GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The PCM monitors the system voltage to make sure that the voltage stays within the proper range. Damage to components, and incorrect data input can occur when the voltage is out of range. The PCM monitors the system voltage over an extended length of time. If the PCM detects a system voltage outside an expected range for the calibrated length of time, DTC P0560 will set.

Conditions for Running the DTC

    • System voltage below 11 volts.
    • Engine speed above 1500 RPM.
    • Vehicle speed below 40 km/h (25 mph).

Conditions for Setting the DTC

The PCM detects a system voltage out of range for 2 seconds.

Action Taken When the DTC Sets

    • The PCM will not illuminate the Malfunction Indicator Lamp (MIL).
    • The PCM will command a message to be displayed.
    • The PCM will store conditions which were present when the DTC set as Fail Records data only.

Conditions for Clearing the DTC

    • The PCM will command the message OFF after one trip in which the diagnostic test has been run and passed.
    • The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
    • The DTC can be cleared by using the scan tool Clear DTC Information function.

Step

Action

Value(s)

Yes

No

Schematic Reference: Engine Controls Schematics in Engine Controls - 3.5L

1

Did you perform the Engine Electrical Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - Engine Electrical

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Ignition 1 Signal parameter in the PCM data list .

Does the scan tool indicate that the Ignition 1 Signal parameter is greater than the value specified?

11.0 volts

Go to Step 6

Go to Step 3

3

Measure the voltage at the battery and compare it with the Ignition 1 Signal parameter in the PCM data list.

Are the battery voltage and PCM Ignition 1 readings different by more than the value specified?

0.5 volts

Go to Step 4

Go to Charging System Test

4

Test the battery positive voltage circuit of the PCM for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 7

Go to Step 5

5

Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 7

Go to Step 6

6

Important: The replacement PCM must be programmed. Refer to Powertrain Control Module Programming in Engine Controls - 3.5L.

Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls-3.5L.

Is the action complete?

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Go to Step 7

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7

  1. Review and record the scan tool Fail Records data.
  2. Use the scan tool in order to clear the DTC(s).
  3. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
  4. Using the scan tool, observe the Specific DTC Information for DTC P0560 until the test runs.

Does the scan tool indicate that DTC P0560 failed this ignition?

--

Go to Step 2

System OK