Without OBD II

On many nissan and infinity models, the ecu contronl module computer cna be found under the dashboard on the passenger side kick panel. 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 problem occurs in the ECU/fuel injection system, a diagnostic trouble code may be stored in the ECU and the ‘‘Check Engine’’ lamp will blink ro stay solid. Theres also a lamp built into the ECU which will concurrently blink but not on all model, I have a 1996 Nissan 300zx and it doesn't have a led light to indicate this. To get the code, do this:

Turn ignition On, but do not start engine.

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

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

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.

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


On G20 and I30 models, connect a suitable Scan Tool to the DLC, located under instrument panel fuse box cover.

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.

Here is a list of codes to check with:

P0100 - MAF Sensor

P0110 - IAT Sensor

P0115 - ECT Sensor

P0120 - TP Sensor

P0125 - ECT Sensor

P0130 - Front HO2S RH Bank

P0135 - Front HO2S Heater RH Bank

P0136 - Rear HO2S RH Bank

P0141 - Rear HO2S Heater RH Bank

P0150 - Front HO2S LH Bank

P0155 - Front HO2S Heater LH Bank

P0156 - Rear HO2S LH Bank

P0161 - HO2S Heater LH Bank

P0171 - Fuel Injection System Lean RH Bank

P0172 - Fuel Injection System Rich RH Bank

P0174 - Fuel Injection System Lean LH Bank

P0175 - Fuel Injection System Rich LH Bank

P0180 - Fuel Temperature Sensor

P0300 - Multiple Cylinder Misfire

P0301–P0306 - Misfire Cylinders 1–6

P0325 - Knock Sensor

P0335 - CKP Sensor

P0340 - CMP Sensor

P0400 - EGR Function

P0420 - TWC Function

P0430 - TWC Function

P0443 - EVAP Canister Purge Control Solenoid Valve

P0500 - VSS

P0505 - IACV-AAC Valve

P0600 - A/T Control & Communication Line

P0605 - ECM-ECCS Control Module

P0705 - PNP Switch

P1150 - Wastegate Valve Control Solenoid Valve

P1155 - Wastegate Valve Control Solenoid Valve

P1160 - Turbocharger Boost Sensor

P1220 - Fuel Pump Control Module

P1320 - Ignition Signal

P1336 - CKP Sensor

P1400 - EGRC Solenoid Valve

P1401 - Temperature Sensor

P1443 - Canister Control Vacuum Check Switch

P1605 - A/T Diagnosis Communication Line

P1900 - Cooling Fan