LEMON Manuals: Even more car manuals for everyone
Home >> Buick >> 2007 >> Lucerne CX >> Repair and Diagnosis >> External Pages >> Different car >> Section 234 (Automatic Transaxle - 4T65-E - DTC P1823 (3.9L) To DTC P2764) >> DTC P1826 (3.9L) >> Test Description

Test Description

WARNING: This page is about a different car, the 2006 Pontiac Montana SV6, 2006 Chevrolet Uplander, and 2006 Buick Terraza. However, it is still accessible from the selected car via links, so may be relevant.

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

  1. 3:  This step tests the integrity of the engine harness and TCM by checking for the Signal C state change from HI to LOW. A LOW signal indicates the fault is either in the internal transmission harness or the switch. A HI signal indicates the fault is either in the engine harness or the TCM.
DTC P1826 (3.9L)

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
2
  1. Install a scan tool.
  2. Turn ON the ignition with the engine OFF.
    3. IMPORTANT: Before clearing the DTC, use the scan tool in order to record the Failure Records. Using the Clear Info function erases Failure Records from the TCM.
  3. Record the DTC Freeze Frame and Failure Records.
  4. Clear the DTC.
  5. Select IMS on the scan tool.
  6. Place the range selector in D4.
Does the scan tool IMS parameter indicate Drive 4?		 - Go to Testing for Intermittent Conditions and Poor Connections Go to Step 3 
3 
  1. Turn OFF the ignition.
  2. Disconnect the AT Inline 20-way connector. Additional DTCs may set.
  3. Install the J 44152  jumper harness on the engine side of the AT Inline 20-way connector. See Special Tools .
  4. Using the J 35616  GM terminal test kit, connect a fused jumper wire from the TR signal C circuit of the J 44152  to a good ground. See Special Tools .

    Refer to Automatic Transmission Inline 20-Way Connector End View .

  5. Turn ON the ignition, with the engine OFF.
  6. Select IMS A/B/C/P on the scan tool.
Does IMS Signal C indicate LOW?		 - Go to Step 5  Go to Step 4 
4 Test the TR signal C circuit of the IMS for an open between the TCM connector and the AT Inline 20-way connector.
Refer to Testing for Continuity and Wiring Repairs .
Did you find and correct a condition?		 - Go to Step 9  Go to Step 8 
5 Test the TR signal C circuit of the IMS for an open between the AT Inline 20-way connector and the IMS.
Refer to Testing for Continuity .
Did you find the condition?		 - Go to Step 6  Go to Step 7 
6 Replace the automatic transmission wiring harness.
Refer to Wiring Harness Replacement .
Did you complete the replacement?		 - Go to Step 9  -
7 Replace the lever assembly-manual shaft detent with internal mode switch.
Refer to MANUAL SHIFT SHAFT POSITION (INTERNAL MODE) SWITCH AND PARKING SYSTEM COMPONENTS REMOVAL in Transmission Overhaul article.
Did you complete the replacement?		 - Go to Step 9  -
8 Replace the TCM.
Refer to Control Module References for replacement, setup and programming.
Did you complete the replacement?		 - Go to Step 9  -
9 Perform the following procedure in order to verify the repair:
  1. Select DTC.
  2. Select Clear Info.
  3. Start and idle the engine in PARK for 10 seconds.
  4. Observe IMS A/B/C/P on the scan tool.
  5. Move the range selector to D1, D2, D3 and D4 positions. Ensure that IMS Signal C indicates LOW for each range.
  6. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
  7. Select Specific DTC.
  8. Enter DTC P1826.

Has the test run and passed?		 - Go to Step 10  Go to Step 2 
10 With a 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 System OK
scientia non olet · About LEMON Manuals