General Motors Chevrolet Tahoe 2009 User Manual

2011 Chevrolet Silverado - 4WD | Cheyenne, Sierra, Silverado VIN C/K Service Manual | Document ID: 2665095

#PI0106B: Malfunction Indicator Lamp (MIL) with DTC
P0741 or P0742 Set, Harsh 1-2 Shift - Diagnostic Aids ­(May 25, 2011)

Subject: Malfunction Indicator Lamp (MIL) with DTC P0741 or P0742 Set, Harsh

1-2 Shift – Diagnostic Aids

Models: 2009 Chevrolet Tahoe

Equipped with Police Package (RPO PPV)

2009-2011 Chevrolet Colorado, Express, Silverado, TrailBlazer

2009-2011 GMC Canyon, Envoy, Savana, Sierra

2009-2010 HUMMER H3, H3T

2009 Saab 9-7X

All Equipped with Automatic Transmission 4L60E (RPO M30) or 4L70E
(RPO M70)

This PI is being revised to add DTC P0742, update build dates and re-word step 1. Please
discard PI0106A.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern

Important: If the customer did not bring their vehicle in for this concern, DO NOT proceed with this

PI.

Some customers may comment that the malfunction indicator lamp (MIL) is illuminated and the
vehicle has a harsh 1-2 shift. Upon further investigation, technicians may find DTC P0741 or DTC
P0742 set as a current or history code in the transmission control module (TCM).

Recommendation/Instructions

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Note: For vehicles with low miles; Some vehicles were equipped with a single lock-tab connector

on the transmission. This includes Express and Savana models built prior to September
14, 2009 and Silverado and Sierra models built prior to July 1, 2011. This type of
connector may not be fully seated or may become dislodged. In this case DTC P0741 is
often accompanied by DTC P2764. Disconnect and reconnect the transmission wiring
harness to assure that it is properly seated and re-test the vehicle to confirm that the
code does not return.

1. DTC P0741 may be caused by debris in the transmission pump blocking the TCC apply valve or
the TCC apply valve orifice cup plug. DTC P0742 may be caused by debris blocking the TCC
apply valve.

Check for foreign material causing the TCC apply valve (1) to stick and not move fully. If
found, clear the debris and verify that the valve moves freely. If the foreign material is not
present in the valve, verify that the valve moves freely and is not sticking. If the valve is
sticking, replace the pump cover.

Inspect for foreign material blocking the orifice to the TCC apply valve (2). If material is
found in the cup plug, clear the material and reinstall the pump cover.

2. If the TCC apply valve has no issue, then look for other issues per diagnostic procedures for DTC
P0741 or P0742. Refer to DTC P0741 or P0742 – Automatic Transmission Diagnostic Information