12 Allison diagnostic codes on file — with the full diagnosis, repair steps, and field insights open to read free, no signup required.
Disclaimer: General reference information for trained, qualified technicians only. Codes and procedures vary by model, serial number and software version. Always follow the manufacturer's service manual and your site's safety procedures. Use at your own risk. Not affiliated with or endorsed by any manufacturer.
Find a Allison code by searching below, or browse the table. Codes on file by system:
| Code | System | Symptom | Full fix |
|---|---|---|---|
| Code 24-12 | Transmission | Trans Locked in Neutral / Shift Inhibited | View fix |
| P0700 | Transmission | Shift Inhibited | View fix |
| P0722 / DTC 22-16 | Speed Sensing | Range Inhibit / Transmission Limp | View fix |
| P0731 / DTC 33-12 | Clutch Ratio | Shift Flare / Stumbles into 1st | View fix |
| P0752 / DTC 52-21 | Shift Solenoid | Stuck in 2nd or 3rd / Range Inhibit | View fix |
| P0842 / DTC 42-12 | Pressure Sensing | Check Trans Light / Harsh Downshifts | View fix |
| P0847 | Pressure Sensing | Check Trans / Shift Range Restricted | View fix |
| P0882 / DTC 13-12 | Power Supply | Key-On Check Trans / Intermittent Neutral | View fix |
| P2714 / DTC 56-22 | Clutch Pressure | Harsh 3-4 Shift / Shift Aborted | View fix |
| SPN 191 FMI 9 | — | Trans Warning. | View fix |
| SPN 191 FMI 9 | Transmission | Trans is in "Limp" (3rd Gear). | View fix |
| SPN 523 FMI 7 | Transmission | Gear Mismatch / Neutral Lock. | View fix |
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