How to Check Check Engine/Service Engine Soon Light Codes

By: Nick Zluticky

Without OBD II

On G20 models, the ECU is located behind the center console. On J30, M30 and Q45 models, the ECU is located behind the RH kick panel.

If a malfunction occurs within the ECU/fuel injection system, a diagnostic trouble code may be stored in the ECU and the ‘‘Check Engine’’ lamp will blink. There is also a lamp built into the ECU which will concurrently blink.

To read Code output, proceed as follows:

1. Turn ignition On, but do not start engine.

2. Using a small screwdriver, turn diagnostic mode selector switch, located on side of ECU, fully clockwise.

3. Wait two seconds, then rotate switch to full counterclockwise position.

4. A malfunction code can be read as the long (0.6 second) blink, indicating the first digit of a two digit number and the short (0.3 second) blink, indicating the second digit.

Note: Ensure that the diagnostic switch is to the full counterclockwise position whenever the vehicle is in use.

w/OBD II

On Infiniti's built after 96, connect a suitable Scan Tool to the DLC, located under the instrument panel fuse box cover (driver's left knee).

Clearing Codes

If using a scan tool, follow tool manufacturer’s instructions to clear Codes.

A second, though more time consuming method of clearing codes involves using a small screwdriver to turn the diagnostic mode selector switch, located on the side of the ECM/ECU, fully clockwise. After waiting two seconds, rotate the switch to the full counterclockwise position. The diagnosis will end and memory will then be cleared.

List of Codes

Pre-OBDII

11 Crank Angle Sensor 12 Mass Air Flow Sensor 13 ECT Sensor 14 Vehicle Speed Sensor 16 TCS Signal 21 Ignition Signal Circuit 25 Idle Air Control Valve 22 Fuel Pump Control 31 ECM 32 EGR Function 33 Heated Oxygen Sensor 34 Knock Sensor 35 EGR Temperature Sensor (RH) 41 Intake Air Temperature Sensor 42 Fuel Pump Sensor 43 Throttle Position Sensor 45 Injector Leak 46 Secondary Throttle Sensor 51 Injector Analysis 53 Exhaust Gas Sensor (LH) 54 Signal Circuit From A/T Control Unit To ECM

55 System OK (1990-1995 Q45 only) 65-71 Single Cylinder Or Multiple Cylinder Misfire 72 Three Way catalyst Function 76 Fuel Injection System Function 77 Rear Heated Oxygen Sensor 82 Crankshaft Position Sensor 84 A/T Diagnosis Communication Line 91 Front Heated Oxygen Sensor Heater 103 Park/Neutral Position Switch 105 EGR & Canister Control Solenoid

OBD2 Codes

P0000 No Self Diagnostic Failure Indicated P0100 MAF Sensor P0105 Absolute Pressure Sensor P0110 IAT Sensor P0115 ECT Sensor P0120 TP Sensor P0125 ECT Sensor P0130 Closed Loop, Bank 1 Or Front O2S, Bank 1 P0131 Front O2 Sensor, Bank 1 Lean Shift Monitoring P0132 Front O2 Sensor, Bank 1 Rich Shift Monitoring P0133 Front O2 Sensor, Bank 1 Response Monitoring P0134 Front O2 Sensor, Bank 1 High Voltage P0135 Front HO2S Heater, Bank 1 P0136 Rear O2S, Bank 1 P0137 Rear O2S, Bank 1 Minimum Voltage Monitoring P0138 Rear O2S, Bank 1 Maximum Voltage Monitoring P0139 Rear O2S, Bank 1 Response Monitoring P0140 Rear O2S, Bank 1 High Voltage P0141 Rear H02S Heater, Bank 1 P0150 Closed Loop, Bank 2 Or Front O2S, Bank 2 P0151 Front O2 Sensor, Bank 2 Lean Shift Monitoring P0152 Front O2 Sensor, Bank 2 Rich Shift Monitoring P0153 Front O2 Sensor, Bank 2 Response Monitoring P0154 Front O2 Sensor, Bank 2 High Voltage P0155 Front HO2S Heater, Bank 2 P0156 Rear H02S Sensor, LH Bank P0157–P0160 Rear O2S, Bank 2 P0161 Rear H02S Heater, LH Bank Or Bank 2 P0171 Fuel System Lean, Bank 1 P0172 Fuel System Rich, Bank 1 P0174 Fuel System Lean, Bank 2 P0175 Fuel System Rich, Bank 2 P0180 Tank Fuel Temp Sensor P0300 Random Misfire P0301–P0308 Misfire, Cylinder No. 1–8 P0325 Knock Sensor, Bank 1 P0330 Knock Sensor, Bank 2 P0335 CKP Sensor (Pos) P0340 CMP P0400 EGR System P0402 EGRC/BPT Valve P0403 EGR Volume Control Valve Circuit P0420 TW Catalyst System, Bank 1 P0430 TW Catalyst System, Bank 2 P0440 EVAP Small Leak P0443 Purge Control/V & S/V P0446 Vent Control Valve P0450 EVAP Pressure Sensor P0500 Vehicle Speed Sensor P0505 IACV/AAC Valve P0510 Closed TP Sensor P0600 A/T Comm Line P0605 ECM/ECU P0705 PNP Or Inhibitor Switch P0710 ATF Temp Sensor P0720 VSS A/T P0725 Engine Speed Signal P0731 A/T 1ST Signal P0732 A/T 2ND Signal P0733 A/T 3RD Signal P0734 A/T 4TH Signal Or TCC P0740 TCC SV Solenoid P0744 A/T TCC Signal P0745 Line Pressure S/V P0750 Shift Solenoid/V A P0755 Shift Solenoid/V B P1105 MAP/BARO Switch SOL/V P1110 Intake Valve Timing Control, LH Bank P1120 TP Sensor 2 P1125 Tandem TP Sensor P1130 Swirl Control Valve Control Solenoid Valve P1135 Intake Valve Timing Control, LH Bank 2 P1140 Intake Valve Timing Control Position Sensor, RH Bank 1 P1145 Intake Valve Timing Control Position Sensor, LH Bank 2 P1148 Closed Loop, Bank 1 P1165 Swirl Control Valve Control Vacuum Check Switch P1168 Closed Loop, Bank 2 P1210 Traction Control Signal Circuit P1220 FPCM P1320 Ignition Signal, Primary P1335 CKP Sensor (Ref) P1336 CKP Sensor (POS) Cog P1400 EGRC Solenoid/V P1401 EGR Temp Sensor P1402 EGR System P1440 EVAP Small Leak P1441 VC/V Bypass/V P1443 Canister Control Vacuum Check Switch P1444 Purge Volume Control/V P1445 Purge Volume Control/V P1446 Vent Control Valve P1447 EVAP Purge Flow P1448 Vent Control Valve P1490 VC/V Bypass/V P1491 VC Cut/V Bypass/V P1492 Purge Control/V S/V P1493 Purge Control/V & S/V P1605 A/T Diag Comm Line P1705 TP Sensor A/T P1706 PNP Switch P1760 Overrun Clutch S/V P1900 Cooling Fan