A/T - Driveability Concerns/DTC's Set/MIL ON
Group: TRANSAXLENumber: 97-40-025-1
Date: August, 1997
Model: ALL
Subject:
PULSE GENERATOR DIAGNOSIS
This TSB revises TSB # 97-40-025 to provide additional diagnosis procedures.
DESCRIPTION:
The following conditions may be caused by an improperly functioning pulse generator. The conditions may be intermittent and difficult to duplicate.
^ 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
^ Erratic downshift during light acceleration
^ Third-gear "fail-safe" condition and/or "Check Engine" light on
^ Bucking and/or hesitation
The following DTC may be stored in memory in the transaxle control module (TCM):
OBD II NON-OBD II DESCRIPTION
P0717 31 and/or 81* No pulse generator-A signal
P0722 32 and/or 82* No pulse generator-B signal
Note 1:
*Fail-safe code
Note 2:
Always check the "Transaxle" menu in the HDS scanner for additional codes. DTC P0732 (non-synchronous 2nd Gear), P0733 (nonsynchronous 3rd Gear), P0734 (non-synchronous 4th Gear) and P1624 (transaxle system concern) may also be found in memory in the TCM. These DTCs may be induced by the incorrect output of the PG-B and do not necessarily indicate a mechanical condition in the transaxle. After repairs are made to the pulse generator, clear the codes and test drive the vehicle for two driving cycles. If the DTCs do not return, the codes were induced by the incorrect output of the PG-B.
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", and "Codes". If DTC for pulse generators shown on the previous page are stored in memory, replace the pulse generators and 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 approximately 30 mph in third gear, with the overdrive switch off, have an assistant monitor PG-A and PG-B. Check that both PG-A and PG-B are approximately equal to the engine rpm in third gear.
^ If so, continue to "Main Connector Repair".
^ If not or if the PG-A or PG-B outputs fluctuate rapidly when the improper shift condition occurs, the pulse generators are not functioning properly or the wiring harness is damaged. Continue to "Main Connector Repair".
SERVICE PROCEDURE:
A) Main Connector Repair:
1. Disconnect the pulse generator main connector from the engine harness.
2. 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.
3. Clean both ends of the pulse generator connector with aerosol electrical contact cleaner.
4. Reconnect the main connector.
B) Test Procedure:
1. Disconnect the pulse generator main connector from the engine harness.
2. 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 ohms, replace the pulse generator.
3. If the resistance is within specification, reconnect the pulse generator main connector and use an ohmmeter or HDS sweep test to check the continuity of the engine harness between the TCM and the pulse generator. The resistance should be 215-275 ohms.
4. If the resistance is not 215-275 ohms, 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 (check that there is no tension in the wires when the engine is under load in Drive). Refer to the electrical section of the appropriate Shop Manual and check the ground for the shielded wiring.
5. Repair or replace the harness if necessary.
WARRANTY INFORMATION:
Normal warranty operation codes and times apply.