GM Service Manual Online
For 1990-2009 cars only

Object Number: 577260  Size: SF
Engine Controls Components
Generator, PNP, Oil Indicators, and IAC
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The powertrain control module (PCM) monitors system voltage on the PCM ignition feed circuit. If the system voltage is out of tolerance, DTC P0560 will be set. When the conditions that set DTC P0560 are present, operation of some vehicle systems and components may be affected.

Conditions for Running the DTC

Engine speed is more than 650 RPM.

Conditions for Setting the DTC

    •  The system voltage monitored at the PCM ignition feed circuit is less than 9.0 volts or more than 18.0 volts.
    •  The above conditions are met for more than 25 seconds.

Action Taken When the DTC Sets

The PCM stores conditions which were present when the DTC set as Failure Records only. This information will not be stored as Freeze Frame Records.

Conditions for Clearing the MIL/DTC

    • The DTC becomes history when the conditions for setting the DTC are no longer present.
    • The history DTC clears after 40 malfunction free warm-up cycles.
    • The PCM receives a clear code command from the scan tool.

Diagnostic Aids

Inspect for the following conditions:

For complete information and additional diagnostics for the vehicle charging system, refer to Diagnostic System Check - Engine Electrical in Engine Electrical.

Important:  Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

    • Faulty terminal connection--Inspect the harness connectors for the following conditions:
       - Backed-out terminals
       - Improper mating
       - Broken locks
       - Improperly formed or damaged terminals
       - Faulty terminal-to-wire connection--Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
    • A damaged harness--Inspect the wiring harness for damage.
        If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
    • Clean and secure connections at the PCM and the engine grounds.

If the DTC is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set.

Step

Action

Values

Yes

No

1

Did you perform the Powertrain On Board (OBD) System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Is DTC P1635 also set?

--

Go to DTC P1635 5 Volt Reference Circuit

Go to Step 3

3

  1. Start and run the engine above 1000 RPM.
  2. Observe Ignition 1 on the scan tool.

Is Ignition 1 voltage between the specified values?

9.0-18.0V

Go to Step 4

Go to Step 5

4

  1. Review and record the scan tool Failure Records data.
  2. Clear DTC P0560 and operate the vehicle in order to duplicate the Failure Records conditions.
  3. Using a scan tool, monitor Specific DTC info for DTC P0560 until the DTC P0560 test runs.
  4. Note test result.

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

--

Go to Step 5

Go to Diagnostic Aids

5

  1. Install a DMM between the battery terminals.
  2. Monitor the DMM while running the engine above 1000 RPM.

Does the DMM show battery voltage between the specified values?

9.0-18.0V

Go to Step 6

Go to Step 7

6

  1. Load electrical system by turning ON the headlamps and the HVAC high blower.
  2. Monitor the DMM while running the engine above 2000 RPM.

Does the DMM show battery voltage between the specified values?

9.0-18.0V

Go to Step 8

Go to Step 7

7

  1. Turn OFF the ignition and disconnect the generator electrical connector.
  2. Turn ON the ignition.
  3. Connect a DMM to measure voltage between the generator control circuit at the generator harness connector and ground.
  4. Command the GEN L Term ON using the scan tool.

Does the DMM display voltage near the specified value with the GEN L Term commanded on?

5.0V

Go to Step 12

Go to Step 10

8

Compare the Ignition 1 voltage displayed on the scan tool with the actual battery voltage read with the DMM.

Does the scan tool Ignition 1 value closely match the actual value read with the DMM?

--

Go to Diagnostic Aids

Go to Step 9

9

Test the PCM ignition feed circuit for a faulty connection between the ignition switch and the PCM. Refer to Wiring Repairs in Wiring Systems .

Did you find and correct the condition?

--

Go to Step 14

Go to Step 13

10

Test the generator control circuit for an open or a short to ground between the PCM and the generator. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 11

11

Test the generator control circuit for a faulty terminal connection at the PCM. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 13

12

Test the generator control circuit for a faulty terminal connection at the generator. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Diagnostic System Check - Engine Electrical in Engine Electrical

13

Important: : The replacement PCM must be programmed.

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming .

Did you complete the replacement?

--

Go to Step 14

--

14

  1. Clear the DTCs.
  2. Start and run engine above 1000 RPM.
  3. Observe Ignition 1 on the scan tool.

Is Ignition 1 voltage between the specified values?

9.0-18.0V

System OK

Go to Step 2