Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

The auxiliary power outlet (APO) switch controls the operation of the hybrid control module (HCM) APO state manager. The APO state manager commands one of 3 states from the starter generator control module (SGCM): APO Off, APO Normal, and APO Continuous. The APO switch is a momentary button, its output signal is an input to an HCM analog channel. Five volts are supplied to the switch. The returned voltage is measured relative to HCM signal ground to determine the switch state. A resistor network in the switch circuitry ensures that shorted high and low states can be diagnosed successfully. There are 2 valid voltage ranges of the return signal, one representing switch open, the other representing switch closed. If the voltage is lower than a threshold, a short low is indicated. Similarly, if the voltage is greater than the short high threshold, a short high is indicated.

The SGCM uses the interlock circuit to monitor the plugs and connectors for hybrid system function. The interlock indicates the state of the connectors in the 120 voltage circuits. In the SGCM, the primary side of the transformer is connected to a low frequency oscillator circuit. When the loop is complete, the shorted secondary reduces the oscillator voltage, and a comparator senses this as a good and complete interlock loop. If the loop is open, the oscillator amplitude increases and the comparator senses this as a problem.

The engine is ON.

Schematic Reference

Cigar Lighter/Power Outlet Schematics

Connector End View Reference

Power Outlet Connector End Views

Electrical Information Reference

1. Ignition OFF, disconnect the Power Maintain Relay.
2. Ignition ON, verify that a test lamp illuminates between the control circuit terminal C2 and ground.

⇒	If the test lamp does not illuminate, test the control circuit for an open/high resistance or a short to ground.

3. Ignition OFF, connect a fused jumper between terminal C2 and A1. Disconnect the harness connector at the Auxiliary Power Outlet (APO) switch.
4. Ignition ON, verify that a test lamp illuminates between the APO switch control circuit terminal D and ground

⇒	If the test lamp does not illuminate, test the control circuit for an open/high resistance, or a short to ground. If the circuit tests normal, replace the secondary underhood fuse block.

5. Ignition OFF, remove the fused jumper and reconnect the Power Maintain Relay.
6. Ignition ON, verify that a test lamp illuminates between the APO switch control circuit terminal D and ground.

⇒	If the test lamp does not illuminate, replace the Power Maintain Relay.

7. Ignition ON, verify that a test lamp illuminates between the control circuit terminal D and control circuit terminal C.

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If the test lamp does not illuminate, test the control circuit for an open/high resistance, or a short to voltage between APO switch control circuit terminal C and HCM control circuit terminal 45. If the circuit tests normal or a short to voltage was found and repaired, replace the hybrid control module (HCM).

8. Ignition OFF, verify that a test lamp does not illuminate between battery voltage and APO switch control circuit terminal C.

⇒	If the test lamp illuminates, test the control circuit for a short to ground between terminal C and HCM terminal 45.

9. If all circuits test normal, replace the Auxiliary Power Outlet (APO) switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.