How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask GMC Tech Your Own Question
GMC Tech
GMC Tech, GMC Technician
Category: GM
Satisfied Customers: 390
Experience:  Pa state emissions cert. GM training in all areas. 5 years as a technician top of graduating class.
14353791
Type Your GM Question Here...
GMC Tech is online now
A new question is answered every 9 seconds

GMC 2500hd hi i have a 2007 gmc 2500hd 6.0L and an engine

Customer Question

hi i have a 2007 gmc 2500hd 6.0L and an engine code po894 transmission slipping came up it has 107k miles on it si i thought trani oil and filter needs changed so i did that and the code came back again. whats goin on here?
Submitted: 5 years ago.
Category: GM
Expert:  GMC Tech replied 5 years ago.

Hello GM has a document on your issue for the code P0894 about the transmission slipping.The torque converter clutch enable solenoid has been found to be cracked down the side of it and has to be replaced along with the wire harness. I'll post the document below.

 

 


#06-07-30-007A: Malfunction Indicator Lamp (MIL) On, Diagnostic Trouble Code (DTC) P0894, Harsh 1-2 Shift with 4L60-E, 4L65-E, 4L70-E Auto Transmission (Test/Replace TCC Enable Solenoid/Harness, Auto Trans Wiring) - (Feb 20, 2007)

 

Subject:Malfunction Indicator Lamp (MIL) On, Diagnostic Trouble Code (DTC) P0894, Harsh 1-2 Shift with 4L60-E, 4L65-E, 4L70-E Automatic Transmission (Test and Replace Torque Converter Clutch (TCC) Enable Solenoid / Harness, Auto Trans Wiring)

 

Models:2006 Cadillac Escalade Models
2006 Chevrolet Light Duty Trucks
2006 Chevrolet Express Vans
2006 GMC Light Duty Trucks
2006 GMC Savana Vans
2006 Pontiac GTO
2006 HUMMER H2, H3
2006 Saab 9-7X
with 4L60-E / 4L65-E / 4L70-E (RPOs M30, M32, M70) Automatic Transmission

 


This bulletin is being revised to add part number for vehicles with Input Speed Sensor (ISS). Please discard Corporate Bulletin Number 06-07-30-007 (Section 07 -- Transmission/Transaxle

 

 

Condition

Some customers may comment on a harsh 1-2 shift with the MIL illuminated.

Diagnosis with a scan tool may reveal a DTC P0894.

Cause

 

 

 

This condition may be caused by a leaking TCC enable solenoid. The TCC enable solenoid is part of the automatic transmission wiring harness.

Correction

 

Follow the diagnosis and repair procedure below for a DTC P0894.

  1. With a scan tool, verify the presence of DTC P0894.
  2. Remove the TCC Enable solenoid / automatic transmission wiring harness. Refer to Torque Converter Clutch Pulse Width Modulation (TCC PWM) Solenoid, TCC Solenoid, and Wiring Harness in the appropriate SI Document.

 

 

graphic

 

 

 

Typically if the TCC enable solenoid is found to have a crack / fracture (2), it will be located parallel to the mold seam (1) as shown above.
Engineering investigation shows that TCC enable solenoids that are brown in color may exhibit the cracking / fracture condition.
Engineering investigation shows that TCC enable solenoids that are off-white in color do not exhibit the cracking / fracture condition.

  • Air check the TCC enable solenoid using solenoid testing kit.
  • graphic

     

     

     

  • Install the TCC enable solenoid into bore #2 of J 44246 as shown above.
  • While air is being applied to the solenoid through J 44246, coat the outside of the solenoid body with transmission fluid to help expose a possible vertical crack in the molded part of the solenoid body. This crack may be very small and not visible without the use of ATF. Complete instructions for the Shift Solenoid Leak Test can be found in SI Document ID # XXXXX
    If NO visual leaks are found in the TCC enable solenoid, refer to DTC P0894 in the appropriate SI Document.
    If visual leaks are found in the TCC enable solenoid, continue with the next step.
  • Replace the TCC enable solenoid. Refer to Torque Converter Clutch Pulse Width Modulation (TCC PWM) Solenoid, TCC Solenoid, and Wiring Harness in the appropriate SI Document.
  • Road test the vehicle.
  •  

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

    PLEASE HIT THE ACCEPT BUTTON OTHERWISE I DO NOT RECEIVE CREDIT FOR THE ANSWER GIVEN. INFORMATION GIVEN FOR EDUCATIONAL PURPOSES ONLY.

    Customer: replied 5 years ago.
    what about a possible fautly tps sensor. i was told sometimes they read more throttle than normal at idle and thus tell the transmission to shift harder when it does not need too?
    Expert:  GMC Tech replied 5 years ago.
    Do you have an Allison transmission?
    Customer: replied 5 years ago.
    no i do not. i have a 6.0L
    Expert:  GMC Tech replied 5 years ago.

    Your truck uses a throttle actuator control which is incorporated into one and it eliminated a separate throttle position sensor. The P0894 is a specific code internally to the transmission.

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

    IF THIS HAS HELPED YOU OUT PLEASE HIT THE ACCEPT BUTTON OTHERWISE I DO NOT RECEIVE CREDIT. THANK YOU.

    GMC Tech and 3 other GM Specialists are ready to help you
    Customer: replied 5 years ago.
    i understand theres some kits out there that if the body is cracked you can bore out the valve body and replace an insert ot larger solenoid.. do you reccomend this if this is the case. im not sure about that procedure... also could a screen in the tcc maybe plugged?
    Expert:  GMC Tech replied 5 years ago.
    I don't recommend doing any boring i would definitely do a fine tooth comb visual examination. Yes the screen could be plugged i have seen that before.
    Customer: replied 5 years ago.

    ok thanks so much sir... youve been a big help

     

    Expert:  GMC Tech replied 5 years ago.
    No problem. Thank you!