An ultimate guide on how to reset Allison transmission codes (2024)

Transmission codes are combinations of letters and numbers that are used to control certain operations concerning a car transmission. In this article, we will cover how to reset Allison transmission codes to keep your transmission in its initial state.

Allison transmission codes list

There are numerous transmission codes for Allison each of which is responsible for different tasks. Some of the basic codes include;

1. P0700
2. P0701
3. P0702
4. P0703

These codes are mainly associated with the transmission controls and some brake controls, other branches of transmission control also fall under this category.

Allison transmission fault codes list

The table below contains the full list of transmission fault codes in Allison.

How to reset Allison transmission codes

To reset the fault code on an Allison transmission, you have to be sure that you are identifying the right fault. This can be done by briefly driving your car. After locating the fault code, press and hold the MODE button for about 10 to 15 seconds.

While some fault codes are capable of clearing themselves, others require the ignition cycles to clear.

How to get fault codes from Allison transmission

1. To view or get fault codes from Allison transmission, you will need to use an Allison shift selector.
2. Park your vehicle applying brakes in the process
3. Press the “display mode” button on the shift selector to read the fault codes
4. If the transmission is modified with an oil level sensor, the fluid level indicator will be the first to be displayed
5. The fault code list will be displayed first followed by the subcode list
6. Pressing the MODE button should help you access the next list
7. If an active fault code is present, a LED light will be displayed
8. For an empty code position, a “-“will be displayed in the diagnostic section.

You can watch a video explaining the full process here.

How to read codes on Allison transmission

You can read codes all on the Allison shift selector. If the fluid level of your transmission is normal, the shift selector displays “OL OK” where OL is the oil (fluid) level. If your shift selector reads “OL LO 2” it indicates that the oil level is low, and the number indicates that 2 quarts of transmission fluid are needed to bring the oil level back to its normal state.

Allison transmission code reader

A code reader is called an Allison shift selector. It consists of a MODE button, a MODE indicator, and a diagnostic button. All of these features listed have their use, the MODE button is used to reset codes on the transmission. There are two types of Allison shift selector, single-digit shift selector, and double-digit shift selector, the single-digit shift selector only displays one figure while the double-digit shift selector displays two or more figures.

How to check Allison transmission codes

Fault codes of an Allison transmission can be seen on the shift selector. To know the description of the code, you will need to access the full list of fault codes. After accessing the list, you can look through it to locate the code and know its description.

Duramax Allison transmission code

There are more than 30 transmission codes on the Duramax Allison transmission, each of these codes has its description and control system response. The codes can be checked using a code transmission reader called the shift selector.

P088B Allison transmission code

the P088B transmission code indicates that the oil filter is heavily clogged. this clogging of the oil filter is at a critical stage and if not fixed can be a serious problem to your vehicle.

P088A Allison transmission code

This transmission code indicates that the oil filter is clogged. the difference between this transmission code and the P088B is that this code indicates a mild clogging of the oil filter while the other signals a severe clogging of the oil filter.

Allison transmission code 2215

The 2215 fault code appears when the Allison engine control unit (ECU) does not receive a proper speed signal from the turbine speed sensor. There are three speed sensors in the front transmission and the turbine speed sensor is the middle sensor positioned inside the transmission. This sensor is important to the ECU for proper shifting.

Allison transmission code 2216

This fault code appears when the output speed sensor malfunctions. To fix this code, the DNS (do not shift)automatic transmission should stay on the current gear.

Allison transmission gear P0762

There are several shift solenoids on the transmission that are used to control the transfer of transmission gears and aid the shifting of gears. The P0762 fault code that there is a problem with the shift solenoid C. This solenoid is responsible for directing transmission fluid whose job is to move the right gear.

Allison transmission code P0880

This code is associated with the disappearance of the power control module (PCM) during an engine operation. In this condition, the PCM has failed to retrieve data from the traction control module communication circuit. To fix this code, repair the power relay, blown fuse, or damaged wiring.

Allison transmission code P070C

Usually, the transmission oil level sensor tells the PCM how much fluid is in the transmission, and whenever the PCM detects an inaccurate reading from the transmission fluid level sensor, it reports a P070C code.

Allison transmission code P0726

The car system receives the engine speed signal from the engine speed input circuit. but when the car system receives a non-standard report from the engine speed input circuit, it reports a code P0726. To clear this code, use the standard turbine speed value.

Allison transmission code P0847

This code indicates that there is a low voltage on the circuit that the transmission fluid pressure sensor works on. This sensor relays the amount of hydraulic pressure available to the ECU. To fix this code, you will need to replace some of the electrical components in the transmission and change the transmission fluid.

Allison transmission code P0897

Allison transmission sends in this code when the available transmission fluid is far lower than the manufacturer would recommend. This may prevent gears from shifting and can cause damage to your vehicle. To clear this code, replace the transmission fluid with sufficient fluid.

Alison transmission code P2793

This code appears when there is a fault in the component inside the shifter assembly or by a damaged connector. In some cases, this code can appear due to shorted wires or when the transmission range selector is not properly positioned.

Allison transmission code P0721

When the ECU detects a malfunction with the output shaft sensor (OSS), it sends in this code. The OSS is used by a vehicle to monitor the revolution per minute (RPM) or speed of the transmission output shaft to decide when to carry out gear changes.

Allison transmission code P2789

Vehicles that possess dual-clutch automated manual transmission are likely to receive this code. This happens when the PCM detects unusual activity in the clutch adaptive learning system.

Allison transmission code spn 4177 fmi 17

This code is also known as the transmission oil life monitor and it tells you that the transmission fluid needs to be changed, this is based on how long that specific fluid has been used by the vehicle. It helps the transmission fluid last longer while still protecting the transmission.

P2761 Allison transmission code

This code points out a problem with the main circuit of the pressure control system that lies within the torque converter lock-up clutch (TCC) being in an open region. The TCC creates a direct connection between the engine output and the transmission input by connecting the turbine shaft to the torque converter shell.

U0100 Allison transmission code

This code is generated when there is a loss of connection between the PCM and a specific module. Once his code is triggered, your vehicle will shut down and will be unable to restart until the problem is addressed. This problem is best fixed by an expert.

Allison 4000 transmission diagnostic codes

A diagnostic code is a list containing the most occurring fault codes in a vehicle. The codes in this list have the following information.

1. The code list position
2. The main code
3. The sub code
4. The active indicator
5. The ignition cycle counter
6. The event counter

Conclusion

We have listed out various fault codes associated with Allison transmission, we have also described how to reset Allison transmission codes. Each code has its meaning, cause, control system response, and solution so you must know all about these codes.