A/T - Delayed/Harsh/Erratic Upshifts/Downshifts

Group
40 - TRANSAXLE

Number
96-40-013

Date
07-1996

Model
Accent 1995-1996, Elantra 1992-1996, Excel 1986-1994, Scoupe 1991-1995 and Sonata 1989-1996

Subject
PULSE GENERATOR DIAGNOSIS

DESCRIPTION:

The following conditions may be caused by an improperly functioning pulse generator.

The conditions may be intermittent and difficult to duplicate. A code may or may not be stored in the Transmission Control Module (TCM).

^ Delayed or erratic 1-2 shift, with engine hot or cold.

^ Harsh 1-2 shift.

^ Harsh 2-1 downshift, at a higher speed than the normally scheduled downshift.

^ Third-gear "fail-safe" condition.

DIAGNOSTIC PROCEDURE:

As part of the diagnostic procedure, inspect and test the pulse generator according to the procedure shown below:

1. Turn the ignition switch to "ON" and connect the HDS Scanner to the Data Link Connector (DLC).

2. From the Menu, select "Transaxle," "Codes and Data Menu," and "Codes." If fault codes for Pulse Generator-A (PG-A) or Pulse Generator-B (PG-B) are stored, go to the" Main Connector Repair" section of this TSB. If no codes are stored, continue to step 3.

3. From the Menu, select "Data". While driving the vehicle at 30 mph in third gear, with the overdrive switch off have an assistant monitor PG-A and PG-B. Both PG-A and PG-B should be approximately equal to the engine rpm at 30 mph in third gear.

4. If the PG-A or PG-B readouts are not approximately equal to engine rpm in third gear or fluctuate rapidly when the improper shift condition occurs, the pulse generators are not functioning properly or the wiring harness is damaged.

SERVICE PROCEDURE:

A) MAIN CONNECTOR REPAIR:

5. Disconnect the pulse generator main connector from the engine harness.





6. Using small needle nose pliers, gently twist the male pins in the pulse generator main connector approximately ten (10) degrees clockwise to ensure electrical contact.





7. Reconnect the main connector.

B) TEST PROCEDURE:

8. Disconnect the pulse generator main connector from the engine harness.





9. Use an ohmmeter to check the resistance between the male terminals 1-2 and 3-4 as shown. If the resistance is not within the specification of 215-275 Ohm), replace the pulse generator.

10. If the resistance is within specification, use an ohmmeter or HDS sweep test to check the continuity of the engine harness between the TCM and the pulse generator main connector.

11. Carefully check the harness near the engine mounts for damage to the wiring that may cause open or short circuits. Reposition any wires that put tension on the PG connector; there must be slack in the PG wiring assembly. Refer to the Electrical section of the appropriate shop manual and check the ground for the shielded wiring.

12. Repair or replace the harness if necessary.