I/M Emissions Diagnostic Manual -Program
NO.: 51-65-02DATE: February, 1995
SECTION: 6E - Engine Fuel & Emission
MODELS:
1995 and Prior Passenger Cars and Trucks
SUBJECT:
Inspection/Maintenance (I/M) Emissions Diagnostic Manual - Manual Number G MI95-IM24O-2
GENERAL INFORMATION
The Enhanced Inspection/Maintenance (I/M) program is scheduled to begin in designated areas of the country in January 1995. Refer to GM Service Bulletin 43-65-07, dated December 1994, for a list of states participating in this new emissions testing program. Also refer to GM Service Bulletin 43-65-05, dated April 1994, for information on this emissions testing program and a description of the I/M 240 loaded mode test.
INSPECTION/MAINTENANCE (I/M) EMISSIONS
DIAGNOSTICS
Copies of the Inspection/Maintenance (I/M) Emissions Diagnostic manual will be shipped to all dealerships regardless of whether your state is participating in the enhanced I/M testing program. For dealerships in areas performing I/M testing, the subject manual provides a strategy based diagnostic approach to repairing I/M test failures. For dealerships in areas not affected by enhanced I/M testing, the new diagnostic procedures provided in this manual may be helpful for diagnosing the oxygen sensor, oxidation and three way catalytic converter, and EVAP system.
The Inspection/Maintenance (I/M) Emissions Diagnostic Manual provides complete emissions diagnostic procedures for all fuel system types (both open and closed loop carburetor, TBI, and MFI). The manual also provides evaporative (EVAP) emissions system diagnostics for EVAP pressure and EVAP purge flow. The emissions diagnostic procedures outlined in the Inspection/Maintenance (I/M) Emissions Diagnostic Manual follow the strategy based diagnostic approach and include the following new tests developed specifically for the I/M program.
OXYGEN SENSOR (02S) TEST
There are two versions of the O2S test procedure for use with the Tech 1 scan tool; an automated test using the Tech 1 and Mass Storage Cartridge (MSC), and a manual procedure using the Tech 1's snapshot function. The MSC version of the 02S test is scheduled for release in early 1995.
OXIDATION AND THREE WAY CATALYTIC CONVERTER TEST
Patent Pending Us Patent Office, Serial No. 236837
This test can be used to diagnose excessive emission failures resulting from damaged/poisoned or tampered oxidation and three way catalytic converters. Procedures for both single and dual converter systems are included. This test requires the use of the Propane Enrichment Device (J 26911 or J 41417) and an exhaust gas analyzer meeting the specifications outlined in GM Service Bulletin 43-65-07, dated December 1994.
EVAP PRESSURE TEST
The EVAP pressure test is used to diagnose and locate leaks in the fuel tank and EVAP system. This test requires the use of the EVAP System Diagnostic Kit (J 41600).
EVAP PURGE FLOW TEST
The EVAP purge flow test is used to diagnose the loss of EVAP purge flow. Detailed procedures for all EVAP system configurations are provided. This test requires the use of the EVAP Pressure/Purge Diagnostic Station (J 41413) and the Purge Flow Indicator (J 41418) supplied as part of the EVAP System Diagnostic kit (J 41600).
TECHNICAL ASSISTANCE FOR ENHANCED I/M (I/M 240) FAILURES
Dealer technicians are granted access to all divisional technical assistance staffs when repairing I/M 240 emissions test failures. Refer to GM Service Bulletin 43-65-06, dated October 1994 for complete details.
BASIC/ENHANCED I/M EMISSIONS DIAGNOSIS TRAINING
GM has developed the following emissions training program specifically for dealers located in enhanced I/M testing areas: VEHICLE EMISSIONS,
ENHANCED TESTING AND DIAGNOSIS (Course # 16004.10). Contact your local GM training center for class schedules, enrollment information, and prerequisites.
Additional copies of the Inspection/Maintenance Emissions Diagnostic Manual (GM/95-IM240-2) may be obtained from Helm Inc. 1-800-782-4356.