Volt

DTC P1485-P1487

The hybrid powertrain control module 2 (HPCM 2) controls the radiator cooling fans with a pulse width modulated (PWM) signal to the cooling fan control modules. The HPCM 2 supplies a regulated 12 volts to the engine control module (ECM) via the cooling fan output circuit. The ECM modulates the output circuit to ground to request operation of the engine radiator cooling fans in response to predetermined internal combustion engine (ICE) coolant temperatures. The HPCM 2 uses the request from the ECM, along with other inputs such as the need for power electronics, high voltage battery, or HVAC cooling to determine the total percentage of cooling fan operation in a range of 0-100 percent. The ECM cooling fan output circuit is controlled with a solid state device called a driver. The driver is equipped with a feedback circuit which is pulled up to a voltage within the controller. The ECM can determine if the output circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.

The ECM detects that the commanded state of the driver and the actual state of the output circuit do not match for greater than 5 seconds.

DTCs P1485, P1486 and P1487 are type B DTCs.

DTCs P1485, P1486 and P1487 are type B DTCs.

DTCs P1485, P1486 and P1487 will not keep the cooling fans from operating. If one of these DTCs is set the HPCM 2 commands the cooling fans to 90%. If the cooling fans do not operate, refer to Cooling Fan Malfunction - DTC P148A-P148C for further diagnosis.

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Engine running. Observe the DTC information with a scan tool. DTC P1485, P1486, or P1487 should not be set.
2. Observe the scan tool parameters listed below:

•	Cooling Fan Control Circuit Open Test Status

•	Cooling Fan Control Circuit Low Voltage Test Status

•	Cooling Fan Control Circuit High Voltage Test Status

Each of the parameters should display OK or Not Run.

3. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Vehicle OFF, disconnect the X2 harness connector at the K114B HPCM 2.

Note: The cooling fan output circuit is pulled-up to a voltage within the ECM. 3-4 V measured on this circuit with the HPCM 2 harness connector disconnected is normal.

2. Vehicle in Service Mode, test for 3-4 V between the ECM cooling fan output circuit terminal X2-9 and ground.

⇒	If less than the specified range, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.

⇒	If greater than the specified range, test the circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.

3. If all circuits test normal, replace the K114B HPCM 2.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for engine control module or hybrid powertrain control module 2 replacement, programming and setup