GM Service Manual Online
For 1990-2009 cars only

Object Number: 398642  Size: SF
Automatic Transmission Components
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The TCM continuously monitors the system voltage on two circuits, A828 (terminal 26), and X837 (terminal 54). Circuit A828 is the ignition feed for the TCM. Circuit X837 is the battery feed for the TCM. System voltage that is either abnormally high or abnormally low can adversely affect the transmission electronic components.

When the TCM detects low or high voltage on either circuit, then DTC P0560 will set. DTC P0560 is a type B DTC.

Condition For Running The DTC

The ignition switch is in the RUN position.

Conditions For Setting The DTC

Condition 1:

System voltage is less than 9.0 volts for 2.25 seconds.

Condition 2:

System voltage is greater than 16.0 volts for 2.25 seconds.

Action Taken When the DTC Sets

    • Early production - The TCM illuminates the service transmission lamp (STL) and sends a MIL request to the ECM on the second consecutive drive trip that the diagnostic runs and fails. The ECM then illuminates the MIL.
    • Late production - The TCM flashes the Sport Mode Lamp and sends a MIL request on the second consecutive drive trip that the diagnostic runs and fails. The TCM then illuminates the MIL.
    • The ECM records the operating conditions in the Freeze Frame at the time of the MIL request from the TCM.
    • The transmission operates in the default mode (maximum line pressure, command 4th gear, inhibit TCC, freeze shift adapts).

Conditions for Clearing the MIL/DTC

    • Early production - The TCM turns off the STL as soon as the fault is no longer present.
    • Late production - The TCM stops flashing the sport mode lamp as soon as the fault is no longer present.
    • The ECM turns off the MIL after three consecutive drive trips during which the TCM sends no MIL request.
    • A History DTC clears after forty consecutive warm-up cycles, if no failures are present by this diagnostic or any other emission related diagnostic.
    • The scan tool clears the MIL/DTC.
    • The TCM cancels the DTC default mode actions when the fault no longer exists and the ignition switch is Off long enough in order to power down the TCM.

Diagnostic Aids

Vehicles equipped with Fuel Cap Lamps utilize the Sport Mode lamp to indicate a transmission malfunction. In these vehicles, the Sport Mode Lamp flashes at 200 millisecond intervals when the TCM commands the lamp ON.

Vehicles not equipped with Fuel Cap Lamps are equipped with a dedicated Service Transmission Lamp (STL) on the Instrument Panel Cluster (IPC). The STL illuminates steadily when the TCM commands the lamp ON.

Charging the battery with a battery charger or jump-starting an engine may set this DTC. If DTC sets when operating an accessory, check the circuits that are associated with that accessory for a poor connection or an excessive current draw. Also, check for the following conditions:

    • Loose or damaged terminals at the generator
    • Check the belt for proper tension or wear.

Use the J 35616-A connector test adapter kit for any test that requires probing the TCM harness connector or a component harness connector. Using this kit will prevent damage to the harness connector terminals.

Check for the following conditions:

    • Poor connections at the TCM or at the component. Inspect harness connectors for any backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
        Refer to General Electrical Diagnosis in Wiring Systems for proper procedure.
    • Inspect the wiring harness for damage. If the harness appears to be OK, observe the scan tool while moving any related wiring and connectors. A change in the display may help in order to locate the fault.

Test Description

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

  1. This step tests the charging system voltage.

  2. This step tests the battery voltage input at the TCM.

  3. This step tests the ignition voltage and battery voltage inputs at the TCM.

P0560 System Voltage High/Low

Step

Action

Value(s)

Yes

No

1

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to On-Board Diagnostic System Check

2

  1. Install the Scan Tool .
  2. With the engine OFF, turn the ignition switch to the RUN position.
  3. Important: Before clearing the DTCs, use the Scan Tool in order to record Failure Records. Using the Clear Info function erases the Failure Records from the ECM/TCM.

  4. Record the Failure Records.
  5. Clear the DTCs.
  6. Using the J 39200 digital multimeter (DMM), measure the battery voltage across the battery terminals. Record battery voltage for reference.

Is the voltage higher than the specified value?

10 volts

Go to Step 3

Go to Battery Undercharged or Overcharged Diagnosis

3

  1. Start the engine.
  2. Warm the engine to normal operating temperature.

Is the generator/check engine light ON?

--

Go to Charge Indicator Always On

Go to Step 4

4

  1. Turn the high beam headlamps on and the heater blower motor to the HIGH position.
  2. Increase the engine speed to 1,500 RPM.
  3. Observe the J 39200 DMM battery voltage and record your voltage reading for reference.

Is the voltage within the specified range?

12.5-14.5 volts

Go to Step 5

Go to Generator Assembly Bench Check

5

  1. Increase the engine speed to 1,500 RPM.
  2. Observe the Scan Tool Battery Voltage.

Is the Scan Tool Battery Voltage within the specified range.

12.5-14.5 volts

Go to Diagnostic Aids

Go to Step 6

6

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the TCM connector.
  3. Using the J 39200 DMM, check for battery voltage at terminal 26 of the TCM connector.

Can battery voltage be obtained?

--

Go to Step 8

Go to Step 7

7

Inspect the 10 amp CLAMP 15 fuse for an open.

Was the fuse open?

--

Go to Step 13

Go to Step 15

8

Is the voltage on terminal 26 within the specified amount of the battery voltage recorded in Step 2?

0.5 volts

Go to Step 9

Go to Step 18

9

  1. Turn the ignition switch to the RUN position.
  2. Turn all accessories OFF.
  3. Using the J 39200 DMM, measure the voltage on terminal 54 of the TCM connector.

Can battery voltage be obtained?

--

Go to Step 11

Go to Step 10

10

Inspect the 10 amp FLASHER fuse for an open.

Was the fuse open?

--

Go to Step 14

Go to Step 16

11

Is the voltage on terminal 54 within the specified amount of the battery voltage recorded in Step 2?

1.0 volt

Go to Step 12

Go to Step 17

12

  1. Start the engine.
  2. Turn headlamps on high beam and the heater blower motor to HIGH.
  3. Increase engine speed to 1,500 RPM.
  4. Using the J 39200 DMM, measure the voltage on terminal 54.

Is the voltage within the specified amount of the battery voltage recorded in Step 2?

1.0 volt

Go to Step 20

Go to Step 17

13

Inspect circuit A828 for a short to ground.

Was the condition found?

--

Go to Step 19

--

14

Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics in Wiring Systems for complete circuit distribution.

Inspect circuit X837 for a short to ground.

Was the condition found?

--

Go to Step 19

--

15

Inspect circuit A828 for an open.

Refer to General Electrical Diagnosis in Wiring Systems.

Was the condition found?

--

Go to Step 19

--

16

Inspect circuit X837 for an open.

Refer to General Electrical Diagnosis in Wiring Systems.

Was the condition found?

--

Go to Step 19

--

17

Inspect for a high resistance condition in circuit X837 (BRN).

Was the condition found?

--

Go to Step 19

--

18

Inspect for a high resistance condition in circuit A828 (RED).

Was the condition found?

--

Go to Step 19

--

19

Repair the wiring as necessary.

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 21

--

20

Replace the TCM.

Refer to Transmission Control Module Replacement .

Is the replacement complete?

--

Go to Step 21

--

21

Perform the following procedure in order to verify the repair:

  1. Select DTC.
  2. Select Clear Info.
  3. Operate the vehicle under the following conditions:
  4. • Start the engine.
    • Warm the engine to normal operating temperature.

Is the Scan Tool Battery Voltage greater than 9.5 volts, but lower than 15.5 volts?

--

System OK

Go to Step 1