Chart C-8B, Shift Light Check
The shift light indicates the optimum shift point for manual transmission to achieve best fuel economy. The light is controlled by ECM by grounding circuit No. 456.
The ECM uses information from coolant temperature, TPS, VSS and engine RPM to determine when to turn light on.
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- This should not turn on the shift light. If it does, there is a short to ground in circuit No. 456 or a fault in ECM.
- When diagnostic terminal is grounded, the ECM should ground circuit No. 456, and shift light should come on.
- This checks the shift light circuit up to ECM connector. If shift light comes on, ECM connector is faulty, or ECM does not have ability to ground circuit.