Mechanics

DIAGNOSTIC CODES

1995 Nissan Altima • 4 cylinder 2WD Automatic • 150,000 miles

I just swapped out engines in my 1995 nissan altima and now the check engine light is on?
I ran the diagnostic check and it shows three codes. One is for the mass air flow sensor, one for the knock sensor and the last is the revolution sensor. These were all fine prior to the engine swap. I have changed the mass air flow and the revolution sensors and still get the same codes when I run the diagnostic. Could this be caused by a bad or missing ground wire?
Avatar
Denny1900
December 30, 2010.



Having the actual codes would be more helpful, can you post them? There are several codes for each sensor, and yes bad or missing grounds can cause this, especially the PCM ground, and battery ground.

Merlin2021
Dec 30, 2010.
The codes I have are from the flashing check engine light. They are: 1102
11 long - 2 short
0102
1 long - 2 short
0304
3 long - 4 short

Tiny
Denny1900
Dec 30, 2010.
Use the computer itself to read code not the check engine light! Here's how, then repost your codes please. HOW TO READ NISSAN DIAGNOSTIC CODES

On Nissan applications with the Electronic Concentrated Control System (ECCS), the computer has two light emitting diodes
(LEDS) on the compyuter's case that display diagnostic codes (no flash codes are provided through a Check Engine light).
One LED is red and the other LED is green.

TO ACCESS CODES ON NISSANS WITH ELECTRONIC CONCENTRATED CONTROL SYSTEM (ECCS) UP TO 1994: Place ignition switch in On position. On all models except Pathfinder, Pickup and Van proceed as follows: 1. Turn diagnostic mode selector on computer fully clockwise and wait until inspection lamps flash. Number of flashes
displayed indicates corresponding Mode.

2. Note number of flashes, then immediately turn diagnostic mode selector fully counterclockwise. On Pathfinder, Pickup &
Van, proceed as follows: Turn diagnostic mode selector on computer to the ON position and wait until inspection lamps flash.

Note number of flashes, then immediately turn diagnostic mode selector to the OFF position.

On all models, when ignition switch is turned Off during diagnosis, in each mode, and then turned back on again after power
to the computer has dropped off completely, diagnosis will automatically return to Mode 1.

DIAGNOSTIC MODES: Mode I (Mixture ratio feedback control monitorA): During a closed loop condition, the green inspection lamp turns On when
lean condition is present and goes Off when a rich condition is present. During open loop, the green inspection lamp stays
Off.

Mode II (Mixture ratio feedback control monitor B): During a closed loop condition, the red inspection lamp turns On and Off
simultaneously with the green inspection lamp when mixture ratio is controlled within a predetermined value. During a open
loop condition, the red inspection lamp stays Off. The green inspection lamp function is the same as Mode 1.

Mode III (Self-diagnosis): In this mode the diagnostic trouble code is indicated by both the red and greed inspection lamp.
The red inspection lamp corresponds to units of ten and the green inspection lamp corresponds to units of one.

Mode IV (Switches On/Off diagnosis): During this mode, the inspection lamps monitor switch On/Off condition of the throttle
valve switch, starter switch and vehicle speed sensor.

Mode V (Real time diagnosis): If a malfunction is present during a driving test, the inspection lamps will display the
malfunction condition immediately.

PROCEDURE FOR NISSANS 1995 : 1. Place ignition switch in On position.

2. Turn diagnostic mode selector on computer fully clockwise and wait until inspection lamps flash. Number of flashes
displayed indicates corresponding mode.

3. Note number of flashes, then immediately turn diagnostic mode selector fully counterclockwise.

4. If ignition switch is turned Off during diagnosis, in each Mode, and then turned back on again after power to the computer
has dropped off completely, diagnosis will automatically return to mode.

5. For description of modes, proceed as follows: (Mode 1) With engine stopped, system in bulb check state. With engine running system in malfunction warning state.

(Mode II) With engine stopped, system in self-diagnostic results state. With engine running, system in front 02S monitor
state.

SCAN TOOL PROCEDURE: 1. Place ignition switch in Off position.

2. Connect scan tool to diagnostic connector, located near the center console right hand side cover.

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3. Place ignition switch in On position.

4. Enter the diagnostic program, and perform each diagnostic test mode according to each service procedure.

HOW TO CLEAR CODES: The Malfunction indicator lamp (MIL) stored memory will be erased if a battery terminal is disconnected, or after selecting
Mode III or Mode IV on pre-1995 models, or switching from Mode II to Mode I on 1995-96 models.
Or, a scan tool can be used to erase the codes.

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Merlin2021
Dec 31, 2010.