DTC 39

Code 39 Chart:

Code 39 Wiring Diagram:

CIRCUIT DESCRIPTION:

The ECM controls TCC operation by grounding CKT 422 through the quad-driver.

Code 39 will set when:

^ No Code 29 is present.

^ Brake switch is closed, "OFF". (Brake is not applied).

^ TCC is commanded "ON" by the ECM.

^ Vehicle is in 4th gear.

^ he engine speed to vehicle speed ratio is outside of its window of operation.

^ All of the above for a time greater than 30 seconds.

NOTE: Because of all the possible color code combinations used on electrical wiring diagrams, always refer to ECM CONNECTOR IDENTIFICATION under ELECTRICAL AND ELECTRONIC WIRING DIAGRAMS for correct color code identification of circuit.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. Checks fuse, brake switch and B+ circuit to the TCC solenoid.

2. Checks availability of B+ on CKT 420.

3. Electrical circuits have checked out. If there is a TCC engagement problem, it is a transmission problem.


DIAGNOSTIC AIDS:


^ A Code 39 in combination with a Code 38 would mean a problem with one or more of the following components. Fuse, CKT 639, brake switch or wire before the splice. A single Code 39 is the result of a wire or CKT 420 problem between the splice and the TCC solenoid, CKT 422 problem between TCC solenoid and ECM, poor connection to ECM connector, or possibly the ECM.