Navistar Diagnostic Trouble Code Index
DTC Codes
| DTC | Circuit | Condition Description |
| 111 | ECM | No errors detected - flash code only |
| 112 | ECM PWR | Electrical system voltage B+ out-of-range high |
| 113 | ECM PWR | Electrical system voltage B+ out-of-range low |
| 114 | ECT | Engine Coolant Temperature signal out-of-range low |
| 115 | ECT | Engine Coolant Temperature signal out-of-range high |
| 121 | MAP | Intake Manifold Absolute Pressure signal out-of-range high |
| 122 | MAP | Intake Manifold Absolute Pressure signal out-of-range low |
| 123 | MAP | Intake Manifold Absolute Pressure signal in-range fault |
| 124 | ICP | Injection Control Pressure signal out-of-range low |
| 125 | ICP | Injection Control Pressure signal out-of-range high |
| 126 | BCP | Engine Brake Control Pressure signal out-of-range low |
| 127 | BCP | Engine Brake Control Pressure signal out-of-range high |
| 131 | APS/IVS | APS signal out-of-range low |
| 132 | APS/IVS | APS signal out-of-range high |
| 133 | APS/IVS | APS signal in-range DTC |
| 134 | APS/IVS | APS signal and IVS disagree |
| 135 | APS/IVS | Idle Validation Switch circuit fault |
| 136 | EFP | Engine Fuel Pressure signal out-of-range low |
| 137 | EFP | Engine Fuel Pressure signal out-of-range high |
| 141 | VVS | Vehicle Speed Sensor signal out-of-range low |
| 142 | VVS | Vehicle Speed Sensor signal out-of-range high |
| 143 | CMP | Incorrect CMP signal signature |
| 145 | CMP | CMP signal inactive |
| 146 | CKP | CKP signal inactive |
| 147 | CKP | Incorrect CKP signal signature |
| 151 | BAP | Barometric Absolute Pressure signal out-of-range high |
| 152 | BAP | Barometric Absolute Pressure signal out-of-range low |
| 153 | WIF | Barometric Absolute Pressure signal out-of-range low |
| 154 | IAT | Inlet Air temperature signal out-of-range low |
| 155 | IAT | Inlet Air temperature signal out-of-range high |
| 161 | MAT | Manifold Air Temperature Signal out-of-range low |
| 162 | MAT | Manifold Air Temperature Signal out-of-range high |
| 163 | EGR | Exhaust Gas Recirculation Valve Position Signal out-of-range low |
| 211 | EOP | Engine Oil Pressure signal out-of-range low |
| 212 | EOP | Engine Oil Pressure signal out-of-range high |
| 215 | VSS | Vehicle Speed Sensor signal frequency out-of-range high |
| 225 | EOP | EOP sensor signal in-range fault |
| 231 | ATA | ATA data communication link error |
| 236 | ELC | ECL switch circuit fault |
| 241 | IPR | Injection Control Pressure regulator OCC self test failed |
| 246 | EFAN | Engine Fan - OCC self test fault |
| 247 | BSV | Engine Brake enable OCC self test failed |
| 251 | IAH | Inlet Air Heater OCC self test failed |
| 256 | RSE | Variable Geometry Turbo control OCC self test failed |
| 267 | ECI | Engine Crank Inhibit OCC self test failed |
| 311 | EOT | Engine Oil Temperature signal out-of-range low |
| 312 | EOT | Engine Oil Temperature signal out-of-range high |
| 313 | EWPS | Engine Oil Pressure below warning level |
| 314 | EWPS | Engine Oil Pressure below critical level |
| 315 | EWPS | Engine speed above warning level |
| 316 | EWPS | Engine Coolant Temperature unable to reach commanded set point |
| 321 | EWPS | Engine Coolant Temperature above warning level |
| 322 | EWPS | Engine Coolant Temperature above critical level |
| 323 | EWPS | Engine Coolant Level below warning/critical level |
| 324 | IST | Idle Shutdown Timer enabled engine shutdown |
| 325 | EWPS | Power reduced, matched to cooling system performance |
| 331 | ICP SYS | Injection Control Pressure above system working range |
| 332 | ICP | Injection Control Pressure above spec. with engine not running |
| 333 | ICP SYS | Injection Control Pressure above/below desired level |
| 334 | ICP SYS | ICP unable to achieve setpoint in time (poor performance) |
| 335 | ICP SYS | ICP unable to build pressure during cranking |
| 341 | EBP | Exhaust Back Pressure signal out-of-range low |
| 342 | EBP | Exhaust Back Pressure signal out-of-range high |
| 343 | AMS | Excessive exhaust back pressure (gauge) |
| 344 | EBP | Exhaust back pressure above spec. when engine off |
| 345 | AMS | Faults detected during VGT portion of the AMS Test |
| 346 | AMS | Faults detected during EGR portion of the AMS Test |
| 351 | AMS | Change in exhaust back pressure did not occur when expected |
| 353 | AMS | Variable Geometry Turbo control over duty cycle |
| 354 | AMS | Variable Geometry Turbo control under duty cycle |
| 355 | AMS | Variable Geometry Turbo overspeed |
| 361 | AMS | VGT control input (MAP/EBP) above/below desired level |
| 365 | AMS | EGR Valve Position above/below desired level |
| 368 | AMS | EGR driver module/ECM2 communication fault |
| 371 | EFP | Engine Fuel Pressure is above normal operating range |
| 372 | EFP | Engine Fuel Pressure is below normal operating range |
| 421 - 426 | INJ | High side to low side open (cylinder number indicated) |
| 431 - 436 | INJ | High side shorted to low side (cylinder number indicated) |
| 451 - 456 | INJ | High side short to ground or V BAT (cylinder number indicated) |
| 523 | IDM | IDM V IGN voltage low |
| 525 | IDM | IDM fault |
| 533 | IDM | IDM relay voltage high |
| 534 | IDM | IDM relay voltage low |
| 543 | ECM/IDM | ECM/IDM communications fault |
| 546 | ECM/IDM | Engine Brake Control Pressure is below expected range |
| 547 | ECM/IDM | Engine Brake Control Pressure is above expected range |
| 551 | ECM/IDM | IDM/CMPO signal inactive |
| 552 | ECM/IDM | IDM incorrect CMPO signal signature |
| 553 | ECM/IDM | IDM CKPO signal inactive |
| 554 | ECM/IDM | IDM incorrect CKPO signal signature |
| 613 | ECM | ECM/IDM software not compatible |
| 614 | ECM | EFRC/ECM configuration mismatch |
| 621 | ECM | Engine using mfg. default rating |
| 622 | ECM | Engine using field default rating |
| 623 | ECM | Invalid Engine Family Rating Code (EFRC) |
| 624 | ECM | Field default active |
| 626 | ECM/PWR | Unexpected reset fault |
| 631 | ECM | Read Only Memory (ROM) self test fault |
| 632 | ECM | Random Access Memory (RAM) - CPU self test fault |
| 655 | ECM | Programmable parameter list level incompatible |
| 661 | ECM | RAM programmable parameter list corrupt |
| 664 | ECM | Calibration level incompatible |
| 665 | ECM | Programmable parameter memory content corrupt |