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. If the PCM detects an excessively low system voltage, DTC P0562 will set.

When the charging system detects a fault, the instrument panel cluster (IPC) displays a message or the charge indicator will light.

Conditions for Running the DTC

    • Engine run time more than 20 seconds and above 1,200 RPM.
    • Vehicle speed above 8 km/h (5 mph).

Conditions for Setting the DTC

The PCM detects an improper voltage below 11 volts for 5 seconds.

Action Taken When the DTC Sets

    • The PCM stores the DTC information into memory when the diagnostic runs and fails.
    • The PCM will store conditions which were present when the DTC set as Failure Records data only.
    • The PCM disables most outputs.
    • The transmission defaults to a predetermined gear.
    • The torque converter clutch (TCC) operation is inhibited.
    • The instrument panel cluster (IPC) displays a message.
    • The malfunction indicator lamp (MIL) will not illuminate.

Conditions for Clearing the DTC

    • The Conditions for Setting the DTC are no longer present.
    • A history DTC will clear after 40 malfunction free ignition cycles.
    • The powertrain control module (PCM) receives the clear code command from the scan tool.

Step

Action

Value(s)

Yes

No

Schematic Reference: Starting and Charging Schematics

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

With the scan tool monitor the Ignition 1 signal voltage in the PCM data list.

Does the scan tool display Ignition 1 signal voltage greater than the specified value?

11 V

Go to Step 4

Go to Step 3

3

Test the ignition feed circuit to the PCM for high resistance or open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 7

Go to Step 5

4

  1. Inspect for poor connections at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  2. If you find a poor connection, repair the condition as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 7

Go to Step 6

5

Repair the ignition feed circuit to the PCM for an open or a short to ground. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 7

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6

Important: The replacement PCM must be programmed. Refer to Powertrain Control Module Programming in Engine Controls 8.1L.

Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls 8.1L.

Did you complete the repair?

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Go to Step 7

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7

  1. Review and record the scan tool Fail Records data.
  2. Clear any DTCs.
  3. Operate the vehicle within the Fail Records conditions as noted.
  4. Using a scan tool, monitor the Specific DTC info for this DTC.

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

--

Go to Step 2

System OK