Transmission code P0747

[Chevy366]

Man just got my TransGo kit installed and took the truck for a spin and got a orange engine light , went by Auotzone ran code and came up with P0747 , something about a high pressure solenoid valve stuck open .
I was very careful and made sure everything was clean and checked every move I made 3 times or more .
Truck shifts through all the gears except overdrive , has anyone else seen or heard of this happening ?

[RedHeartbeat]

Sounds like a solenoid didn't get hooked up correctly. I've never had any code like that before. P0757, yes, but that's to do with a huge stall.

[Bowtie70SS]

I did a shift kit install and got P0748...some dumbass(me) forgot to hook up the pressure solenoid. Also you need to torque the valve body bolts in a circle from inside towards the outside to keep from distorting it and binding something (per GM service manual).

Dave

[Chevy366]

I could not stand it , so I took the pan back off the trans ,(drain plug was a god send) , nothing all was well , that is all wires hooked up correctly , even went as far as to pull the valve body off again just to check the check balls , all were it right places , I think it is the tune doing it , to much line pressure .
Going to call TranGo and see what they say , I did notice that reverse hits real hard and I mean real hard , it jerks the truck when u put it in R , at low idle after engine warm up .

[Bowtie70SS]

That jerking is a sure sign of high line pressure. Mine did that with the pressure solenoid unhooked, now it's normal. If you had a previous tune with jacked line pressure you need to have the pressures returned to stock as the shift kit will raise the pressures for you.

Dave

[Chevy366]

<div class='quotetop'>QUOTE(Bowtie70SS &#064; Jun 12 2006, 05&#58;49 PM) [snapback]55290[/snapback]</div>

That jerking is a sure sign of high line pressure. Mine did that with the pressure solenoid unhooked, now it&#39;s normal. If you had a previous tune with jacked line pressure you need to have the pressures returned to stock as the shift kit will raise the pressures for you.

Dave
[/b]

That is what I thought , RedHeartBeat must have jinxed me , put it all back together and drove it again got a different code this time P0757 ( thanks Red ) , so what is the fix for the P0757 code ?
This time and last it seemed as if it did not go into overdrive , could hit the tow/haul button and would drop a gear but still not sure if overdrive is working right .

Thanks in advance .

[Bowtie70SS]

Here is the info out of the GM techline CD

DTC P0747
Circuit Description
Pressure control (PC) solenoid A is used to control oncoming, off-going, and holding pressure to any one of the five clutches. This solenoid is referred to as a pressure proportional to current (PPC) solenoid since the output hydraulic pressure supplied by this solenoid is proportional to the controlled current command.

The transmission control module (TCM) uses information from the turbine and output speed sensors to detect if a clutch is in a tie-up condition or 3 clutches are applied. The clutch being controlled by PC solenoid A will vary depending on the shift being made.

DTC P0747 is a type A DTC.

DTC Descriptor
This diagnostic procedure supports the following DTC:

DTC P0747 Pressure Solenoid A Stuck On

Conditions for Running the DTC
• DTCs P0716, P0717, P0721, P0722, P0875, and P0876 are not active.
• The components are powered and ignition voltage is greater than 9.0 volts and less than 18 volts.
• Output speed is greater than 200 RPM.
• Turbine speed is greater than 200 RPM.

Conditions for Setting the DTC
DTC P0747 sets if the TCM determines off-going clutch controlled by PC solenoid A remains engaged during a forward range shift.

Action Taken When the DTC Sets
• The TCM illuminates the malfunction indicator lamp (MIL).
• When failure occurs in a forward range, the transmission will go to the previous range. If failure occurs in NEUTRAL or REVERSE, the transmission will lock in NEUTRAL while diagnostic response is active.
• If the shift selector is moved to NEUTRAL, the transmission will shift to NEUTRAL.
• If the shift selector is moved to REVERSE, the transmission will shift to REVERSE or NEUTRAL, or in some cases may lock in NEUTRAL.
• If the shift selector is returned to a forward range and the transmission is compromised by over speeding or direction change, the transmission will shift to NEUTRAL.
• DTC P0747 will be stored in TCM history.
• The TCM freezes shift adapts.
• The TCM inhibits torque converter clutch (TCC) engagement.

Conditions for Clearing the DTC
A scan tool can clear the code from TCM history. The TCM automatically clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without failure.

Diagnostic Aids
• Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:
• A bent terminal
• A backed-out terminal
• A damaged terminal
• Poor terminal tension
• A chafed wire
• A broken wire inside the insulation
• When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.
• You may have to drive the vehicle in order to experience a condition.
• This DTC indicates the off-going clutch being controlled by PC solenoid A, is not releasing or is slow to release. This could indicate a leak or obstruction in a specific clutch apply circuit. Observe scan tool failure record data for previous or current range information when the DTC was set, to determine the specific shift when the DTC was set. Refer to Solenoid and Clutch Chart to determine which clutch circuit is suspect.
• Important: Clutch failure due to installation of an engine power upgrade is not covered under the manufacturers warranty.


Inspect for the presence of an add-on engine power package. When engine horsepower or torque is increased over factory rating, a shift flare condition may occur.

Test Description
The numbers below refer to the step numbers on the diagnostic table.

This step tests for proper ignition voltage.

This step tests for erratic speed sensor readings.

This step tests for internal hydraulic leakage.

This step tests for clutch capacity.

Step
Action
Value
Yes
No

Schematic Reference: Automatic Transmission Controls Schematics

1
Did you perform the Diagnostic System Check - Vehicle?
--
Go to Step 2
Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2
Measure the transmission fluid level. Refer to Transmission Fluid Checking Procedure .

Is the transmission fluid level correct?
--
Go to Step 3
Go to Transmission Fluid Checking Procedure

3
Install the scan tool.
Start the engine.
Important: Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function will erase the data.


Record the DTC Freeze Frame and Failure Records.
Clear the DTC.
Using the scan tool, measure ignition voltage.
Is the voltage within the specified range?
9-18 V
Go to Step 4
Go to DTC P0562 for low voltage or DTC P0563 for high voltage

4
Start the engine.
Drive the vehicle under normal operating conditions.
Using the scan tool, monitor engine, turbine, and output speed sensor readings.
Is speed sensor data erratic?
--
Go to the appropriate speed sensor DTC
Go to Step 5

5
Connect a 2,000 kPa (300 psi) pressure gage to the line pressure tap. Refer to Line Pressure Check Procedure .
Use the scan tool, in clutch test mode, to cycle through all transmission ranges with the engine at idle and vehicle brakes applied. Record line pressure in each range.
Was the line pressure low in a specific range or in ranges where the same clutch was applied?
--
Go to Low Main Line Pressure in All Ranges
Go to Step 6

6
Refer to Transmission Stall Test Notice in Cautions and Notices.

Conduct a clutch test for all forward ranges. Refer to Clutch Test .

Did turbine speed remain at zero in all ranges?
--
Go to Diagnostic Aids
Go to Step 7

7
Remove the transmission oil pan. Refer to Automatic Transmission Fluid/Filter Replacement .
Inspect for signs of clutch failure.
Are there signs of a clutch failure?
--
Go to Step 8
Go to Step 9

8
Remove the transmission for overhaul or replacement. Refer to Transmission Replacement .

Did you complete the repair or replacement?
--
Go to Step 11
--

9
Inspect for a stuck or sticking PC valve. Refer to Control Valve Body Cleaning and Inspection .

Did you find and repair a condition?
--
Go to Step 11
Go to Step 10

10
Replace PC solenoid A. Refer to Control Valve Solenoid Replacement .

Did you complete the replacement?
--
Go to Step 11
--

11
Perform the following procedure in order to verify the repair:

Clear the DTC.
Start the engine.
Use the scan tool to reset adaptive values for all shifts.
Operate the vehicle in all ranges under normal driving conditions.
Select Specific DTC.
Enter DTC P0747.
Has test run and passed?
System OK
Go to Step 1



--------------------------------------------------------------------------------
Document ID# 1492353
2005 Chevrolet Chevy C Silverado - 2WD


Dave

[Chevy366]

Wow , great info there , don&#39;t happen to have anything on DTC P0757 to ?
I think it has to do with solenoid B 2-3 shift stuck on ?
The truck ran fine at first today drove about 2 miles and slowed down to make a trun around and the light came on again .
I borrowed a code reader from a friend ( Thanks COWL327) and read the code P0757 , so bad solenoid or just trash in the valve or to much fluid pressure ?

Thanks

[Bowtie70SS]

DOH...I looked up the wrong code here you are...you have a 80e right?

Circuit Description
The 2-3 shift solenoid (SS) valve controls fluid flow acting on the 2-3 shift valves. The 2-3 SS valve is a normally open exhaust valve used with the 1-2 SS valve in order to allow for four different shift combinations.

If the powertrain control module (PCM) detects a non third gear ratio while third gear is commanded, then DTC P0757 sets. DTC P0757 is a type C DTC. For California emissions vehicles and vehicles under 8,600 GVW, DTC P0757 is a type A DTC.

DTC Descriptor
This diagnostic procedure supports the following DTC:

DTC P0757 2-3 Shift Solenoid (SS) Valve Performance - No Third or Fourth Gear

Conditions for Running the DTC
No MAF sensor DTC P0101, P0102 or P0103.
No MAP sensor DTC P0106, P0107, or P0108.
No TP sensor DTC P0120 or P0220.
No VSS DTC P0502 or P0503.
No ISS DTC P0716 or P0717.
No TCC Stuck On DTC P0742.
No shift solenoid electrical DTC P0753 or P0758.
No transmission component slipping DTC P0894.
No TFP manual valve position switch DTC P1810.
No TCC PWM electrical DTC P2761.
Transmission ISS is greater than 7 RPM.
The engine is running for greater than 7 seconds.
Not in 4WD low.
Transmission OSS is greater than 7 RPM.
The system voltage is 10-18 volts.
The throttle angle is greater than 10 percent.
The transmission fluid temperature (TFT) is greater than 20°C (68°F) and less than 130°C (266°F).
The engine torque must be 108-542 N·m (80-400 lb ft).
Conditions for Setting the DTC
The commanded gear equals 3rd and the ratio is 2nd for greater than 2.25 seconds.
All conditions are met for 7 occurrences.
Action Taken When the DTC Sets
The PCM illuminates the malfunction indicator lamp (MIL) for California emissions vehicles.
The PCM commands a soft landing to 2nd gear.
The PCM commands maximum line pressure.
The PCM freezes transmission adaptive functions.
The PCM inhibits 4th gear.
The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame, California only, and Failure Records, California and Federal.
The PCM stores DTC P0757 in PCM history.
Conditions for Clearing the MIL/DTC
For California emissions, the PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
A scan tool can clear the MIL/DTC.
For California emissions, the PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission related diagnostic fault occurring.
For Federal emissions, the PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring.
The PCM cancels the DTC default actions when the fault no longer exists and the ignition switch is OFF long enough in order to power down the PCM.
Diagnostic Aids
Verify that the transmission meets the specifications in the Shift Speed table. Refer to Shift Speed .
Other internal transmission failures may cause incorrect gear ratios to occur in 3rd gear.
The customer may have concern of an engine over-rev condition or neutral condition in 4th gear. Refer to Shift Solenoid Valve State and Gear Ratio .
DTC P0757 defaults to an elevated line pressure condition which may result in partial TCC apply. This may produce an idle surge that could stall the engine.
Test Description
The number below refers to the step number on the diagnostic table.

This step tests that the PCM commanded all shifts, that all shift solenoid valves responded correctly, but that all the shifts did not occur.

Step
Action
Value(s)
Yes
No

1
Did you perform the Diagnostic System Check - Vehicle?
--
Go to Step 2
Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2
Install a scan tool.
Turn ON the ignition, with the engine OFF.

Important
Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the PCM.


Record the DTC Freeze Frame and Failure Records.
Clear the DTC.
Drive the vehicle in D4 range, accelerating the vehicle, ensuring that the PCM commands 1st, 2nd 3rd and 4th gears.
Did you detect a 1-2-2-1 shift pattern?
--
Go to Step 3
Go to Intermittent Conditions in Engine Controls - 6.0L

3
Inspect the shift solenoid/hydraulic circuit for the following conditions:
2-3 shift solenoid mechanically stuck OFF Refer to Shift Solenoid Leak Test .
2-3 shift valve stuck in the released position
Damaged seals on the shift solenoid valves Refer to Shift Solenoid Leak Test .
Clean and inspect the related valves, bores and the valve body for debris or contamination restricting valve movement. Refer to Control Valve Body Cleaning and Inspection in Transmission Unit Repair Manual.
Did you find and correct the condition?
--
Go to Step 4
--

4
Perform the following procedure in order to verify the repair:

Select DTC.
Select Clear Info.
Drive the vehicle in D4 range, holding the throttle at 40% and accelerating to 89 km/h (55 mph), only if traffic and road conditions permit.
Select Specific DTC.
Enter DTC P0757.
Has the test run and passed?
--
Go to Step 5
Go to Step 2

5
With the scan tool, observe the stored information, capture info and DTC info.

Does the scan tool display any DTCs that you have not diagnosed?
--
Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information
System OK



--------------------------------------------------------------------------------
Document ID# 1395551
2005 Chevrolet Chevy C Silverado - 2WD


Sorry if I would have read it right the first time it wouldn&#39;t have taken so long.

Dave

[Chevy366]

Again ,Wow , some great reading , that stuff you have there is handy to have around &#33;
The kit directions had me drill two holes in the valve body at the solenoid A and B plunger locations , so my guess would be that either I left some debris there or the holes have burrs on them and are causing the valve to stick , I read somewhere that most P07xx codes are mechanical in nature and not electrical .

Thanks agian &#33;
Knowledge , got to love it .