GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The DTC P0560 System Voltage diagnostic detects a loss of battery voltage to the control module's keep alive memory circuit. Battery positive voltage is supplied to the powertrain control module (PCM) even when the ignition switch is OFF. The battery positive voltage is used for the PCM keep alive memory and the air-fuel ratio adaptive control memory. If DTC P0560 is set, the PCM will not store any other DTCs.

Conditions for Running the DTC

    • The ignition is ON.
    • DTC P0560 runs continuously once the above condition is met.

Conditions for Setting the DTC

No battery voltage detected at the PCM battery positive voltage circuit for at least 3 seconds.

Action Taken When the DTC Sets

    • The PCM illuminates the malfunction indicator lamp (MIL).
    • The PCM stores the conditions that were present when the DTC set as Freeze Frame data.

Conditions for Clearing the MIL/DTC

    • The PCM turns the MIL OFF on the third consecutive trip cycle during which the diagnostic has run and the fault condition is no longer present.
    • A DTC will clear after 40 consecutive warm-up cycles have occurred without a fault.
    • A DTC can be cleared by using the scan tool Clear Information function.

Test Description

The numbers below refer to the step numbers in the diagnostic table.

  1. The Diagnostic System Check-Engine Controls prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

  2. This step checks whether a DTC P0560 is the result of a hard failure or an intermittent condition.

  3. This step checks for battery positive voltage at the electrical connector of fuse block-underhood. If the EFI fuse was faulty, or if there was no voltage to the fuse, the vehicle would not start and there would be no MIL or serial data communication.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

  1. Perform the scan tool Clear DTC Information function.
  2. Start the engine.
  3. Run the engine to obtain normal operating temperature.

Does DTC P0560 set?

--

Go to Step 3

Go to Intermittent Conditions

3

  1. Turn OFF the ignition.
  2. Disconnect the PCM electrical connector C4.
  3. Measure the voltage of the battery positive voltage circuit with a DMM.

Does the DMM indicate the specified value?

B+

Go to Step 5

Go to Step 4

4

Repair the open in the battery positive voltage circuit between the PCM and the Fuse Block-Underhood. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 6

--

5

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

--

Go to Step 6

--

6

  1. Perform the scan tool Clear DTC Information function.
  2. Start the engine.
  3. Run the engine in order to obtain normal operating temperature.
  4. Check for a DTC P0560.

Is a DTC P0560 present?

--

Go to Step 2

Go to Step 7

7

With a scan tool, observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK