| Isuzu Codes |
| Trouble Code |
Fault Location |
Probable Cause |
| P1085 | High Pressure Fuel Pump Performance | |
| P1093 | Fuel Rail Pressure Too Low | |
| P1101 | Mass air flow (MAF) and manifold absolute pressure (MAP) sensors – circuit malfunction | Wiring, MAF, MAP, ECM |
| P1106 | Manifold absolute pressure (MAP) sensor – circuiUintermittent voltage high | Wiring, MAP sensor, mechanical fault, ECM |
| P1107 | Manifold absolute pressure (MAP) sensor – circuiUintermittent voltage low | Wiring, MAP sensor, mechanical fault, ECM |
| P1108 | Barometric pressure (BARO) sensor - circuit/voltage high | ECM |
| P1111 | Intake air temperature (IAT) sensor – circuit/ intermittent voltage high | Wiring, IAT sensor, ECM |
| P1112 | Intake air temperature (IAT) sensor – circuiU intermittent voltage low | Wiring, IAT sensor, ECM |
| P1114 | Engine coolant temperature (ECT) sensor- circuiUintermittent voltage low | Wiring, ECT sensor, ECM |
| P1115 | Engine coolant temperature (ECT) sensor- circuit/intermittent voltage high | Wiring, ECT sensor, ECM |
| P1120 | Throttle motor position sensor 1 – circuit malfunction | Wiring open circuit/short circuit to ground/ short circuit to positive, throttle control unit, ECM |
| P1121 | Throttle position (TP) sensor – circuit/ intermittent voltage high | Wiring, TP sensor, mechanical fault, ECM |
| P1122 | Throttle position (TP) sensor – circuit/ intermittent voltage low | Wiring, TP sensor, mechanical fault, ECM |
| P1125 | Throttle position (TP) motor - fail safe mode | Wiring, TP sensor, TP motor, mechanical fault, ECM |
| P1128 | Manifold absolute pressure (MAP) sensor - pressure lower than expected | MAP sensor |
| P1129 | Manifold absolute pressure (MAP) sensor - pressure higher than expected | MAP sensor |
| P1133 | Heated oxygen sensor (HO2S) - RH front (6 cyl) - insufficient switching | Wiring, HO2S, fuel system, fuel pressure, mechanical fault, ECM |
| P1134 | Heated oxygen sensor (HO2S) - RH front - slow operation | Wiring, HO2S, fuel system, fuel pressure, mechanical fault, ECM |
| P1137 | Heated oxygen sensor (H02S) 1/2- voltage incorrect | Wiring, exhaust system leaking, H02S |
| P1138 | Heated oxygen sensor (H02S) 2 – voltage high | Wiring, H02S |
| P1153 | Heated oxygen sensor (HO2S) - LH front - insufficient switching | Wiring, HO2S, fuel system, fuel pressure, mechanical fault, ECM |
| P1154 | Heated oxygen sensor (HO2S) - LH front - slow operation | Wiring, HO2S, fuel system, fuel pressure, mechanical fault, ECM |
| P1167 | Fuel trim, bank 1 – mixture too rich during deceleration | Injectors, fuel pump, fuel pressure, ECM |
| P1169 | Fuel trim, bank 2 – mixture too rich during deceleration | Injectors, fuel pump, fuel pressure, ECM |
| P1171 | Fuel trim – mixture too lean during acceleration | Wiring, H02/H02S, mechanical fault, fuel system, fuel pressure, ECM |
| P1174 | Fuel Trim Cylinder Balance | |
| P1201 | Injector Circuit Open / Shorted Cylinder #1 | |
| P1202 | Injector Circuit Open / Shorted Cylinder #2 | |
| P1203 | Injector Circuit Open / Shorted Cylinder #3 | |
| P1204 | Injector Circuit Open / Shorted Cylinder #4 | |
| P1205 | Injector Circuit Open / Shorted Cylinder #5 | |
| P1206 | Injector Circuit Open / Shorted Cylinder #6 | |
| P1220 | Throttle motor position sensor 2 - circuit malfunction | Wiring open circuit/short circuit to ground/ short circuit to positive, throttle control unit, ECM |
| P1220 . | Throttle motor position sensor 2 – circuit malfunction | Wiring open circuit/short circuit to ground/ short circuit to positive, throttle control unit, ECM |
| P1221 | Throttle motor position sensor 1/2 – signal variation | Wiring, throttle control unit, ECM |
| P1237 | High Fuel Pressure Regulator Circuit Shorted To Ground | |
| P1238 | High Fuel Pressure Regulator Circuit Shorted To Battery | |
| P1239 | High Fuel Pressure System Fault | |
| P1240 | High Fuel Pressure Regulator Circuit Open | |
| P1241 | High Fuel Pressure Regulator Circuit Low Voltage | |
| P1242 | High Fuel Pressure Regulator Circuit High Voltage | |
| P1246 | Low Fuel Pressure Regulator Circuit Malfunction | |
| P1247 | Low Fuel Pressure Regulator Circuit Low Voltage | |
| P1248 | Fuel Pump Relay Control Circuit Open | |
| P1249 | Low Fuel Pressure Sensor Circuit High Voltage | |
| P1250 | Fuel Pump Relay Control Circuit Shorted To Ground | |
| P1253 | VTEC system - malfunction | Wiring, VTEC solenoid, ECM |
| P1258 | Engine coolant – excessive temperature | Wiring, engine coolant blower motor, mechanical fault, ECM |
| P1259 | VTEC system - malfunction | Wiring, VTEC solenoid/pressure switch, ECM |
| P1271 | Accelerator pedal position (APP) sensor 1/2- signal variation | Wiring, APP sensor, ECM |
| P1272 | Accelerator pedal position (APP) sensor 2/3 – signal variation | Wiring, APP sensor, ECM |
| P1273 | Accelerator pedal position (APP) sensor 1/3- signal variation | Wiring, APP sensor, ECM |
| P1275 | Accelerator pedal position (APP) sensor 1 – circuit malfunction | Wiring open circuit/short circuit to ground/ short circuit to positive, APP sensor, ECM |
| P1280 | Accelerator pedal position (APP) sensor 2 – circuit malfunction | Wiring open circuit/short circuit to ground/ short circuit to positive, APP sensor, ECM |
| P1285 | Accelerator pedal position (APP) sensor 3 – circuit malfunction | Wiring, APP sensor, ECM |
| P1290 | Throttle position (TP) motor -forced idle mode | Wiring, APP sensor, TP motor, mechanical fault, ECM |
| P1293 | High Side Open Bank No. 1 | |
| P1295 | Throttle position (TP) motor – power management mode | Wiring, TP sensor, TP motor, MAP sensor, MAF sensor, ECM |
| P1297 | Electrical load sensor - circuit/voltage low | Wiring, electrical load sensor, ECM |
| P1298 | Electrical load sensor - circuit/voltage high | Wiring, electrical load sensor, ECM |
| P1299 | Throttle position (TP) motor – forced engine shut down mode | Wiring, TP sensor, TP motor, MAP sensor, MAF sensor, ECM |
P1300 – P1399 (Ignition system or misfire) | | P1300 | Random misfire | Ignition/fuel/EGR system, MAP sensor, IAC valve |
| P1310 | Ignition control module (ICM) – diagnosis | Wiring, ignition coil(s), ICM, ECM |
| P1311 | Ignition control module (ICM) – ignition coil secondary coil signal, circuit 1 | Wiring, ignition coil(s), ICM, ECM |
| P1312 | Ignition control module (ICM) – ignition coil secondary coil signal, circuit 2 | Wiring, ignition coil(s), ICM, ECM |
| P1326 | Ignition control module (ICM) – combustion quality input signal | Wiring, ignition coil(s), ICM, ECM |
| P1336 | Crankshaft position (CKP) sensor – signal variation | Wiring, CKP sensor, mechanical fault, learning procedure not performed, ECM |
| P1340 | Ignition control module (ICM) – cylinder identification/syncronization | Wiring, ignition coil(s), ICM, ECM |
| P1345 | CKP/CMP signals – signal malfunction | Wiring, CKP/CMP sensor, mechanical fault |
| P1348 | Variable Valve Timing System Fault Bank 1 | |
| P1350 | Variable Valve Timing System Fault Bank 2 | |
| P1351 | Ignition control module (ICM) – signal voltage high | Wiring, ICM, ignition system, mechanical fault, ECM |
| P1359 | Crankshaft position (CKP) sensor - connector disconnection | Wiring |
| P1361 | Ignition control module (ICM) – signal not switching | Wiring, ICM, ignition system, mechanical fault, ECM |
| P1362 | Crankshaft position (CKP) sensor - no signal | Wiring, CKP sensor, ECM |
| P1380 | ECM to ABS communication – unusable signal | Wiring, mechanical fault |
| P1381 | ECM to ABS communication – misfire detected | Wiring, mechanical fault |
| P1382 | Camshaft position (CMP) sensor - no signal | Wiring, CMP sensor, ECM |
| P1390 | G-force sensor – intermittent voltage low | Wiring, G-force sensor, mechanical fault, ECM |
| P1391 | G-force sensor – performance | Wiring, G-force sensor, mechanical fault, ECM |
| P1392 | G-force.sensor – voltage low | Wiring, G-force sensor, mechanical fault, ECM |
| P1393 | G-force sensor – voltage high | Wiring, G-force sensor, mechanical fault, ECM |
| P1394 | G-force sensor – intermittent voltage high | Wiring, G-force sensor, mechanical fault, ECM |
P1400 – P1499 (Emission control) | | P1400 | Cold start emission control – malfunction | Intake/exhaust leak/blockage, mechanical fault, idle speed control (ISC) system, ignition control, engine coolant temperature (ECT) sensor, H02S |
| P1404 | Exhaust gas recirculation (EGR) valve – stuck open | Wiring open circuit/short circuit to positive, exhaust gas recirculation (EGR) valve position sensor, EGR solenoid |
| P1406 | Exhaust gas recirculation (EGR) system – circuit problem | Wiring, EGR valve/solenoid/position sensor, mechanical fault, ECM |
| P1415 | Secondary air injection (AIR) system, bank 1 | Wiring, hoses blocked/leaking, AIR valve |
| P1416 | Secondary air injection (AIR) system, bank 2 | Wiring, hoses blocked/leaking, AIR valve |
| P1441 | Evaporative emission (EVAP) canister purge system – leak detected | Wiring, EVAP valve/solenoid, hoses, mechanical fault |
| P1442 | Evaporative emission (EVAP) canister purge switch – voltage high | Wiring, EVAP valve/solenoid, hoses, mechanical fault |
| P1456 | Evaporative emission (EVAP) canister purge system (fuel tank system) - leak detected | Hose, fuel tank/pressure sensor, fuel filler cap, EVAP valve/ bypass solenoid, EVAP two way valve, EVAP canister/vent valve |
| P1457 | Evaporative emission (EVAP) canister purge system (canister system) - leak detected | Hose, fuel tank/pressure sensor, EVAP valve/bypass solenoid, EVAP two way valve, EVAP canister/vent valve |
| P1459 | Evaporative emission (EVAP) canister purge system - switch malfunction | Wiring, EVAP flow switch, hose leak/blockage, ECM |
| P1471 | Diesel Particulate Filter Regeneration Insufficient | |
| P1481 | Engine coolant blower motor speed – malfunction | Wiring, engine coolant blower motor, ECM |
| P1482 | Engine coolant blower motor clutch – incorrect voltage | Wiring, engine coolant blower motor relay, engine coolant blower motor, ECM |
| P1484 | Engine coolant blower motor relay – speed signal variation | Wiring, engine coolant blower motor relay, engine coolant blower motor, ECM |
| P1491 | Exhaust gas recirculation (EGR) system - valve lift insufficient | Wiring, EGR valve/position sensor, EGR solenoid, hose leak/blockage, ECM |
| P1498 | Exhaust gas recirculation (EGR) valve position sensor - voltage high | Wiring, EGR valve/position sensor, ECM |
| P1508 | Idle air control (lAC) system – low RPM | Wiring, lAC valve, mechanical fault, ECM |
| P1509 | Idle air control (lAC) system – high RPM | Wiring, lAC valve, mechanical fault, ECM |
| P1512 | Throttle control unit – signal variation | Wiring, throttle control unit, ECM |
| P1514 | Throttle position (TP) sensor/mass air flow (MAF) sensor – signal variation | Wiring, TP sensor, MAP sensor, ECM |
| P1515 | Throttle command/actual throttle position – signal vpriation | Wiring, throttle valve sticking, throttle control unit, ECM |
| P1516 | Throttle position motor – position performance | Throttle valve tight/sticking, TP sensor, wiring, throttle control unit, ECM |
| P1517 | Commanded Versus Actual Throttle Position Correlation | |
| P1518 | Throttle control module/engine control module (ECM) – communication malfunction | Wiring, throttle control module, ECM |
| P1519 | Idle air control (IAC) valve - circuit failure | Wiring, IAC valve, ECM |
| P1520 | Park/neutral position (PNP) switch – circuit malfunction | Wiring, PNP switch, mechanical fault |
| P1521 | Commanded Versus Actual Throttle Position Correlation Small Stop Close | |
| P1523 | Throttle position motor – closed position performance | Throttle valve tight/sticking, TP sensor, wiring open circuit/short circuit to ground, throttle control unit, ECM |
| P1545 | AIC compressor clutch relay – circuit malf!Jnction | Wiring open circuit/short circuit to ground/ short circuit to positive, AJC compressor clutch relay, ECM |
| P1546 | AIC compressor clutch relay – circuit malfunction | Wiring open circuit/short circuit to ground/ short circuit to positive, AJC compressor clutch relay, ECM |
| P1548 | A/C Compressor Clutch Output Circuit Malfunction | |
| P1571 | Brake pedal position (BPP) switch - no operation | Wiring, BPP switch |
| P1574 | Brake pedal position (BPP) switch – circuit malfunction | Wiring, BPP switch |
P1600 – P1699 (ECM – computer output circuit) | | P1600 | Serial communication - malfunction | ECM |
| P1601 | Serial communication – malfunction | ECM |
| P1602 | ECM to ABS communication – circuit malfunction | ECM |
| P1607 | Engine control module (ECM) - internal circuit failure | ECM |
| P1618 | Engine control module (ECM) – internal fault | ECM |
| P1621 | Engine control module (ECM) – internal memory performance | ECM |
| P1625 | Engine control module (ECM) – unexpected reset | Interference from non standard electronics, erase trouble code and re-test |
| P1626 | Immobilizer system – ECM to multifunction control module communicationmalfunction | Wiring, ECM, multifunction control module |
| P1627 | Engine control module (ECM) - analogue/ digital converter | Sensor supply wiring open/short circuit, ECM |
| P1630 | Engine control module (ECM), immobilizer code – learning mode | ECM immobilizer code programming not completed |
| P1631 | Immobilizer system – password/code incorrect | Immobilizer module, incorrect key, mechanical fault, ECM |
| P1632 | Immobilizer system – fueling disabled | !mobilizer module, incorrect key, mechanical fault, ECM |
| P1633 | Engine control module (ECM), ignition supply voltage | Fuse, wiring open circuit, ECM |
| P1635 | Sensor supply voltage - circuit A malfunction | Wiring short circuit to ground/positive, ground wiring open circuit, ECM |
| P1636 | Engine control module (ECM) – RAM stack | Interference from non standard electronics, erase trouble code and re-test |
| P1637 | Alternator ‘L’ terminal – circuit malfunction | Wiring open circuit/short circuit to ground, alternator, battery temperature sensor, ECM |
| P1638 | Alternator field circuit – signal out of range | Wiring, alternator, ECM |
| P1639 | Sensor supply voltage - circuit B malfunction | Wiring short circuit to ground/positive, ground wiring open circuit, throttle position (TP) sensor, ECM |
| P1640 | Engine control module (ECM), output driver 1 – supply voltage high | Wiring, instruments, EVAP canister purge valve, A/C compressor relay |
| P1646 | Sensor supply voltage – circuit C malfunction | Wiring short circuit to ground/positive, ground wiring open circuit, accelerator pedal position (APP) sensor, ECM |
| P1650 | Engine control module quad driver/output driver | Wiring, evaporative emission (EVAP) canister purge valve, intake manifold air control solenoid, ECM |
| P1660 | AT to ECM - data line failure | Wiring, TCM, ECM |
| P1680 | Engine control module (ECM) – malfunction | ECM |
| P1681 | Engine control module (ECM) – malfunction | ECM |
| P1682 | Throttle control module/engine control module (ECM) – ignition power supply variation | Wiring, ECM |
| P1683 | Engine control module (ECM) – malfunction | ECM |
| P1686 | AT to ECM - signal B - voltage low | Wiring, TCM, ECM |
| P1687 | AT to ECM - signal B - voltage high | Wiring, TCM, ECM |
| P1689 | Traction control system (TCS), delivered torque signal – malfunction | Wiring, poor connections, ECM |
| P1705 | AT - gear shift malfunction | Wiring, range position switch, ECM |
| P1706 | AT - gear shift malfunction | Wiring, range position switch, ECM |
| P1738 | Automatic transmission | Wiring, clutch pressure switch 2, ECM |
| P1739 | Automatic transmission | Wiring, clutch pressure switch 3, ECM |
| P1753 | AT - lock-up clutch not engaging/ disengaging | Wiring, lock-up control solenoid A, ECM |
| P1758 | AT - lock-up clutch not engaging | Wiring, lock-up control solenoid B, ECM |
| P1768 | AT - lock-up clutch not engaging | Wiring, linear solenoid, TCM |
| P1773 | AT - lock-up clutch not engaging | Wiring, clutch pressure control solenoid B, ECM |
| P1786 | AT - poor gear shift | Communication wire, ECM |
| P1788 | Automatic Transmission Poor Gear Shift | |
| P1790 | Engine control module (ECM) – AT ROM checksum error | ECM |
| P1791 | AT - lock-up clutch not engaging | Wiring, VSS, TCM |
| P1792 | AT – AT EEPROM checksum error | ECM |
| P1794 | Automatic transmission - BARO signal | Wiring, ECM, TCM |
| P1810 | AT – manual valve position pressure switch malfunction | Wiring, manual valve position pressure switch |
| P1815 | Transmission fluid pressure (TFP) switch – invalid gear selection | Wiring, selector lever linkage incorrectly adjusted, TFP switch, ECM/TCM |
| P1816 | Transmission fluid pressure (TFP) switch – invalid gear selection | Wiring, selector lever linkage incorrectly adjusted, TFP switch, ECM/TCM |
| P1818 | Transmission fluid pressure (TFP) switch – invalid gear selection | Wiring, selector lever linkage incorrectly adjusted, TFP switch, ECM/TCM |
| P1835 | AT- kick-down switch | Wiring, kick-down switch, mechanical fault |
| P1860 | AT- torque converter clutch (TCC) solenoid circuit | Wiring, TCC solenoid |
| P1870 | AT – component slipping | Mechanical fault |
| P1875 | AT – component slipping | Mechanical fault |
| U1000 | Class 2 communication ID not learned | ECM |
| U1026 | 4WD AT control module communication – no signal | Wiring, 4WD AT control module, ECM |
| U1040 | Controller area network (CAN) data bus – communication malfunction | Wiring, instrument panel, ECM |
| U1041 | ECM to ASS communication – no signal | Wiring, ABS control module, ECM |
| U1064 | ECM to multifunction control module communication – no signal | Wiring, multifunction control module, ECM |
| U1096 | ECM to multifunction control module communication – no signal | Wiring, multifunction control module, ECM |
| U1152 | Class 2 communication ID missing | Wiring, missing control module |
| U1300 | Class 2 communication – low voltage | Wiring, ECM |
| U1301 | Class 2 communication – high voltage | Wiring, ECM |
