A/T - Second Gear Switch, ECM Connector, DTC Code 62

89pontiac26

Bulletin Number: 90-6-7A
Reference Number: 916525R
Publish Date: 12/89

Subject: SERVICE MANUAL UPDATE-SECTION 6E3- DRIVEABILITY AND EMISSIONS REVISED CODE 62 FACING PAGE AND CHART

Models

Affected: 1990 GRAND AM 2.3L (VIN D)

This bulletin has been revised to include proper location of second gear switch, labeling of ECM connector and to clarify Code 62 chart. (Revised art attached).

This bulletin serves to update the Code 62 chart and facing page in Section 6E3 "Driveability And Emissions" in the 1990 Service Manuals with 2.3L Grand Am (VIN D) applications. (Chart and facing page attached)






CODE 62

TRANSAXLE GEAR SWITCHES CIRCUIT 2.3L (VIN D) "N" CARLINE (PORT)

Circuit Description:
Code 62 diagnostic is used to check the 2nd and 3rd gear switch inputs to the ECM. Transmission gear input signals to the ECM are determined as follows:
1st gear = 2nd gear switch closed
(also P/N & R) 3rd gear switch closed
2nd gear = 2nd gear switch open
3rd gear switch closed
3rd gear = 2nd gear switch open
3rd gear switch open
Test Description: Numbers below refer to circled numbers on the diagnostic chart. Code 62 will set if any of the following conditions are met for approximately 17 seconds:
^ In "PARK" or "NEUTRAL" and 2nd or 3rd gear indicated.
^ Vehicle speed less than approximately 5 mph and 2nd or 3rd gear indicated.
^ First or second gear indicated, less than approx. 3000 rpm, not in P/N, and VSS greater than 50 mph.
^ Vehicle at operating temperature.
1. Step one checks for an open or grounded circuit between transmission connector and ECM. Since the ECM terminals are normally high, B+ should indicated at both terminals with the connector removed.
2. The DVM should measure near B+ because the 2nd and 3rd gear switches should provide continuity to ground.
3. The third step checks to see if the transmission switches function normally. In third gear both switches should have changed from their original 1st gear state.

Diagnostic Aids:

Clear codes and recheck for Code 62. If code resets, check all harness connections, VSS, rpm, P/N circuits prior to replacing an ECM. Transmission starting in 2nd or 3rd gear or a sticky 2nd gear switch can also cause Code 62. Refer to Section "7" for transaxle diagnosis information.