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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 P1823 (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 numbers below refer to the step numbers on the diagnostic table.

  1. 3:  A LOW signal indicates a short to ground in the vehicle harness or the TCM.
  2. 5:  This step tests the internal transmission harness without the IMS connected.
DTC P1823 (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 the 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. Turn ON the ignition, with the engine OFF.
  4. Select IMS A/B/C/P on the scan tool.
Does IMS signal P indicate LOW?		 - Go to Step 4  Go to Step 5 
4 Test the TR signal P circuit of the IMS for a short to ground between the TCM connector and the AT Inline 20-way connector.
Refer to Testing for Short to Ground and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 9  Go to Step 8 
5 
  1. Turn OFF the ignition.
  2. Reconnect the AT Inline 20-way connector.
  3. Disconnect the automatic transmission wiring harness at the IMS.
  4. Turn ON the ignition, with the engine OFF.
  5. Select IMS A/B/C/P on the scan tool.
Does IMS signal P indicate LOW?		 - Go to Step 6  Go to Step 7 
6 Replace the automatic transmission wiring harness assembly.
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 4 seconds or more.
  4. Select IMS A/B/C/P on the scan tool.
  5. Move the range selector from PARK to D4.
  6. Ensure that IMS signal P changes from LOW to HI for 4 seconds or more.
  7. Select Specific DTC.
  8. Enter DTC P1823.

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
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