Buick Century 2.2L • Century 3.1 L • LeSabre 3.8L • Park Avenue 3.8L Rainier 4.2/5.3L • Regal 3.1L • Regal 3.8L • Rendezvous 3.4/3.5L OBD1 Codes

Model	Year	Engine identification	System
Century 2.2L	1996	VIN Position 8=4	GM
Century 3.1L	1994-05	VIN Position 8=M/J	GM
LeSabre 3.8L	1994-05	VIN Position 8=L/K	GM
Park Avenue 3.8L	1994-05	VIN Position 8=L/K/1	GM
Rainier 4.2L	2004-07	VIN Position 8=S	GM
Rainier 5.3L	2004-07	VIN Position 8=M/P	GM
Regal 3.1L	1996-97	VIN Position 8=M	GM
Regal 3.8L	1994-04	VIN Position 8=L/K/1	GM
Rendezvous 3.4L	2002-05	VIN Position 8=E	GM
Rendezvous 3.5L	2006-07	VIN Position 8=8	GM

General information

Malfunction indicator lamp (MIL) will illuminate or flash if certain faults are recorded.
ECM operates in backup mode if sensors fail, to enable vehicle to be driven to repair shop.

Accessing

Trouble codes can only be displayed by using a Scan Tool connected to the data link connector (DLC).
12 pin connector :
- Century -1995.
- Regal -1995.

16 pin connector f) :
- Century 1996 -.
- LeSabre.
- Park Avenue.
- Rainier.
- Regal 1996-.
- Rendezvous

Erasing

-+ 2000 -method 1 • After the faults have been rectified , the manufacturer recommends that trouble codes are erased by using a Scan Tool connected to the data link connector (OLC). -+2000 -method 2 NOTE: Disconnecting battery ground lead may cause driveabi/ity problems until the engine management system relearns basic values.

Ensure ignition switched OFF for at least 10 seconds.
Disconnect battery ground cable for at least 30 seconds.
Reconnect battery ground cable.
Repeat accessing procedure to ensure no trouble codes remain in ECM fault memory.

NOTE: Disconnecting battery ground lead may also erase memory from electronic units, such as radio. 2001 -+ • After the faults have been rectified, the manufacturer recommends that trouble codes are erased by using a Scan Tool connected to the data link connector (DLC).

Scan code	Fault I.ocation	Probable cause
PO, P2, UO	Refer to OBD-II trouble code tables	–
P1101	Intake air flow -incorrect	Wiring, mechanical fault, engine coolant temperature (EeT) sensor, barometric pressure (BARO) sensor, intake air temperature (IAT) sensor, manifoldabsolute pressure (MAP) sensor, mass air flow (MAF) sensor, throttle position (TP)switch
P1106	Manifold absolute pressure (MAP) sensor circuit intermittent -voltage high	Wiring open circuit/short circuit to positive
P1107	Manifold absolute pressure (MAP) sensor circuit intermittent -voltage low	Wiring open circuit/short circuit to ground
P1111	Intake air temperature (IAT) sensor -circuit intermittent -voltage high	Wiring open circuit/short circuit to positive, ground lead defective
P1112	Intake air temperature (IAT) sensor -circuit intermittent -voltage low	Wiring short circuit to ground
P1114	Engine coolant temperature (ECT) sensorcircuit malfunction -voltage low	Wiring short circuit to ground
P1115	Engine coolant temperature (ECT) sensorcircuit malfunction -voltage high	Wiring open circuit/short circuit to positive, ground lead defective
P1121	Throttle position (TP) sensor -circuit malfunction -voltage high	Wiring open circuit/short circuit to positive, ground lead defective
P1122	Throttle pOSition (TP) sensor -circuitmalfunction -voltage low	Wiring open circuit/short circuit to ground
P1133	Heated oxygen sensor (H02S) 1 -insufficient switching	Wiring open circuit/short circuit to ground, exhaust system leaking, H02S
P1134	Heated oxygen sensor (H02S) 1 -slowresponse	Wiring open circuit/short circuit to ground, exhaust system leaking, H02S
P1137	Heated oxygen sensor (H02S) 2 -signal below threshold (lean)	Wiring open circuit/short circuit to ground, exhaust system leaking, H02S
P1138	Heated oxygen sensor (H02S) 2 -signal above threshold (rich)	Wiring open circuit/short circuit to ground, exhaust system leaking, H02S
P1153	Heated oxygen sensor (H02S) 1, bank 2 insufficient switching	Wiring, oxygen sensor heater, exhaust system leaking, H02S
P1154	Heated oxygen sensor (H02S) 1, bank 2 slow response	Wiring, oxygen sensor heater, exhaustsystem leaking, H02S
P1171	Fuel system -lean during acceleration	Fuel filter, fuel pump, H02S, injectors
P1189	Engine oil pressure warning lamp switchcircuit malfunction	Wiring, engine oil pressure warning lampswitch, ECM
P1200	Injector(s) -circuit malfunction	Wiring open circuit/short circuit to ground! short circuit to positive, ECM
P1257	Boost control problem	Wiring short circuit to ground, hoses blocked/leaking, boost bypass actuator, boost control solenoid, ECM
P1260	Fuel pump speed relay -circuit malfunction	Wiring open circuit/short circuit to ground/ short circuit to positive, fuel pump relay, fuel pump control module, ECM
P1336	Crankshaft position (CKP) sensor -variation not learned	Learning procedure not performed
P1350	Ignition control module (ICM) -electronic spark timing (EST)/ignition control (IC)/bypass circuit malfunction	Wiring open circuit/short circuit to ground!short circuit to positive, ICM, ECM
P1351	Ignition control module, ignition control (I C) circuit -voltage high	Wiring open circuit, ICM, ECM
P1352	Ignition control circuit -bypass line -voltage high	Wiring open circuit, ICM, ECM
P1361	Ignition control module (ICM) -electronicspark timing (EST)/ignition control (IC)/bypass circuit malfunction	Wiring open circuit/short circuit to ground/ short circuit to positive, ICM, ECM
P1362	Ignition control circuit, bypass line -voltage low	Wiring short circuit to ground/short circuit to positive, ICM, ECM
P1374	Crankshaft position (CKP)	Wiring open circuit/short circuit to ground! short circuit to positive, wiring routed near spark plug wires, ignition coils arcing! tracking, ICM, ECM
P1380	Rough road signal -signal error	ABS control module trouble code(s) stored
P1381	Rough road signal -no communication from antilock brake system (ASS) CANdata bus	Wiring open circuit, ABS system
P1400	Cold start emission control -malfunction	Intake/exhaust leak/blockage, mechanicalfault, idle speed control (ISC) system, ignition control, engine coolant temperature (ECT) sensor, H02S
P1403	Exhaust gas recirculation (EGR) valvesolenoid 1	Wiring open circuit/short circuit to ground,exhaust system blocked, EGR valve, ECM
P1404 0	Exhaust gas recirculation (EGR) valvesolenoid 2	Wiring open circuit/short circuit to ground,exhaust system blocked, EGR valve, ECM
P1404 f) D9	Exhaust gas recirculation (EGR) valve -stuck open	Wiring open circuit/short circuit to positive, EGR valve, exhaust system blocked, ECM
P1405	Exhaust gas recirculation (EGR) valve solenoid 3	Wiring open circuit/short circuit to ground, exhaust system blocked, EGR valve, ECM
P1406	Exhaust gas recirculation (EGR) valve position sensor circuit malfunction	Wiring open circuit/short circuit to ground/ short circuit to positive, supply wire, EGR valve, ECM
P1441	Evaporative emission (EVAP) system -leak detected	Wiring short circuit to ground, hose connection(s), EVAP system vacuum switch, EVAP canister purge valve, ECM
P1442	Evaporative emission (EVAP) system vacuum switch -circuit malfunction	Wiring open circuit/short circuit to ground, EVAP system vacuum switch, ECM
P1483	Engine cooling system -performance	Cooling system, engine coolant temperature (ECT) sensor, intake air temperature (IAT) sensor
P1516	Throttle actuator control position -variation between requested and actual throttle position	Wiring open circuit/short circuit, throttle control, ECM
P1520	Park/neutral position (PNP) switch	Wiring short circuit to ground, incorrectly adjusted, ECM
P1530	AlC refrigerant pressure sensor -circuit malfunction	AlC refrigerant pressure, wiring open circuit/ short circuit to ground/short circuit to positive, AlC refrigerant pressure sensor, ECM
P1531	Low AlC refrigerant charge	Low AlC refrigerant charge, wiring opencircuit/short circuit to ground/short circuit to positive, AlC refrigerant low pressure switch, ECM
P1546	AlC compressor clutch relay -circuit malfunction	Wiring open circuit/short circuit to ground/ short circuit to positive, AlC compressor clutch relay, ECM
P1550	Cruise control stepper motor, circuit malfunction	Wiring open circuit/short circuit to positive,cruise control module, ECM
P1554	Cruise control status circuit	Wiring short circuit to ground, cruise control module, ECM
P1558	Cruise control servo position sensor -circuit malfunction	Wiring open circuit/short circuit to groundl short circuit to positive, hoses leaking, cruise control servo, ECM
P1561	Cruise control vent solenoid	Wiring open circuit/short circuit to groundl short circuit to positive, cruise control servo, ECM
P1562	Cruise control vacuum solenoid	Wiring open circuit/short circuit to groundlshort circuit to positive, cruise control servo, ECM
P1565	Cruise control servo position sensor -circuit malfunction	Wiring open circuit/short circuit to groundl short circuit to positive, cruise control servo, ECM
P1567	Cruise control switch -circuit malfunction	Wiring open circuit/short circuit to positive, cruise control switch, brake pedal vacuum valve, ECM
P1568	Cruise control servo -servo position sensor high	Hoses blocked, brake pedal vacuum valve, cruise control servo, cruise control cable binding
P1571	Traction control system (TCS), torquerequest circuit	Wiring open circuit/short circuit to groundlshort circuit to positive, ABS control module trouble code(s) stored, ECM
P1573	Data bus -anti lock brake system (ABS)/ traction control system (TCS)	Wiring, ABS control module trouble code(s) stored
P1575	Brake pedal position (BPP) switch -extended travel	Wiring short circuit to positive, BPP switch, ECM
P1585	Cruise control system -inhibit output circuit	Wiring open circuit/short circuit to groundlshort circuit to positive, supply wire, cruise control motor/actuator, ECM
P1599	Cruise control -power management mode	Hoses blocked, brake pedal vacuum valve, cruise control servo, cruise control cable binding
P1600	Engine control module (ECM) -programming/ memory	ECM
P1602	CAN data bus -antilock brake system (ABS)/ traction control system (TCS)	Wiring, ABS control module trouble code(s) stored
P1604	CAN data bus	Wiring, BCM trouble code(s) stored
P1605	CAN data bus -AlC	Wiring, AlC system trouble code(s) stored
P1610	CAN data bus -body control module (BCM)	Wiring, BCM trouble code(s) stored
P1619	Engine oil life monitor reset switch -circuit malfunction	Wiring short circuit to ground, engine oil life monitor reset switch, ECM
P1621	Engine control module (ECM) -programmingl memory	ECM
P1623	Engine control module (ECM) -PROM	Insecure PROM, ECM
P1626	Data bus, immobilizer	Wiring, BCM trouble code(s) stored
P1626	Immobilizer control module -fuel enablesignal	Incorrect ignition key, wiring open circuit!short circuit to ground/short circuit to positive, immobilizer control module, ECM
P1627	Engine control module (ECM) -programming! memory	ECM
P1629	Immobilizer control module -fuel enable signal	Incorrect ignition key, wiring open circuit/ short circuit to ground/short circuit to positive, immobilizer control module, ECM
P1630	Battery voltage too highllow	Wiring, alternator, ECM
P1630	Engine control module (ECM), immobilizercode learning mode	Immobilizer code not programmed
P1631	Engine control module (ECM) -incorrect immobilizer code	Incorrect key, immobilizer code not programmed
P1633	Engine control module (ECM), ignition supply voltage	Fuse, ECM
P1634	Engine control module (ECM), ignition supply voltage	Fuse, wiring, ECM
P1635	Sensor supply voltage -circuit A malfunction	Wiring, TP sensor, MAP sensor, EGR valve, ECM
P1637	Alternator ‘L’ terminal, circuit malfunction	Wiring, alternator, ECM
P1639	Sensor supply voltage -circuit Bmalfunction	Wiring short circuit to ground/positive, ground wiring open circuit, AlC refrigerant pressure sensor, ECM
P1640	Engine control module (ECM) quad driver! output driver	Wiring, ECM controlled components, ECM ~
P1641	Malfunction indicator lamp (MIL) -circuit malfunction	Wiring open circuit/short circuit to groundl short circuit to positive, MIL, supply wire, ECM
P1641/td>	AlC compressor clutch relay -circuitmalfunction	Wiring open circuit!short circuit to positive, supply wire, AlC compressor relay, ignition main relay, ECM
P1643	Fuel pump control module -circuitmalfunction	Wiring open circuit!short circuit to ground/ short circuit to positive, fuel pump control module, ECM
P1644	Traction control system (TCS) -delivered torque signal out of range	Wiring open circuit/short circuit to groundl short circuit to positive, ECM
P1645	Supercharger (SC) control valve solenoid -circuit malfunction	Wiring open circuit/short circuit to groundl short circuit to positive, SC control valve solenoid, ECM
P1646	Supercharger (SC) control valve solenoidcircuit malfunction	Wiring open circuit/short circuit to ground! short circuit to positive, SC control valve solenoid, ECM
P1650	Engine control module, quad driver/output driver	Wiring, ECM controlled components, ECMiI!l
P1651	Engine coolant blower motor relay 1 -circuit malfunction	Wiring open circuit/short circuit to groundl short circuit to positive, supply wire, engine coolant blower motor relay 1, ECM
P1652	Engine coolant blower motor relay 2 -circuit malfunction	Wiring open circuit/short circuit to groundl short circuit to positive, supply wire, engine coolant blower motor relay 2, ECM
P1653	Traction control system (TCS) -delivered torque circuit	Wiring open circuit/short circuit to ground!short circuit to positive, ABS control module trouble code(s) stored, ECM
P1654	NC compressor clutch relay -circuit malfunction	Wiring open circuit/short circuit to groundlshort circuit to positive, supply wire, AlCcompressor clutch relay, ECM
P1655	Evaporative emission (EVAP) canister purge valve -circuit malfunction	Wiring open circuit/short circuit to ground! short circuit to positive, supply wire, EVAPcanister purge valve, ECM
P1660	Engine control module (ECM) quad driver/output driver	Wiring, ECM controlled components, ECMiI!l
P1662	Cruise control inhibit circuit -circuit malfunction	Wiring open circuit/short circuit to ground,cruise control motor/actuator, cruise control module, ECM
P1663	Alternator warning lamp -circuit malfunction	Wiring open circuit/short circuit to ground! short circuit to positive, supply wire, instrument panel, ECM
P1665	Evaporative emission (EVAP) canister vent valve -circuit malfunction	Wiring open circuit/short circuit to groundl short circuit to positive, supply wire, EVAPcanister vent valve, ECM
P1667	Fuel pump control module -circuit malfunction	Wiring open circuit/short circuit to groundl short circuit to positive, supply wire, fuel pump control module, ECM, fuel pump relay
P1668	Altemator ‘L’ terminal -circuit malfunction	Wiring, voltage regulator, alternator, ECM
P1670	Engine control module (ECM) quad driver! output driver	Wiring, ECM controlled components, ECMiI!l
P1671	Malfunction indicator lamp (MIL) -circuit malfunction	Wiring open circuit/short circuit to groundl short circuit to positive, supply wire, ECM
P1672	Engine oil level warning lamp -circuit malfunction	Wiring open circuit/short circuit to groundl short circuit to positive, supply wire, ECM
P1673	Engine coolant ‘hot’ warning lamp -circuit malfunction	Wiring open circuit/short circuit to ground, cooling system, ECM
P1674	Tachometer -circuit malfunction	Wiring open circuit/short circuit to ground! short circuit to positive, instrument panel,ECM
P1675	Evaporative emission (EVAP) canister ventvalve -circuit malfunction	Wiring open circuit/short circuit to ground, EVAP canister vent valve, ECM
P1676	Evaporative emission (EVAP) canister purge valve -circuit malfunction	Wiring open circuit/short circuit to groundlshort circuit to positive, supply wire, EVAP canister purge valve, ECM
P1680	Engine control module (ECM) -programmingl memory	ECM
P1681	Engine control module (ECM) -programming/ memory	ECM
P1682	Engine control module (ECM) -ignitionpower supply less than 10 V	Wiring, ECM
P1683	Engine control module (ECM) -programmingl memory	ECM
P1689	Traction control system (TCS) -deliveredtorque ‘ output circuit	Wiring open circuit/short circuit to groundlshort circuit to positive, supply wire, ABS trouble codes stored, ECM

Depending on model, year and equipment level, the following components may be connected to this circuit. Use of the vehicle wiring diagram is recommended to confirm which components are fitted.

A/C compressor clutch relay
A/C condenser blower motor relay
Engine coolant blower motor relay
Engine coolant ‘hot’ warning lamp
Evaporative emission (EVAP) canister purge valve
Exhaust gas recirculation (EGR) solenoid
Malfunction indicator lamp (MIL)
Torque converter clutch (TCC) solenoid
Transmission shift solenoids (SS)
Transmission shift warning lamp (MT)