Automotive Torque Specifications

Home Nissan Nissan Maxima 1985-91

Nissan Maxima 1985-91

Computer Trouble Codes
Trouble Code Circuit or System Probable Cause
Code 11
(1 red flash, 1 green flash)
Crank angle sensor/circuit Check crank angle sensor for looseness 
or loose connection
Code 12
(1 red flash, 2 green flashes)
Air flow meter/circuit The air flow meter source or ground circuit(s)
may be shorted or open. Check the air flow
meter.
Code 13
(1 red flash, 3 green flashes)
Cylinder head temperature sensor The sensor source or ground circuit(s) may
be shorted or open. Check the temperature
sensor circuit(s).
Code 14
(1 red flash, 4 green flashes)
Vehicle speed sensor The vehicle speed sensor signal circuit is 
open. The repair must be performed by a
dealer service department.
Code 21
(2 red flashes, 1 green flash)
Ignition signal  
Code 22
(2 red flashes, 2 green flashes)
Fuel pump circuit The fuel pump circuit is open or shorted.
Code 23
(2 red flashes, 3 green flashes)
Throttle valve switch circuit The throttle valve switch signal circuit is 
open.
Code 31
(3 red flashes, 1 green flash)
ECU control unit The ECU input signal is beyond "normal" 
range. This repair must be performed by 
a dealer service 
department.
Code 32
(3 red flashes, 2 green flashes)
EGR function
(1989 California models only)
The EGR control valve does not operate.
Code 33
(3 red flashes, 3 green flashes)
Exhaust gas sensor The exhaust gas sensor is open.
Code 34
(3 red flashes, 4 green flashes)
Detonation sensor
(1989 models)
The detonation sensor circuit is open or 
shorted. This repair must be performed 
by a dealer service department.
Code 41
(4 red flashes, 1 green flash)
Fuel temperature sensor
(1987 and earlier models)
The fuel temperature sensor circuit is 
open or shorted.
Code 42
(4 red flashes, 2 green flashes)
Fuel temperature sensor
(1988 models)
The fuel temperature sensor circuit is 
open or shorted.
Code 43
(4 red flashes, 3 green flashes)
Throttle sensor The throttle sensor circuit is open or 
shorted. This repair must be performed 
by a dealer service department.
Code 45
(4 red flashes, 5 green flashes)
Injector leak
(1989 California only)
The injector(s) have fuel leaks.
Code 54
(5 red flashes, 4 green flashes)
A/T Control unit
(1989 models)
There is a short between the A/T Control 
unit and the ECU. This repair must be repaired
 by a dealer service department.
Code 55
(5 red flashes, 5 green flashes)
ECCS Normal operation. This means there is 
nothing wrong.
ECU
Fig. 1 Checking ECU trouble codes.

The ECU contains two lights in the oval slot on the side, as seen in the diagram, a red light and a green light. Red on the left, green on the right. The ECU is located under the passenger seat on earlier models. On later models it is located on the floor board under the dash, just in front of the center consol. It is accessed on the passenger side inner kick panel. To check the codes, turn the ignition switch on, but do not start the engine. Insert a flat bladed screw driver in the hole next to the slot where the two lights are located. Turn the screw counter clockwise all the way. The two lights should start to blink together, first one time, then two times, then three times, and finally four times. When the lights blink the three times together, turn the screw back clockwise all the way. The codes should start blinking, first the red light will blink, then the green light will blink. If the red light blinks 1 time and the green light blinks 2 times, that means code 12. The codes will continue to repeat themselves until you turn the ignition switch off. After making the repair, turn the ignition switch on, insert the screw driver and turn the screw counter clockwise all the way. Both lights will blink together just like before. When the lights blink 4 times, turn the screw back clockwise all the way. This will reset the computer and erase the codes.

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