GM Service Manual Online
For 1990-2009 cars only
Table 1: Accessory DC Power Control Module Scan Tool Data Parameters
Table 2: Accessory DC Power Control Module Scan Tool Output Controls

The Accessory DC Power Control Module Scan Tool Data Parameters list contains hybrid controls-related parameters. The list is arranged in alphabetical order.

Use the Accessory DC Power Control Module Scan Tool Data Parameters list only after the following is determined:

    • The Diagnostic Trouble Code (DTC) List - Vehicle is completed.
    • No diagnostic trouble codes (DTCs)
    • On-board diagnostics are functioning properly

The scan tool values from a properly running vehicle may be used for comparison with the vehicle you are diagnosing. The Accessory DC Power Control Module Scan Tool Data Parameters list represents values that would be seen on a normally running vehicle.

Important: A scan tool that displays faulty data should not be used. The scan tool concern should be reported to the manufacturer. Use of a faulty scan tool can result in misdiagnosis and unnecessary parts replacement.

Only the parameters listed below are referenced in this service manual for use in diagnosis. If all values are within the typical range described below, refer to Symptoms - Hybrid Controls for diagnosis.

Accessory DC Power Control Module Scan Tool Data Parameters

Parameter

System State

Expected Value

Description

Operating Conditions: Engine Idling/Radiator Hose Hot/Closed Throttle/Park or Neutral/Closed Loop/Accessories OFF, unless otherwise noted

12V Circuit Current

Maximum Accessory Load

Near 150 A

This parameter displays the actual current flow of the low voltage (12V) conversion circuit. The Accessory DC Power Control Module (APM) will stop conversion at current greater than 175A. The parameter display range is 0-255 Amps.

12V Circuit Voltage

Maximum Accessory Load

15.5V

This parameter displays the actual voltage of the low voltage (12V) conversion circuit. The parameter display range is 0-25.5V.

12V Conditions Met

--

Yes

This parameter displays if sufficient battery voltage is available at the accessory DC power control module (APM) 12V conversion circuit to begin high voltage to low voltage power conversion. Yes is displayed when the APM detects the minimum amount of voltage at the 12V conversion circuit necessary to enable low voltage power conversion. The parameter display range is Yes, No.

12V Enable Command

--

On

This parameter displays the commanded state of the low voltage (12V) conversion circuit of the accessory dc power control module (APM). The hybrid powertrain control module (HPCM) commands the APM to perform voltage conversion when conditions are acceptable. On is displayed when the APM has received the low voltage circuit (12V) conversion enable command from the HPCM. The APM converts high voltage (300V) to low voltage (12V) and supplies current on the low voltage (12V) circuit in order to support the 12V electrical system loads and also to charge the accessory battery. The parameter display range is On, Off.

300V Charge Command

--

Off

This parameter displays the commanded state of the high voltage (300V) conversion circuit of the accessory DC power control module (APM). The APM is capable of converting high current, low voltage on the 12V electrical system into high voltage, low current on the 300V electrical system. This process occurs only during the Jump Assist service operation and requires the assistance of an off-vehicle 12V source such as a battery charger. On is displayed when the APM has received the Jump Assist enable command from the hybrid powertrain control module (HPCM) via the scan tool. The parameter display range is On, Off.

42V Circuit Current

Maximum Steering Load

30A

This parameter displays the actual current flow of the intermediate voltage (42V) conversion circuit. The Accessory DC Power Control Module (APM) will stop conversion at current greater than 50A. The parameter display range is 0-255 Amps.

42V Circuit Maximum

--

Varies

This parameter displays the maximum voltage of the intermediate voltage (42V) conversion circuit observed during the current ignition cycle. The parameter display range is 0-255V.

42V Circuit Temperature

--

Near DMCM Coolant Temperature

This parameter displays the temperature of the intermediate voltage (42V) conversion circuit terminal. The parameter display range is -40°C to +215°C (-40°F to +419°F).

42V Circuit Voltage

Maximum Steering Load

42V

This parameter displays the actual voltage of the intermediate voltage (42V) conversion circuit. The parameter display range is 0-255V.

42V Enable Command

--

On

This parameter displays the commanded state of the intermediate voltage (42V) conversion circuit. The hybrid powertrain control module (HPCM) commands the APM to perform voltage conversion when conditions are acceptable. On is displayed when the APM has received the intermediate voltage circuit (42V) conversion enable command from the HPCM. The APM converts high voltage (300V) to intermediate voltage (42V) and supplies current on the intermediate voltage (42V) circuit in order to support the power steering system. The parameter display range is On, Off.

42V Temperature Status

--

OK

This parameter displays the temperature status of the intermediate voltage (42V) conversion circuit. The parameter display range is OK, Power Limit, Overtemp Reduced Performance, Overtemp Shutdown.

APM 300V Circuit Current

--

Varies

This parameter displays the high voltage circuit current. This parameter is in-active during Jump Assist. The parameter display range is 0 to 1638.35 Amps.

APM Heat Plate Temperature

--

Near DMCM Coolant Temperature

This parameter displays the temperature of the electronics cooling surface that is shared by the accessory dc power control module (APM) and the drive motor generator power inverter module assembly (PIM). The parameter display range is -40°C to +215°C (-40°F to +419°F).

APM Set Point

Maximum Accessory Load

Near 100%

This parameter displays the low voltage (12V) conversion circuit output as a duty cycle percentage. The APM receives the Low Voltage (12V) output request from the hybrid powertrain control module (HPCM). The HPCM receives a low voltage (12V) voltage output request from the body control module (BCM). The BCM monitors conditions such as 12 volt battery temperature and current flow and requests a specific voltage be maintained. 100% is displayed when the APM is requested to deliver the maximum possible voltage to the low voltage (12V) circuit. The parameter display range is 0 to 100%.

HPCM 300V Circuit

--

Varies

This parameter displays the high voltage circuit voltage as determined by the hybrid powertrain control module (HPCM). The parameter display range is 0-655.35V.

Accessory DC Power Control Module Scan Tool Output Controls

Output Control

Description

Intermediate Voltage Control

    • The hybrid powertrain control module (HPCM) commands the accessory DC power control module (APM) to convert high voltage (300V) to intermediate voltage (42V).
    • The following control limits apply:
       - The ignition has been turned only to Run and not to Crank this ignition cycle.
       - The vehicle must be in Park/Neutral.
       - PRNDL DTCs must not be present.
       - Vehicle speed must be zero.
    • The 42V is the supply to the power steering control module.

Low Voltage Control

    • The hybrid powertrain control module (HPCM) commands the accessory DC power control module (APM) to convert high voltage (300V) to low voltage (12V).
    • The HPCM commands the APM to maintain between 12.5-15.5V on the 12V circuit.
    • When the ignition is ON and high voltage is enabled, this control has a 10 minute elapsed time limit for the current ignition cycle.

Jump Assist

    • The hybrid powertrain control module (HPCM) commands the accessory DC power control module (APM) to convert low voltage (12V) to high voltage (300V).
    • The APM will draw as much as 80A on the 12V circuit during Jump Assist. An external voltage source (charger) is required.
    • When Jump Assist is enabled and the ignition is turned OFF, this control will continue the conversion operation until one of the following conditions is observed:
       - Jump Assist is complete
       - The ignition is turned to the Run or Crank Position
       - The APM 12V circuit voltage is less than an acceptable amount
    • Follow the Jump Assist service information.