Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1998 Buick Century CustomFACTORY OEM SERVICE PROCEDURE
Engine Performance (3.1L) DTCS
ENGINE PERFORMANCE DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION
| DTC | Description |
|---|---|
| P0101 | MAF SENSOR SYSTEM PERFORMANCE |
| P0102 | MAF SENSOR CIRCUIT LOW FREQUENCY |
| P0103 | MAF SENSOR CIRCUIT HIGH FREQUENCY |
| P0107 | MAP SENSOR CIRCUIT LOW VOLTAGE |
| P0108 | MAP SENSOR CIRCUIT HIGH VOLTAGE |
| P0112 | IAT SENSOR CIRCUIT LOW VOLTAGE |
| P0113 | IAT SENSOR CIRCUIT HIGH VOLTAGE |
| P0117 | ECT SENSOR CIRCUIT LOW VOLTAGE |
| P0118 | ECT SENSOR CIRCUIT HIGH VOLTAGE |
| P0121 | TP SENSOR PERFORMANCE |
| P0122 | TP SENSOR CIRCUIT LOW VOLTAGE |
| P0123 | TP SENSOR CIRCUIT HIGH VOLTAGE |
| P0125 | ECT EXCESSIVE TIME TO REACH CLOSED LOOP |
| P0131 | HO2S CIRCUIT LOW VOLTAGE SENSOR 1 |
| P0132 | HO2S CIRCUIT HIGH VOLTAGE SENSOR 1 |
| P0133 | HO2S CIRCUIT SLOW RESPONSE SENSOR 1 |
| P0134 | HO2S INSUFFICIENT ACTIVITY SENSOR 1 |
| P0135 | HO2S HEATER CIRCUIT SENSOR 1 |
| P0137 | HO2S CIRCUIT VOLTAGE LOW SENSOR 2 |
| P0138 | HO2S CIRCUIT VOLTAGE HIGH SENSOR 2 |
| P0140 | HO2S CIRCUIT INSUFFICIENT ACTIVITY - SENSOR 2 |
| P0141 | HO2S HEATER CIRCUIT SENSOR 2 |
| P0171 | FUEL TRIM SYSTEM LEAN |
| P0172 | FUEL TRIM SYSTEM RICH |
| P0201 | INJECTOR NO. 1 CONTROL CIRCUIT |
| P0202 | INJECTOR NO. 2 CONTROL CIRCUIT |
| P0203 | INJECTOR NO. 3 CONTROL CIRCUIT |
| P0204 | INJECTOR NO. 4 CONTROL CIRCUIT |
| P0205 | INJECTOR NO. 5 CONTROL CIRCUIT |
| P0206 | INJECTOR NO. 6 CONTROL CIRCUIT |
| P0230 | FUEL PUMP CONTROL CIRCUIT |
| P0300 | ENGINE MISFIRE DETECTED |
| P0325 | KNOCK SENSOR MODULE CIRCUIT |
| P0327 | KNOCK SENSOR LOW VOLTAGE |
| P0336 | 24X REFERENCE SIGNAL CIRCUIT |
| P0341 | CAMSHAFT POSITION SENSOR CIRCUIT |
| P0401 | EGR SYSTEM INSUFFICIENT FLOW |
| P0403 | EGR SOLENOID CONTROL CIRCUIT |
| P0404 | EGR SYSTEM PERFORMANCE |
| P0405 | EGR SENSOR CIRCUIT LOW VOLTAGE |
| P0420 | TWC SYSTEM LOW EFFICIENCY |
| P0440 | EVAP SYSTEM |
| P0442 | EVAP CONTROL SYSTEM (SMALL LEAK DETECTED) |
| P0446 | EVAP CANISTER VENT BLOCKED |
| P0452 | FUEL TANK PRESSURE SENSOR LOW VOLTAGE |
| P0453 | FUEL TANK PRESSURE SENSOR HIGH VOLTAGE |
| P0506 | IDLE CONTROL SYSTEM LOW RPM |
| P0507 | IDLE CONTROL SYSTEM HIGH RPM |
| P0530 | A/C REFRIGERANT PRESSURE SENSOR CIRCUIT |
| P0560 | SYSTEM VOLTAGE |
| P0601 | PCM MEMORY |
| P0602 | PCM NOT PROGRAMMED |
| P0705 | TRANSAXLE RANGE SWITCH CIRCUIT |
| P0706 | TRANSAXLE RANGE SWITCH PERFORMANCE |
| P1106 | MAP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE |
| P1107 | MAP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE |
| P1111 | IAT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE |
| P1112 | IAT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE |
| P1114 | ECT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE |
| P1115 | ECT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE |
| P1121 | TP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE |
| P1122 | TP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE |
| P1133 | HO2S INSUFFICIENT SWITCHING SENSOR 1 |
| P1134 | HO2S TRANSITION TIME RATIO SENSOR 1 |
| P1336 | CKP SYSTEM VARIATION NOT LEARNED |
| P1351 | IGNITION CONTROL (IC) CIRCUIT OPEN |
| P1352 | BY-PASS LINE OPEN |
| P1361 | IGNITION CONTROL CIRCUIT NOT TOGGLING |
| P1362 | BY-PASS CIRCUIT SHORTED |
| P1374 | 3X REFERENCE CIRCUIT |
| P1380 | EBCM DTC DETECTED ROUGH ROAD DATA UNUSABLE |
| P1381 | MISFIRE DETECTED NO EBCM/PCM SERIAL DATA |
| P1404 | EGR VALVE PINTLE STUCK OPEN |
| P1441 | EVAP SYSTEM FLOW DURING NON-PURGE |
| P1483 | ENGINE COOLING SYSTEM PERFORMANCE |
| P1554 | CRUISE CONTROL STATUS CIRCUIT |
| P1602 | EBCM/EBTCM SERIAL DATA CIRCUIT |
| P1605 | HVAC SERIAL DATA CIRCUIT (CENTURY ONLY) |
| P1610 | STANDARD BODY MODULE SERIAL DATA CIRCUIT |
| P1626 | THEFT DETERRENT SYSTEM FUEL ENABLE CIRCUIT |
| P1630 | THEFT DETERRENT SYSTEM PCM IN LEARN MODE |
| P1631 | THEFT DETERRENT SYSTEM PASSWORD INCORRECT |
| P1635 | 5-VOLT REFERENCE "A" CIRCUIT |
| P1639 | 5-VOLT REFERENCE "B" CIRCUIT |
| P1641 | A/C RELAY CONTROL CIRCUIT |
| P1642 | CHANGE OIL LIGHT CONTROL CIRCUIT |
| P1651 | FAN 1 RELAY CONTROL CIRCUIT |
| P1652 | FAN 2 RELAY CONTROL CIRCUIT |
| P1653 | FUEL LEVEL OUTPUT CONTROL |
| P1662 | CRUISE CONTROL INHIBIT CIRCUIT |
| P1663 | GENERATOR LIGHT CONTROL CIRCUIT |
| P1665 | EVAP VENT SOLENOID CONTROL CIRCUIT |
| P1671 | MIL CONTROL CIRCUIT |
| P1676 | EVAP PURGE VALVE CONTROL CIRCUIT |
Factory Service Tools
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.