Kubota WG1605-E3, Diagnostic Manual

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ECM SYSTEM
WG1605-G-E3,WG1605-L-E3,WG1605-GL-E3, DM
1-214
DTC 1152-Closed Loop Low (LPG)
DTC 1154-Closed Loop Low (NG)
Diagnostic Aids
NOTE
• If any other DTCs are present, diagnose those first.
• Oxygen Sensor Wire - Sensor may be mispositioned contacting the exhaust. Check for short to ground between
harness and sensor and on sensor harness
• Fuel Pressure - System will be rich if fuel delivery pressure is too high to gaseous control system. Check fuel
pressure at the control actuator/valve under all operating conditions.
• System Grounding - ECM and engine must be grounded to the battery with very little resistance allowing for
proper current flow. Faulty grounds can cause current supply issues resulting in many undesired problems.
• If all tests are OK, replace the HO
2
S or UEGO sensor with a known good part and retest.
DTC 1155-Closed Loop Bank 1 High (Gasoline)
Diagnostic Aids
NOTE
• If any other DTCs are present, diagnose those first.
• Oxygen Sensor Wire - Sensor may be mispositioned contacting the exhaust. Check for short to ground between
harness and sensor and on sensor harness
• Vacuum Leaks - Large vacuum leaks and crankcase leaks can cause a lean exhaust condition at light load.
• Injectors - System will be lean if an injector driver or driver circuit fails. The system will also be lean if an injector
fails in a closed manner or is dirty.
• Fuel Pressure - System will be lean if fuel pressure is too low. Check fuel pressure in the fuel rail during key-on,
engine off and during normal operating conditions.
• Air in Fuel - If the fuel return hose/line is too close to the fuel supply pickup in the fuel tank, air may become
entrapped in the pump or supply line causing a lean condition and driveability problems.
• Exhaust Leaks - If there is an exhaust leak, outside air can be pulled into the exhaust and past the O
2
sensor
causing a false lean condition.
• Fuel Quality - A drastic variation in fuel quality may cause the system to be lean including oxygenated fuels.
• System Grounding - ECM and engine must be grounded to the battery with very little resistance allowing for
proper current flow. Faulty grounds can cause current supply issues resulting in many undesired problems.
• If all tests are OK, replace the HO
2
S sensor with a known good part and retest.
DTC 1156-Closed Loop Bank 1 Low (Gasoline)
Diagnostic Aids
NOTE
• If any other DTCs are present, diagnose those first.
• Oxygen Sensor Wire - Sensor may be mispositioned contacting the exhaust. Check for short to ground between
harness and sensor and on sensor harness
• Injectors - System will be rich if an injector driver or driver circuit fails shorted-to-ground. The system will also be
rich if an injector fails in an open.
• Fuel Pressure - System will be rich if fuel pressure is too high. Check fuel pressure in the fuel rail during key-on,
engine off and during normal operating conditions.
• System Grounding - ECM and engine must be grounded to the battery with very little resistance allowing for
proper current flow. Faulty grounds can cause current supply issues resulting in many undesired problems.
• If all tests are OK, replace the HO
2
S sensor with a known good part and retest.
KiSC issued 12, 2016 A