Circuit Description
The transmission control module (TCM) requires direct battery voltage to operate properly.
DTC P0881 is a type C DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0881 Transmission Control Module (TCM) Power Input Signal Performance
Conditions for Running the DTC
Engine speed is greater than 400 RPM for 0.5 second.
Conditions for Setting the DTC
DTC P0881 sets when the TCM detects a battery direct voltage variation of 4.0 volts or greater for 30 seconds.
Action Taken When the DTC Sets
| • | The TCM does not illuminate the malfunction indicator lamp (MIL). |
| • | Hydraulic default is commanded. Shift selector position and hydraulic state of logic valves determine range. |
| • | The TCM inhibits main modulation. |
| • | The TCM inhibits torque converter clutch (TCC) engagement. |
Conditions for Clearing the MIL/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 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. |
| • | Vehicle accessories imposing a large load on the battery circuit could also cause this DTC to set. |
| • | Loose or corroded battery cables could allow this DTC to set. |
| • | An internal TCM failure, due to a burn up circuit trace, could allow this DTC to set. |
| • | Vehicle charging system failure may cause this DTC to set under certain circumstances. |
| • | A defective vehicle battery may induce this DTC. |
| • | Running the engine with a battery charger attached may cause this DTC to set. |
Test Description
The number below refers to the step number on the diagnostic table.
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. Is voltage within the specified value? | B+ | Go to Diagnostic Aids | Go to Step 3 |
Is voltage within the specified value? | B+ | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 4 | |
4 | Test the battery positive voltage circuit or the engine control module (ECM) B voltage circuit for loose or corroded connectors. Did you find and correct a condition? | -- | Go to Step 6 | Go to Step 5 |
5 |
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 6 | -- |
6 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | Go to Step 7 | Go to Step 2 |
7 | 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 | |
