EXPERTEC TSB (91-259-6E)

Publication date: 1991-03-30
Reference number: 91-259-6E

EXPERTEC TSB

TECHNICAL SERVICE BULLETIN

Reference Number(s): 91-259-6E, Date of Issue: 03/30/91

REDUCED PERFORMANCE AND POWER - REPLACE ECM MODULE

Model(s): 1991 Chevrolet U Van With 3.1L Engine

Bulletin No.: Chevrolet 91-259-6E

Date: 03/30/1991

NOTE: THIS BULLETIN CANCELS AND SUPERSEDES DEALER SERVICE BULLETIN NO. 91-221-6E, DATED MARCH 1991. VIN BREAKPOINTS HAVE BEEN ADDED. ALL COPIES OF 91-221-6E SHOULD BE DISCARDED

CONDITION

Some owners of 1991 U-vans with 3.1L (VIN D) engine built prior to vehicle number MT1 23361 may comment about reduced performance and power.

CAUSE

The ECM (Electronic Control Module) may be incorrectly retarding the engine because of incorrect signal from ESC (Electronic Spark Control) module.

CORRECTION

If normal diagnostics as described in your shop manual (Section 6E2-B-3) do not correct this condition, replace ESC module with P/N 16126761 (Broadcast Code ANRZ).

PARTS INFORMATION

Parts are currently available from GMSPO.

WARRANTY INFORMATION

Use applicable Labor Operations And Times.