C-8B ~ Shift Light (M/T Only)

Chart C-8B Circuit Diagram:

Diagnostic Chart C-8B Shift Light:

CIRCUIT DESCRIPTION:
The shift light indicates the best transaxle shift point for maximum fuel economy. the light is controlled by the ECM and is turned ON by grounding the ORN/BLU wire. The ECM uses information from the following inputs to control operation:

- Coolant temperature sensor

- Throttle position sensor

- Vehicle speed sensor

- Engine rpm

The ECM uses the measured rpm and the vehicle speed to calculate what gear the vehicle is in. It's this calculation that determines when the light should be turned on.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. This should not turn on the shift light. If the light is on, there is a short in the ORN/BLU wire or a fault in the ECM.

2. This checks the shift light circuit up to the ECM connector, If the shift light illuminates, then the ECM connector is faulty or the ECM does not have the ability to ground the circuit.