.45 V) | HO2 sensor circuit open or shorted to ground. Fuel system malfunction. ECM malfunction. |
C44/C64 (P0161/ P0135) | The heater can not operate so that heater operation voltage is not supply to the oxygen heater circuit. | Battery voltage supply to the HO2 sensor. |
Inspection
Step 1
When indicating C44/P0156 for HO2 sensor #2
When indicating C64/P0130 for HO2 sensor #1
- 1) Turn the ignition switch OFF.
- 2) Check the HO2 sensor for loose or poor contacts.
If OK, then check the HO2 sensor lead wire continuity.
- 3) Disconnect the HO2 sensor coupler.
- 4) Check the continuity between W/G (#1) or W/Bl (#2) wire А and ground.
- 5) Also, check the continuity between W/G (#1) or W/Bl (#2) wire А and B/Br wire В. If the sound is not heard from the tester, the circuit condition is OK.
- 09900-25008: Multi-circuit tester set
- Tester knob indication: Continuity test (•)))
- 6) Disconnect the ECM coupler. (5-37)
- 7) Check the continuity between W/G or W/Bl wire А and terminal 12, 15.
- 8) Also, check the continuity between B/Br wire В and terminal 29.
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 the terminal damage or terminal bend.
- HO2S lead wire continuity: Continuity (•)))
- 09900-25008: Multi-circuit tester set
- 09900-25009: Needle pointed probe set
- Tester knob indication: Continuity test (•)))
Is the continuity OK?
YES | Go to Step 2. (When indicating C44/P0130:) |
NO | W/G or W/Bl wire shorted to ground, or W/G and W/Bl or B/Br wire open. |
- 9) After repairing the trouble, clear the DTC using SDS tool. (5-26)
Step 2
- 1) Connect the ECM coupler and HO2 sensor coupler.
- 2) Warm up the engine enough.
- 3) Measure the HO2 sensor output voltage between W/G or W/Bl wire and B/Br wire, when idling condition.
HO2 sensor output voltage at idle speed:
- 0.4 V and less (+ W/G or W/Bl - − B/Br)
- 4) If OK, then pinch the PAIR hose 1 with a proper hose clamp.
- 5) Remove the fuel tank (6-3) and frame head covers (9-6).
- 6) Measure the HO2 sensor output voltage while holding the engine speed at 3 000 r/min.
HO2 sensor output voltage at 3 000 r/min:
- 0.6 V and more (+ W/G or W/Bl - − B/Br)
- 09900-25008: Multi-circuit tester set
- 09900-25009: Needle pointed probe set
- Tester knob indication: Voltage
Is the voltage OK?
YES | W/G wire or B/Br wire open or shorted to ground, or poor 12, 15 or 29 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. |
NO | Replace the HO2 sensor with a new one. |
- 7) After repairing the trouble, clear the DTC using SDS tool. (5-26)
Step 1
When indicating C44/P0161 for HO2 sensor #2
When indicating C64/P0135 for HO2 sensor #1
- 1) Turn the ignition switch OFF.
- 2) Check the HO2 sensor for loose or poor contacts. If OK, then check the HO2 sensor resistance.
- 3) Disconnect the HO2 sensor coupler and measure the resistance between terminals.
- HO2 heater resistance: 4.0 - 5.5 Ω at 23°C (73.4°F) (White - White)
Note:
- Temperature of the sensor affects resistance value largely.
- Make sure that the sensor heater is at correct temperature.
- 09900-25008: Multi-circuit tester set
- Tester knob indication: Resistance (Ω)
Is the voltage OK?
YES | Go to Step 2. |
NO | Replace the HO2 sensor with a new one. |
- 4) After repairing the trouble, clear the DTC using SDS tool. (5-26)
Step 2
- 1) Connect the HO2 sensor coupler.
- 2) Insert the needle pointed probes to the HO2 sensor coupler.
- 3) Turn the ignition switch ON and measure the heater voltage between W/B wire and ground.
- 4) If the tester voltage indicates the battery voltage, it is good condition.
- Heater voltage: Battery voltage
- (+ W/B - − Ground)
Note: Battery voltage can be detected only before starting the engine.
- 09900-25008: Multi-circuit tester set
- 09900-25009: Needle pointed probe set
- Tester knob indication: Voltage
Is the voltage OK?
YES | 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. |
NO | Open or short circuit in the W/B wire. Loose or poor contacts on the ECM coupler (terminal 41) or HO2 sensor coupler. |
- 5) After repairing the trouble, clear the DTC using SDS tool. (5-26)