DTC 62

Code 62 Chart:

Code 62 Wiring Diagram:

***UPDATED BY TSB 90-T-16 DATED OCTOBER 1989

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 be indicated at both terminals with the connector removed.


2. The DVM should measure near 12 volts volts to because the 2nd and 3rd gear switch 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.