Chart C-16 PCM Controlled Lamps Circuit Check

Powertrain Control Module Controlled Lamps Diagnostic Chart:

Powertrain Control Module Controlled Lamps Circuit:

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) controlled lamps are powered through the IGN 1 fuse. The PCM turns "ON" the bulb, LED, or driver info center indicator by supplying a path to ground through the PCM.

CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Checks the ability of the PCM to turn the lamp(s) "ON" and ensures that lamp driver circuit(s) are not open.
2. Ensures that the PCM can turn the lamp(s) "OFF" and that the driver circuit(s) are not shorted to ground.
3. Checks for a faulty Instrument Panel Cluster/Driver Information Center (IPC/DIC).


DIAGNOSTIC AIDS
A PCM controlled lamp "ON" at all times most likely indicates that a condition is present which requires the attention of the vehicle operator. Conditions which will illuminate each lamp are as follows:
^ Temperature warning lamp will be illuminated when engine coolant temperature rises above 124°C (250°F). The PCM will turn the temperature warning lamp "OFF" when engine coolant temperature decreases to below 121 °C (250°F).
^ Charging system warning lamp will be illuminated if system voltage falls below 10.6 volts. It will be turned "OFF" when system voltage rises to above 11 volts.
^ Change oil soon lamp will be illuminated when the PCM has determined that the engine oil is near the end of its useful life or a problem exists in the oil life monitor reset circuit. Diagnostic Trouble Code (DTC) P1619 set. The lamp will be turned "OFF" when the oil life monitor is reset or the problem causing DTC P1619 is repaired.
^ Cruise lamp will be illuminated when the vehicle is being operated in cruise control.