For 1990-2009 cars

### Circuit Description

The transmission control module (TCM) continuously monitors the system voltage on the Ignition 1 circuits. Lower than normal voltage may be inadequate to operate the transmission control solenoids properly. Improper solenoid operation may cause erratic transmission operation, which may result in internal damage.

When the TCM detects low voltage, DTC P0562 sets. DTC P0562 is a type A DTC.

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0562 System Voltage Low

### Conditions for Running The DTC

• | No engine speed signal DTC P0727

• | No communications DTC U2104 or U0100

• | Trans. Protection Mode is OFF.

• | Transmission input shaft speed is greater than 400 RPM.

### Conditions for Setting The DTC

The TCM detects system voltage is 8.68 volts or less for 20 seconds.

### Action Taken When the DTC Sets

• | The TCM requests the powertrain control module (PCM) to illuminate the malfunction indicator lamp (MIL).

• | The TCM turns the Trans. Protection Mode ON.

• | The transmission will operate in 5th gear when the transmission is shifted into D and 2nd gear when shifted into L.

• | The line pressure is at maximum.

• | The torque converter clutch (TCC) is disabled.

• | The TCM freezes the transmission adaptive functions.

• | The PCM records the operating conditions when the Condition for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.

• | The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.

• | The TCM stores DTC P0562 in TCM history.

### Conditions for Clearing the MIL/DTC

• | The TCM turns OFF the MIL request during the third consecutive trip in which the diagnostic test runs and passes.

• | A scan tool can clear the MIL/DTC.

• | The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.

• | The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.

### Diagnostic Aids

• | Observe the driver information center (DIC) messaging that would indicate the electrical system requires service.

• | Inspect for the following conditions:

- | Loose or damaged terminals at the generator

- | Loose or worn generator drive belt

### Test Description

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

1. This step tests the charging system voltage with a nominal load.

2. This step obtains the ignition voltage measurement reported by the TCM.

3. This step tests the voltage drop from the battery and ignition voltage input at the TCM.

4. This step tests the voltage drop from the ground terminals of the TCM to the ground terminal of the battery.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.

Important:

• | Before clearing the DTC, use the scan tool in order to record the PCM and the TCM Failure Records. Using the Clear Eng./Trans. DTC Info function erases the Failure Records from the powertrain control module (PCM) and the transmission control module (TCM).

• | Using the Clear Eng./Trans. DTC Info function erases stored DTCs in both the PCM and TCM.

3. Record the Failure Records.
4. Clear the DTC.
5. Using the DMM, measure and record the battery voltage across the battery terminals.

Is the voltage higher than the specified value?

11 V

Go to Step 3

Go to Battery Inspection/Test

3 |

1. Start the engine.
2. Allow the engine to warm up to normal operating temperature.

Is the charge indicator light ON?

--

Go to Diagnostic System Check - Vehicle

Go to Step 4

4 |

1. Turn ON the high beam headlamps.
2. Turn the HVAC blower control to the highest speed setting.
3. Turn ON the rear window defroster.
4. Increase the engine speed to 1,500 RPM.
5. Observe the DMM battery voltage and record your voltage reading for reference.

Is the voltage within the specified range?

12.5-14.5 V

Go to Step 5

Go to Charging System Test

5 |

1. Increase the engine speed to 1,500 RPM.
2. Observe the Ignition Voltage with the scan tool.

Is the scan tool Ignition Voltage within the specified range?

12.5-14.5 V

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 6

6 |

1. Turn OFF the ignition.
2. Disconnect the TCM C1 connector.
3. Probe the ignition 1 voltage circuits of the TCM C1 connector with the ground probe of the DMM. Refer to Measuring Voltage .
4. Connect the positive lead of the DMM to the battery positive terminal.
5. Turn ON the ignition, with the engine OFF.

Are the voltage drop measurements less than the specified value?

0.5 V

Go to Step 10

Go to Step 7

7 | Inspect the 10 amp TRANS1 fuse for an open. Refer to Circuit Protection - Fusible Links . Did you find an open fuse? | -- | Go to Step 8 | Go to Step 9
8 | Repair the short to ground in the ignition voltage circuits. Refer to Wiring Repairs . Is the repair complete? | -- | Go to Step 13 | --
9 | Test the ignition voltage circuits for an open or high resistance condition. Refer to Testing for Continuity . Did you find and correct a condition? | -- | Go to Step 13 | Go to Step 10
10 |

1. Turn ON the ignition, with the engine OFF.
2. Connect the negative lead of the DMM to the battery ground terminal.
3. Using the positive probe of the DMM, probe both ground circuits of the TCM C1 connector. Observe and record the voltage measurement. Refer to Measuring Voltage Drop .

Are both of the voltage drop measurements less than the specified value?

0.2 V

Go to Step 12

Go to Step 11

11 | Repair the open or high resistance condition in the TCM ground circuits. Refer to Wiring Repairs . Is the repair complete? | -- | Go to Step 13 | --
12 | Replace the TCM. Refer to Control Module References for replacement, setup, and programming. Is the action complete? | -- | Go to Step 13 | --
13 | 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:

3.1. | Start the engine.

3.2. | Allow the engine to warm up to normal operating temperature.

3.3. | TCM voltage must be between 9-18 volts for 20 seconds.

4. Select Specific DTC.
5. Enter DTC P0562.

Does the DTC reset?

--

Go to Step 2

Go to Step 14

14 | With the scan tool, observe the stored information, capture info and DTC info. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to Diagnostic Trouble Code (DTC) List - Vehicle | System OK