the code that i am getting is p1621 my pred says customer snap shot requested. i checked the dtc list on here and it said control module long term memory performance. i have no idea what this means. i can clear the code and it will come back but not inder normal driving. i have to get into the peddle pretty good and then the truck does this stutter thing during acceleration. let off and get back on it and its fine. check the pred and this code is there. it has done this before i got the pred so i know its not the programmer, but it is more frequent now. anybody got a clue

Subject: Powertrain Control Module (PCM), Engine Control Module (ECM), Transmission Control Module (ECM), Transmission Control Module (TCM) DTCs P0601/P0602/P0603/P0604,/P1621 Shared in Multiple Modules #05-06-04-060 - (09/23/2005)



Models: 2005-2006 GM Passenger Cars and Light Duty Trucks (including Saturn)

2005-2006 HUMMER H2

2006 HUMMER H3

2005-2006 Saab 9-7X




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Beginning in 2005, some control modules (ECM's, TCM's) have specific codes that describe internal failures of the module. These DTCs are not module specific and can be found on any controller that has these codes.

Society of Automotive Engineers (SAE) J2012 committee has set these specific codes to be an industry standard of all manufacturers.

Currently, these common codes are:

• P0601 -- Control Module Read Only Memory (ROM)

• P0601 -- Transmission Control Module (TCM) Read Only Memory (ROM)

• P0602 -- Control Module Not Programmed

• P0602 -- Transmission Control Module (TCM) Not Programmed

• P0603 -- Control Module Long Term Memory Reset

• P0603 -- Transmission Control Module (TCM) Long Term Memory Reset

• P0604 -- Control Module Random Access Memory (RAM)

• P0604 -- Transmission Control Module (TCM) Random Access Memory (RAM)

• P1621 -- Control Module Long Term Memory Performance

• P1621 -- Transmission Control Module (TCM) Long Term Memory Performance

Important:

• Use caution when diagnosing these shared codes to perform the appropriate diagnostic procedure on the appropriate module.

• A low voltage condition may set one or more of the above codes. Repair any low voltage conditions prior to diagnosing the above codes.


Refer to the appropriate Service Information (SI) document for Diagnosis and Repair procedures.



















DTC P0601, P0602, P0603, P0604, P0605, P0606, P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610
Description
This diagnostic applies to internal microprocessor integrity conditions within the engine control module (ECM). This diagnostic also addresses if the ECM is not programmed.

DTC Descriptors
This diagnostic procedure supports the following DTCs:

• DTC P0601 Control Module Read Only Memory (ROM)

• DTC P0602 Control Module Not Programmed

• DTC P0603 Control Module Long Term Memory Reset

• DTC P0604 Control Module Random Access Memory (RAM)

• DTC P1621 Control Long Term Memory Performance

• DTC P2610 Control Module Ignition Off Timer Performance

Conditions for Running the DTC
• DTC P0601, P0603, P0604, and P1621 run during power up.

• DTC P0602 and P2610 run continuously.

Conditions for Setting the DTC
These codes will set when there is incomplete programming or an internal failure within the ECM within 15 seconds.

Action Taken When the DTC Sets

DTC P0601, P0602, and P0604


• The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.

• The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.


DTC P0603 and P1621


• The control module stores the DTC information into memory when the diagnostic runs and fails.

• The MIL will not illuminate.

• The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.

• The driver information center (DIC), if equipped, may display a message.


DTC P2610


• The control module illuminates the MIL on the second consecutive ignition cycle that the diagnostic runs and fails.

• The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

DTC P0601, P0602, P0604, and P2610


• The control module turns OFF the MIL after 3 consecutive ignition cycles that the diagnostic runs and does not fail.

• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.

• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

• Clear the MIL and the DTC with a scan tool.


DTC P0603 and P1621


• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.

• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.

• Clear the DTC with a scan tool.

Test Description
The number below refers to the step number on the diagnostic table.

A DTC P0602 indicates the ECM is not programmed.

Step
Action
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
Is DTC P0602 set?
Go to Step 3
Go to Step 5

3
Program the engine control module (ECM). Refer to Service Programming System (SPS) in Programming and Setup.

Does DTC P0602 reset?
Go to Step 4
Go to Step 6

4
Ensure that all tool connections are secure.
Ensure that the programming equipment is operating correctly.
Ensure that the correct software/calibration package is used.
Attempt to program the ECM. Refer to Service Programming System (SPS) in Programming and Setup.
Does DTC P0602 reset?
Go to Step 5
Go to Step 6

5
Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?
Go to Step 6
--

6
Clear the DTCs with a scan tool.
Turn OFF the ignition for 30 seconds.
Start the engine.
Did the DTC fail this ignition?
Go to Step 2
Go to Step 7

7
Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?
Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information
System OK

thanksfor the reply. so i need to take it to the dealer and have it looked at

i have decided to take the truck in to the dealer. while its there im going to have them look at the powersteering box. it looks like it has a leak from the worm gear seal. this should be covered under warranty but my question is do i need to change the rims and tires out to get warranty work done. the tire size is 285/60/18. i wasnt sure of the issues that they would give me on that