A/T - LA4AEL MIL ON/Harsh Shifts/DTC P0741 Set
Bulletin No.: 002/97Issued: 03/10/97
Revised
Category
K
Applicable Model/s
1996-97
626/MX-6 (2.0L A/T)
Subject:
DIAGNOSTIC TROUBLE CODE P0741 TORQUE CONV. CLUTCH SYS. PERFORMANCE
APPLICABLE MODELS
1996 - 97 626/ MX-6 equipped with a LA4A-EL transaxle and a 2.0L engine.
DESCRIPTION
Diagnostic Trouble Code (DTC) P0741 (possibly accompanied by a flashing O/D light, MIL light and harsh shifts/shift engagement) may be due to a reduction in hydraulic pressure within the torque converter clutch circuit. As pressure falls below the torque convener lock-up specifications, torque converter slippage occurs. Customers complaining of the above symptoms should have the vehicle inspected and if necessary, repaired according to the instructions provided with this bulletin.
Service Managers are asked to place the instructions into section K2 of the appropriate workshop manual. Two (2) sets of instructions are provided to cover both applicable manuals (1996 and 1997).
PARTS INFORMATION
SPECIAL TOOLS REQUIRED
WARRANTY INFORMATION
(Applies To Verified Customer Complaints On Vehicles Covered Under Normal Warranty Refer To The SRT Microfiche For Warranty Term Information.)
Warranty Type: A
Symptom Code: 28
Damage Code: 91
Part Number Main Cause: See Parts Information
Quantity: As Needed
REPAIR PROCEDURE - DTC P0741
1. Verify the concern.
2. Connect the NGS tester (SST 49 T088 0A0).
3. Retrieve and record all DTCs including freeze frame data.
4. Clear all DTCs.
5. Diagnose and repair all conditions other than TCC (Torque Converter Clutch) system performance (DTC P0741) or transaxle over temperature (DTC P1783).
NOTE:
Pay special attention to any TSS (Turbine Speed Sensor) or VSS (Vehicle Speed Sensor) related DTCs.
6. Monitor the following PIDs (Parameter Identification Data) with the NGS tester in PID/Data monitor and record mode:
^ TSS
^ Engine RPM
7. Connect the transmission tester (SST 49 UN01 071) with the LA4A-EL cable and overlay (SST 49 UN01 089 and 49 UN01 090)
8. Place the transmission tester in bench mode.
NOTE:
Vehicle must be parked for bench mode testing.
Do not attach the TSS lead of the transmission tester cable to the transaxle for any of these test procedures.
9. Press the TCC activate button.
^ If the status light turns green, proceed to step 10.
^ If the status light does not turn green, recheck all connections and retest If the light still does not turn green, replace the solenoid body and repeat test.
10. Check the TCC solenoid resistance values with the transmission tester TCC and VPWR test pins.
NOTE:
The TCC solenoid should be a high impedance type for 1996 model year and later. Verify the type of TCC solenoid on the vehicle by looking at the solenoid body bulkhead connector. A BLACK solenoid bulkhead body is incorrect and must be replaced with a high impedance type (natural/beige).
High Impedance (12.5 - 19.0 ohms) Natural / Beige Color Bulkhead Connector (1996 model year and later)
Low Impedance (1.0 - 2.0 ohms) Black Color Bulkhead Connector
^ If the TCC solenoid resistance is within specification, proceed to step 11.
^ If the TCC solenoid resistance is not within specification, or is a low impedance type, replace the solenoid body and test again.
11. Switch the transmission tester into drive mode and prepare for a test drive.
NOTE:
A test drive will require an assistant to operate the transmission tester and monitor the NGS tester.
12. Place the vehicle shift lever in O/D position.
^ Do not cycle the "O/D Off" switch during this procedure.
^ Use the transmission tester to manually upshift the vehicle into 4th gear after reaching 45mph.
13. While observing the engine rpm on the NGS tester, press and hold the TCC button on the transmission tester to engage TCC solenoid.
^ If the rpm decreases slightly, proceed to step 14.
^ If rpm does not decrease, check the TCC status light on the transmission tester.
a) If the light is green, proceed to step 14.
b) If the light did not turn green, check the connectors and recheck. If light is still not green, refer to step 9.
14. Press and hold the TCC button while maintaining 45mph and 4th gear. After 5 seconds, observe engine rpm and TSS rpm. Accelerate lightly and record engine rpm and TSS rpm.
^ If the engine rpm and TSS rpm remain within 50 rpm of each other, proceed to step 17.
^ If the engine rpm and TSS rpm do not remain within 50 rpm of each other, proceed to step 15.
15. Accelerate to 65 mph in 4th gear (local Speed limits apply).
16. Press and hold the TCC button. After 5 seconds observe the engine rpm and TSS rpm. Accelerate lightly and record engine rpm and TSS rpm.
^ If the engine rpm and TSS rpm remain within 50 rpm of each other, replace the transaxle, do not attempt repair.
^ If the engine rpm and TSS rpm do not remain within 50 rpm of each other, replace the torque converter.
17. Downshift the vehicle into 3rd gear using the transmission tester while maintaining 45mph.
18. Press and hold the TCC button. After 5 seconds, observe engine rpm and TSS rpm. Accelerate lightly and record engine rpm and TSS rpm.
^ If the engine rpm and TSS rpm remain within 50 rpm of each other, proceed to step 19.
^ If the engine rpm and TSS rpm do not remain within 50 rpm of each other, replace the torque converter.
19. Press and hold the TCC button while maintaining 45mph and 3rd gear. After 5 seconds, observe engine rpm and TSS rpm. Accelerate lightly and place a small load on the engine (engage parking brake just enough to reduce vehicle speed). Record engine rpm and TSS rpm.
^ If the engine rpm and TSS rpm remain within 50 rpm of each other, there are no hydraulic concerns present with the TCC system.
^ If the engine rpm and TSS rpm do not remain within 50 rpm of each other, replace the torque converter.
CAUTION:
If transaxle replacement is necessary, flush oil cooler to remove any accumulated friction material. Failure to properly flush the oil cooler may result in a premature failure of the remanufactured transmission.
DISCLAIMER