Emissions - Maintenance Light Stays ON
Article No. 85-21-11LIGHT - EMISSION - STAYS ON
LIGHT TRUCK 1985 ALL LIGHT TRUCKS
The emission maintenance warning system functions with two microprocessor modules. One module is the inferred mileage sensor (IMS) and the other is the emission maintenance warning (EMW) module. The IMS module is not part of the emission light circuit. The IMS module sends a signal to the engine control assembly (ECA) at a predetermined time which then automatically makes appropriate internal emission control adjustments.
The EMW module is a timing device that turns the "EMISSIONS" light on at approximately 60,000 miles, indicating required emission system maintenance. 1985 light trucks built prior to January 1985 have a non-resetable EMW module and require part replacement if the "EMISSIONS" light stays on. Later vehicles are equipped with a resetable EMW module and can be reset as described in the 1985 Car/LightTruck EngineElectrical-Emissions Shop Manual, page 18-6.
An additional EMW module is available and is used only for vehicles with approximately 30,000 miles. This module will ensure that the "EMISSIONS" light will still be illuminated as required at 60,000 miles. Locations for the EMW/IMS modules are as follows:
Model Location
F Series Left side of steering column on instru-
Econoline ment panel support.
Bronco
Aerostar Left side of steering column mounted
on the EEC-IV processor bracket.
Ranger Behind and above the glove box.
Bronco II Mounted on the instrument panel.
(May require glove box removal.)
The IMS and EMW modules are located side by side. The EMW module is the only part that normally requires replacement. It can be identified by a "RESET" sticker and brown plastic housing. The IMS module is black in color and has no stickers.
Figure 13 - Module Flange:
Installation Note
E/F Series and Bronco access is limited. Installing a new module may require slotting of the upper mounting hole on the module flange (see Figure 13). This allows starting of the upper screw in the instrument panel support so the module can then be slid under the screw head before tightening.
PART NUMBER PART NAME CLASS
E5TZ-12B514-A EMW Module - 60K C
Resetable
E5TZ-12B514-C EMW Module - 30K C
Resetable
E1TZ-12B514-A IMS Module - No C
Adjustments
OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: Reimbursable within the provisions of the Warranty and Policy Manual.
OPERATION: SP12514A85
TIME: 0.3 Hr. - Ranger and Bronco II 0.4 Hr. - Aerostar 0.5 Hr. - F Series, Bronco, Econoline DLR. CODING: Basic Part No. 12B514 - Code: 42