Engine Controls - ECCS Limp Home Modifications
90nissan04Classification: Section:
EF&EC90-004 Emission Control
Reference: TECHNICAL BULLETIN NTB90-040
Models:
1990 Stanza, Axxess Date:
May 3, 1990
ECCS SYSTEM MODIFICATIONS
APPLIED MODELS: 1990 Stanza (U12) 1990 Axxess (M11)
SERVICE INFORMATION
1990 Stanza and Axxess vehicles include a "limp home" mode which allows the vehicle to be driven even if certain engine sensors are malfunctioning. Sensors in this system include the air flow meter, engine temperature sensor, air temperature sensor and throttle sensor. Engine speed is generally limited to 2,400 rpm when the system is activated.
This back-up system has been expanded to include the Vehicle Speed Sensor and Neutral Switch. System descriptions are outlined below:
Vehicle Speed Sensor
If the vehicle speed sensor malfunctions while driving under engine load, the E.C.U. will reduce engine speed to 2,000 rpm. After this occurs, engine speed will be limited to 2,500 rpm under all other driving conditions. The "limp home" condition is cancelled when the ignition switch is turned off.
Neutral Switch
When the neutral switch (M/T) or inhibitor switch (A/T) is shorted and vehicle speed exceeds 37 mph (60 km/h), the E.C.U. limits engine speed to 2,500 rpm. This "limp home" condition is cancelled when the ignition switch is turned off.
NOTE: Neither the E.C.U. or the Check Engine light indicate a neutral switch (M/T) or inhibitor switch malfunction during self-diagnosis.
Please note this Technical Bulletin on page EF&EC-27 in your copy of the 1990 Stanza Service Manual (June 1989 (01) printing) and the 1990 Axxess Service Manual (January 1989 (01) printing).