The table below lists some declined transaction response codes in alphabetical order. These response codes appear in the Find a Transaction module.
| Code | Definition |
| E1 | Not initialized |
| E2 | Unknown device - call |
| E3 | Unknown merchant |
| E4 | Invalid transaction |
| E5 | Device disabled - call |
| E6 | Cannot close batch |
| E7 | Invalid amount |
| OA | Invalid response |
| R1 | Device initialized |
| R2 | Retry later |
| R3 | No response - retry |
| R4 | Please close batch |
| S1 | System problem - retry |
| S2 | System problem 96 - call |
| S5 | Unmatched merchant ID |
| T1 | Initialized tested |
| T2 | Authorize tested |
| V0 | Invalid province code |
| V1 | Invalid license |
| V2 | Account frozen |
| V3 | Call Tellcheck |
| V4 | Lost/Verify ID |
| V5 | Decline/Call |
| V6 | Date of birth (DOB) error |
| V7 | Express activity |
| V8 | Do not accept |
| 00 | Invalid transaction |
| 01 | Unknown error |
| 06 | Invalid expiry date |
| 07 | Invalid response |
| 10 | Invalid transaction |
| 12 | Invalid transaction / Declined |
| 14 | Call bank for authorization |
| 41 | Hold card - call bank |
| 42 | Hold card - call bank |
| 43 | Hold card - call bank |
| 50 | Declined |
| 51 | Declined - Retry - system problem |
| 53 | Invalid transaction |
| 54 | Expired card - Refused - Card not supported |
| 60 | Call bank for authorization |
| 69 | Call bank for authorization |
| 78 | Unable to reverse |
| 81 | Declined - Maximum credit per refund reached - $ limit exceeded |
| 82 | Declined - number of times used exceeded |
| 84 | Declined - customer selected negative file reason |
| 85 | Declined |
| 91 | Issuer offline |