Subject: | DTC P0741 Sets After Extended Drive Time or During High Ambient Temps |
Models: | 2005-2007 Chevrolet Equinox |
| 2006-2007 Pontiac Torrent |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
DTC P0741 is set when:
- Torque Converter Clutch (TCC) is commanded "ON"
- Automatic Transmission Fluid (ATF) temperature is greater than 212°F (100°C)
- TCC slip speed is > 100 rpm for a cumulative time of +12 seconds during the current Key-Cycle
Recommendation/Instructions:
Engineering investigation shows that the root cause to this condition is due to a mechanical concern internal to the TCC assembly (Asm). This mechanical concern can cause residual ATF to become trapped between the front cover and the friction / clutch
apply plate internal to the TCC Asm thus not allowing the friction plate to fully engage / apply intermittently.
This intermittent condition is decreased as the ATF temperature increases below 212°F (100°C)
To help ensure that proper diagnosis and to verify / duplicate the DTC, perform the following road test
Procedure:
- Using a Tech II, review and record / capture the stored Freeze Frame Failure records
- If DTC P0741 set with an ATF temperature < 212°F (100°C), refer to SI document ID #157225
- If freeze frame records indicate that the DTC set with an ATF temperature = or > 212°F (100°C) continue to step #4
- Clear all prior DTCs and Freeze Frame Failure Records stored in the TCM & ECM
Note: It may be necessary to perform a Stall Test in order to increase the ATF to the required testing temperature. Refer to the Stall
Test procedure in SI.
- Monitor the ATF temperature until the actual temperature is at or > 212°F (100°C)
- With the ATF temperature at the testing specification, begin to road test the vehicle observing the following testing conditions:
• | Accelerate under normal driving conditions until the transmission current gear = 5 and the TCC command = "ON" |
| Note: Most cases highway conditions are most favorable to achieve testing conditions.
|
• | Release the throttle pedal for approximately 3 seconds |
• | Reapply the throttle pedal to achieve a throttle angle reading of 15% and hold this value for approximately 5 seconds |
• | Continue steps b & c above while ensuring that the ATF temperature stays > 212°F (100°C) during testing for approximately 5 minutes or until DTC P0741 resets |
| Note: In most cases, DTC P0741 will set within
1-2 minutes using the above testing procedure
|
- Once the DTC P0741 has been duplicated / verified, remove the transmission assembly to inspect the TCC inked ID / serial number on either the front or rear cover.
- Service stock of P/N 24227730 has been supplied of "known good" componets but inspection of the TCC ID markings is recommended to ensure the correct level of part arrived at the dealer before installing TCC in the vehicle.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.