Error Code P0880 is defined as Transmission Control Module (TCM) Power Input Signal. This is a generic trouble code, meaning it applies to all vehicles with the OBD-II system, especially those made since 1996 up to the present. This includes vehicles from, but not limited to, Allison, BMW, Chevrolet, Dodge, Hyundai, Jeep, Kia, and Range Rover. However, it seems to be more common among Honda vehicles.

Suppose a vehicle stores the Error Code P0880, accompanied with an activated malfunction indicator lamp (MIL). In that case, that means the PCM (powertrain control module) has determined a problem with the TCM power input circuit. This means the PCM has failed to receive data from the TCM communication circuit. This system allows the engine to calculate the RPM and optimize fuel delivery. The TCM feeds the PCM with input.

While some TCM in OBD-II equipped modules are built into the PCM, most are stand-alone components. When this code is stored, it’s likely that there are other PCM and/or TCM codes present in the vehicle, even Antilock Braking System (ABS) codes as well.

The electronic transmission control system is controlled by control modules (a network of computers). This includes constant communication between the controller area network (CAN) and the various control modules.

The CAN is a system made up of connectors and wirings. It transmits data between the PCM and the TCM, including stored codes. Vehicle speed, transmission input, output speed (RPM), and wheel speed are shared through multiple controllers. These data are used in electronic traction control systems, electronic stability control systems, and anti-lock braking systems.

The PCM uses the input signal from multiple sensors (engine and transmission sensors) to determine the automatic transmission shift strategy. It’s equipped with a high-pressure pump (built within the transmission) to force fluid through the valve body and into the sprag assembly. That’s aside from cooling and lubricating the transmission.

The high-pressure fluid allows the clutches to momentarily separate from the sprag for a smooth gear ratio change. One or more EPC (electronic pressure control) solenoids will also help regulate the fluid pressure. These EP (electronic pressure) sensors provide the PCM the relevant data about the fluid pressure in different transmission points. The electronic shift solenoids will interrupt the high-pressure fluid flow to allow the transmission to shift gears when commanded. Both the transmission input speed sensor and transmission output speed sensor will produce input signals for the PCM to determine the efficiency of the transmission shift.

As with other malfunctions regarding the automatic transmission, an error code that refers to the transmission control system can either be caused by a mechanical or electrical failure. If the PCM determines a malfunction, it will activate the Check Engine light and store the code.

Common Symptoms

  • Disabled electronic traction control
  • Transmission unable to shift
  • The erratic shift pattern in the transmission
  • Disabled ABS

Possible Causes

  • Blown fuse or bad relay (fusible link)
  • Open or shorted CAN circuits
  • Defective vehicle speed sensor
  • Failed mechanical transmission
  • Defective PCM
  • Defective TCM
  • Programming error

How to Check

As with most codes, you need a diagnostic scanner, DVOM (digital volt/ohmmeter), and a reliable vehicle information source that shows how to diagnose the code. An oscilloscope can also help in diagnosing various speed sensors.

You can save time by looking for a TSB (technical service bulletin) that shows similar error code, year, make and model, engine, and symptoms. You may find this info in a vehicle information source.

First, you need to retrieve all the stored codes and the pertinent freeze frame data by connecting the scanner to the diagnostic port of the vehicle. Then, make sure you clear the codes before taking the vehicle for a test drive. One of two things must occur in your test drive; the error code restored, or the PCM enters readiness mode.

The problem is intermittent if the PCM enters readiness mode. This means you may need to wait for the problem to worsen before you can diagnose it accurately. If the code is restored, then you can proceed with your diagnosis.

Use your vehicle information source for the diagnostic flow chart, face views, component locator charts, connector pinout charts, and wirings diagram.

Next, inspect all related connectors and wirings. Replace or repair any damaged components.

Then, test the voltage and ground circuits of TCM or PCM using the DVOM. Also, check the system fuses. Replace any blown or defective fuses, retest as needed.

If there are both voltage and ground at the TCM, test the corresponding circuit at the PCM connector. No voltage means there’s an open circuit between the PCM and the component in question. If there is voltage, you can suspect a programming error or a defective PCM or TCM.

How to Fix

In most cases, the traction control switch is the cause of this code. However, most people are quick to replace the whole traction control module, which is unnecessary. Thus, it is important to thoroughly inspect the traction switch before considering other causes.

Other repairs include:

  • Replacement of bad relay or a blown fuse
  • Repair or replacement of defective speed sensor
  • Repair or replacement of open or shorted circuits in the CAN
  • Repair or replacement of defective PCM or TCM
  • Reprogramming of PCM

The transmission may start to shift harshly when this code is stored.

If the vehicle shows this code, it must be addressed as soon as possible. And since traction control is in problem, it is important to avoid wet, slippery, or rugged surfaces.

This code is usually stored due to a defective contact relay.