The P0880: Transmission Control Module (TCM) Power Input Signal code points to a fault in the power input signal of the Transmission Control Module, a critical component for transmission operation. This code likely arises from issues like a failing TCM, wiring problems, or power supply inconsistencies. Addressing this code is crucial for maintaining the vehicle’s transmission health and performance.
P0880 quick overview
| Meaning | P0880: Transmission Control Module (TCM) Power Input Signal |
| Is it serious? | This code is quite serious as it can affect the vehicle’s transmission functionality, potentially leading to shifting issues or transmission failure. |
| Possible causes | – Faulty or failing Transmission Control Module (TCM) – Poor power supply to the TCM – Damaged or corroded wiring and connectors related to the TCM – Faults in related modules such as the PCM – Issues stemming from previous vehicle repairs or accidents |
| How to diagnose? | Check TCM Power Supply: Ensure the TCM is receiving proper power and ground. Inspect Wiring and Connectors: Look for damage, corrosion, or loose connections in the TCM wiring. Test TCM Communication: Use diagnostic tools to verify communication with the TCM. Consider TCM Replacement: If diagnostics suggest TCM failure, consider its replacement. Check Related Modules: Inspect other modules like the PCM for communication issues. Seek Software Updates: Look for any relevant software updates or technical bulletins. Perform Voltage Drop Test: Conduct a voltage drop test on the TCM circuit. Review Vehicle History: Check past vehicle repairs or accidents that might impact the TCM. |
P0880 Meaning
This code means there’s a problem with the electrical signal going to your car’s transmission control unit – basically the computer that manages how your car shifts gears. It’s a pretty important issue because it can lead to your car having trouble shifting or even not being able to drive properly. Fixing it might involve checking the wiring, making sure the transmission’s computer is okay, and sometimes replacing parts. It’s definitely something you’ll want to get checked out to keep your car running smoothly.
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How to fix P0880 – learn from mechanics
I looked into P0880 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.
Case #1: Hyundai
Vehicle Information: 2010 Hyundai Elantra SE 2.0L Electronic
Issue + Repair History:
- Car brought in with transmission code P0880.
- Vehicle had been in a previous accident.
- SNSR2 fuse blows as soon as the key is turned on.
- No shorted or chafed wire found in wiring harness.
- Fuse doesn’t blow when the 60-pin connector for the transmission is disconnected.
Computer Codes & Descriptions:
- P0880: Transmission Control Unit (TCU) Communication Error or TCU Malfunction.
Suggestions to Fix Issue:
- Unplug pulse generators and retest.
- Disconnect the transmission solenoid/valve body connector and check if fuse still blows.
- Check the A/T control relay, which is turned on by the TCM and supplies power to transmission solenoids.
- Investigate if other items share the circuit with the TCU that could be backfeeding and causing the fuse to blow.
Final Fix:
- Replaced the ECM with a rebuilt unit and had the car reprogrammed.
- Resolved the issues with no more check engine light, no more blown fuses, and car shifting fine.
Case #2: GMC
Vehicle Information: 2012 GMC Sierra 2500 HD Denali 6.6L
Issue + Repair History:
- Transmission issues with code P0880 and several U codes.
- Transmission works for a few minutes, then loses power, and gear indicator loses line.
- Dealing with multiple communication loss codes and system errors.
Other OBD2 Codes + Test Results:
- P0880 – TCM Power Input Signal.
- U0198 – Undocumented Code.
- U0101 – Lost Communication with TCM.
- U0106 – Lost Communication with Glow Plug Module.
- U0100 – Lost Communication with PCM/ECM.
- C0561 – System Disabled Information Stored Invalid Serial Data.
Suggestions to Fix Issue:
- Ensure OE belt is used as it can affect system performance.
- Check TCM for issues by monitoring 5-volt reference, power, and ground.
- Make sure the charging system is functioning correctly.
- Consider TCM power supply for P0880 and prioritize P codes before U codes.
- Clear history codes and monitor which ones reset.
- Check for damage or loose connections at ECM and BCM connectors.
- Apply dielectric grease to connectors to prevent terminal fretting.
- Consider issues with the BCM as it acts as a network hub.
Final Fix:
- Tested all relevant codes.
- Found that power was at the module but TCM was faulty.
- Replaced and reprogrammed the TCM.
- After replacement and testing, the vehicle functioned correctly with no issues.
Case #3: GMC
Vehicle Information: 2009 GMC Sierra 2500 HD SLE 6.6L
Issue + Repair History:
- Vehicle experienced “Shift Inhibited, select neutral to reset” warning.
- Unable to engage Drive or Reverse after a short period.
- Only P0880 code found, but issue intermittent and varied in severity.
Other OBD2 Codes + Test Results:
- P0880: TCM Power Input Signal.
Suggestions to Fix Issue:
- Check GM Bulletin PI0310c regarding static electricity from aftermarket belts affecting TCM.
- Investigate ignition switch and NSBU (PRNDL switch) for erratic voltage.
- Apply heat to NSBU box to address potential moisture issues.
- Ensure proper transmission fluid level and condition, as Allison transmissions are sensitive to these factors.
Final Fix:
- Discovered TCM was improperly installed after a front-end collision.
- Replaced the belt and repositioned the TCM correctly according to GM Bulletin PI0310c.
- After these adjustments, the transmission functioned properly without issues.
Case #4: Chevrolet
Vehicle Information: 2009 Chevrolet C4500 Kodiak C4U042 6.6L
Issue + Repair History:
- “Shift Inhibited, select neutral to reset” warning indicator.
- New transmission control module installed, but transmission warning light on and gear position indicator not showing.
- Tech 2 scanner indicates “no comm” with new TCM.
- Original TCM restores communication and gear position indicator functionality.
Related Repair History:
- Original TCM intermittently came out of gear and set U0101 and P0880 codes, suggesting TCM failure.
Other Test Results:
- P0880 – Unable to catch problem as it occurs.
Suggestions to Fix Issue:
- Check GM Bulletin Pio310c.
- Unplug PCM and use a different programming tool, like the Snap-On Pass Thru Pro 2.
- Consider dealer programming with MDI tool and latest calibration updates.
- Use an Allison dealer to get a pre-programmed module for the truck.
- Check B+ and grounds before considering a warranty replacement of TCM.
Final Fix:
- Found that GM bulletin PI0310c was relevant.
- Replaced TCM with a unit flashed at Allison, solving the issue.
- TCM was improperly installed post-collision and needed proper repositioning and a new belt.
Case #5: Chevrolet
Vehicle Information: 2003 Chevrolet Silverado 3500 8.1L
Issue + Repair History:
- No shift and no PRNL reading on dash.
- Check engine and ABS lights on.
- Found several PCM and ABS codes.
- Replaced PRNL switch and connector with no change.
- Unable to communicate with TCM.
- Attempted reflashing all modules, but no resolution.
- Powers and grounds to TCM tested and found good.
- Data lines from TCM to ALDL and other modules tested good.
Related Repair History:
- New PRNL switch and connectors installed.
- New TCM installed.
Other Test Results:
- P0802: Engine Torque Signal Circuit.
- P1571: Traction Control Torque Request Circuit.
- C0055: VSS Circuit.
- U1000: Class 2 Communication Network.
- P0880: TCM Power Input Signal.
Suggestions to Fix Issue:
- Check GM Bulletin Pio310c.
- Inspect the ignition switch for low voltage.
- Replace the TCM with a pre-programmed unit from Allison.
- Check harnesses for damage, especially if the vehicle was previously worked on.
- Verify proper installation and grounding of TCM.
Final Fix:
- Found a corroded section in the battery wire to pin 3 on connector C1 at TCM.
- Replaced the corroded section, which resolved the issues with shifting and communication with TCM.
How to diagnose P0880
I made you an overview of solving this DTC, based on all the advice that was suggested by certified mechanics to address this issue in previously mentioned service cases.
| Advice | Brief Description of Diagnostic Step |
|---|---|
| Check Power and Grounds to TCM | Verify that the Transmission Control Module is receiving proper power and ground. |
| Inspect Wiring and Connectors | Examine all related wiring and connectors for damage, corrosion, or loose connections. |
| Test Communication with TCM | Use diagnostic tools to check if there is proper communication with the TCM. |
| Consider TCM Replacement | If diagnostics point towards a faulty TCM, consider replacing it. |
| Inspect Related Modules | Check other related modules, such as the PCM, for any signs of malfunction or communication issues. |
| Verify Proper TCM Installation | Ensure that the TCM is properly installed and grounded, especially after repairs or collisions. |
| Check for Software Updates | Look for any available software updates or bulletins that might address the P0880 issue. |
| Test Related Circuitry | Check other circuits that may influence TCM performance, such as the ignition circuit. |
| Perform Voltage Drop Test | Conduct a voltage drop test on relevant circuits to identify potential power supply issues. |
| Examine Vehicle History | Review any past repairs or accidents that might affect the TCM or its circuitry. |
Car Diagnostics Training
- Car Electrical basics
- OBD-II scanner basics
- How to use an OBD reader
- Introduction to a Bi-directional Scan tool
- OBD scanner buyer’s guide + discounts
I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko