Electronic Concentrated Engine Control System (ECCS) (TS86-109)
Publication date: 1986-06-18Reference number: TS86-109
ELECTRONIC CONCENTRATED ENGINE CONTROL SYSTEM (ECCS)
TECHNICAL SERVICE BULLETIN
ECCS CHECKER BOX, 1987 NISSAN MODELS
Model(s): 1987 Nissan Models
Section: Engine Fuel
Classification: EF86-007
Bulletin No.: TS86-109
Date: June 18, 1986
APPLIED MODELS
All 1987 and later Nissan Models except some early production 1987 Sentra Coupe (B12) vehicles
INTRODUCTION
The ECCS Checker Box may be used to control and read the self-diagnosis systems on most 1987 and later Nissan vehicles equipped with ECCS (Electronic Concentrated Engine Control System). It is an easy tool to use - simply plug it into the "check connector" located under the left side of the dash or at the use block, start the engine and allow it to warm up to operating temperature, then use the Checker Box switch to trigger each of the self-diagnosis "modes." You can read the Red and Green light-emitting diode (L.E.D.) codes in the Checker Box, so it is not necessary to remove the vehicle control unit. The Checker Box also has an audible tone for each L.E.D. signal, so you can "hear" the codes during a road test if you wish - and keep you eyes on the road.
There are five "modes" of self-diagnosis built into all Nissan models that can use the ECCS Checker Box. The ECCS Checker Box will use an electronic signal from its switch to trigger each "mode," and it will indicate the "mode" you're in with a numerical read-out.
SUMMARY OF THE FIVE "MODES" OF ECCS SELF-DIAGNOSIS
MODE 1
In this mode, the control unit monitors the mixture ratio feedback signal from the exhaust gas sensor. Assuming the engine is warmed up and in "closed-loop" operation, a flashing Green L.E.D. indicates that the control unit is receiving a mixture ratio signal from the exhaust gas sensor and that the control unit is responding.
MODE 2
In this mode, the Red and Green L.E.D.s flash to indicate the mixture ratio. If the L.E.D.'s flash simultaneously, or very nearly simultaneously, they indicate that the engine air-fuel mixture is in the correct range or best efficiency of the 3-way converter.
MODE 3
In this mode, the self-diagnosis system recalls any gross electrical malfunction (extremely low current draw, or extremely high current draw) that has occurred in the ECCS system and displays a code to indicate the circuit in which it appeared.
MODE 4
This mode checks the function of specific on-off switch circuits that serve as inputs to the ECCS system, such as the "Start" signal of the ignition switch, the idle speed and the vehicle speed sensor.
MODE 5
This mode is called "real-time" diagnosis. It checks several of the most important ECCS sensor circuits, such as the crank angle sensor and the air flow meter, at very high sensitivity.
REPAIR PROCEDURE FOR USING THE ECCS CHECKER BOX
The following gives a general procedure for using the ECCS Checker Box to set the self-diagnosis modes in operation and to read the L.E.D. codes. Once the Box is plugged into the test connector on the vehicle, it can change the modes quickly from one to the other, so it will be simple to check all parts of the ECCS system at one sitting.