Circuit Description
The transmission control module (TCM) requires a switched ignition voltage input and a direct battery voltage input.
DTC P0561 is a type C DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0561 System Voltage Unstable
Conditions for Running the DTC
| • | The components are powered and ignition voltage is greater than 9.0 volts and less than 18 volts. |
| • | Engine speed is greater than 400 RPM for 0.5 second. |
Conditions for Setting the DTC
DTC P0561 sets when the TCM detects a large variation in ignition voltage or battery direct voltage. When an ignition or battery direct voltage variation of 4.0 volts or greater is detected for 0.5 second, a fault pending is reported. After 1.0 second of 4.0 volts or greater variation, a DTC is set with a failure response.
Action Taken When the DTC Sets
| • | The TCM does not illuminate the malfunction indicator lamp (MIL). |
| • | The transmission fails to hydraulic default. |
| • | DTC P0561 is stored in TCM history. |
| • | The TCM inhibits torque converter clutch (TCC) engagement. |
| • | The TCM freezes shift adapts. |
Conditions for Clearing the DTC
A scan tool can clear the code from TCM history. The TCM automatically clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
| • | Inspect for aftermarket devices that could affect the operation of the starting and charging systems. |
| • | Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions: |
| - | A bent terminal |
| - | A backed-out terminal |
| - | A damaged terminal |
| - | Poor terminal tension |
| - | A chafed wire |
| - | A broken wire inside the insulation |
| • | When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change. |
| • | You may have to drive the vehicle in order to experience a condition. |
| • | Inspect for the presence of aftermarket accessories, such as a remote starter, etc. Depending on how these aftermarket accessories are installed, they may interfere with the required voltage for proper operation of the transmission. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step observes battery feed.
-
This step observes ignition feed.
-
This step observes accessories for voltage fluctuations.
Step | Action | Value | Yes | No |
|---|---|---|---|---|
Schematic Reference: Automatic Transmission Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
2 |
Important: Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function will erase the data. Does the charge indicator illuminate or the driver information center (DIC) display a charging system message? | -- | Go to Charging System Test | Go to Step 3 |
Is voltage within the specified value? | B+ | Go to Step 4 | Go to Step 5 | |
Is voltage within the specified value? | B+ | Go to Step 7 | Go to Step 6 | |
5 | Test the battery positive voltage circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 10 | Go to Diagnostic Aids |
6 | Test the ignition feed circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 |
Did voltage fluctuate by the specified amount? | 4 V | Go to Step 8 | Go to Step 9 | |
8 | Determine the cause of the accessory voltage drop. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 10 | Go to Diagnostic Aids |
9 |
Important: In most cases, the TCM is not at fault. Investigate thoroughly before replacing the TCM. Replace the TCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 10 | -- |
10 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | Go to Step 11 | Go to Step 2 |
11 | 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? | -- | System OK | |
