Engine Control System 1A-27 ECM Wiring Diagram (3) Characteristics of Circuit Multiple DTC is generated when several troubles (failures) occur. When multiple sensors or switches share a ground, or an open wiring or short occurs on the share power supply or ground, DTCs with respect to related sensors or switches are displayed. If several DTCs are displayed, it is necessary to inspect the shared power supply or ground for open wiring or short. The harness 1 shown above figure is the power common to the AP sensor and idle up volume, and the harness 2 is a common ground. In the event of open wiring in wire 1 or 2, DTC 24 and 31 are displayed at the same time.
Like this, the case where two or more DTC’s are displayed is the multiple DTC. If multiple DTC24 and 31 are displayed, the power supply wire 1 or ground wire 2 must be checked. AP (Accelerator Position) Sensor 2 1 Idle Up Volume PTO Accelerator Sensor 0.5 0.5 0.5 0.5 0.5 Y/B R/B Y/G G/O Y/R Engine Control Module C6 C14 C10 C11 C3 (ECM) (Sensor Signal Signal Signal (Sensor Ground) Power) LNW21ALF000501-X DTC Sensor actuator (detection item) 24 Accelerator position sensor Connector not connected, harness open wiring, or short, failure of main unit 31 idle up volume