Ground
| Ground |
| Ground |
At grounding point G7P, the ECM is grounded on pins 24 and 25. The ignition discharge module is also grounded at grounding point G7P. The engine will not start without ground.
| Sensor ground |
The crankshaft position sensor, intake manifold pressure sensor, intake air temperature sensor, engine coolant temperature sensor and the throttle position sensor are grounded from ECM pin 67. The leads to the crankshaft position sensor the power lead from the oxygen sensor are also screened from ECM pin 67. The engine will not start without sensor ground.
| Reference ground |
On pin 66 the ECM receives reference ground from the sensor ground lead so that it can measure the engine coolant temperature with particularly great precision. Drivability problems while the engine is warming up will occur if reference ground is not connected to pin 66.
The main instrument uses the sensor ground lead as a reference ground so that it can measure the pressure in the intake manifold with particularly great precision. Pressure cannot be measured if there is no reference ground from the Trionic.
On pin 47 the ECM receives reference ground from grounding point G7S on the engine so that it can measure the voltage from the oxygen sensor with particularly great precision. The malfunction indicator lamp (CHECK ENGINE) in the main instrument lights up if there is no reference ground to pin 47.
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