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Home >> Buick >> 2007 >> Lucerne CX >> Repair and Diagnosis >> External Pages >> Different car >> Section 184 (Automatic Transaxle - 4T65-E - DTC P0218 To DTC P0748) >> DTC P0723 (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:  This step tests the ability of the VSS to produce an AC voltage. This step also verifies the integrity of the wiring to the TCM.
  2. 4:  This step tests the VSS circuit for correct resistance.
DTC P0723 (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 switch with the engine OFF.
    3. IMPORTANT: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. Using the Clear Info function will erase the stored Freeze Frame and Failure Records from the TCM.
  3. Record the Freeze Frame and Failure Records.
  4. Clear the DTCs.
    5. NOTE: Support the lower control arms in the normal horizontal position in order to avoid damage to the drive axles. Do not operate the vehicle in gear with the wheels hanging down at full travel.
  5. Raise and support the drive wheels.
  6. Start and idle the engine.
  7. Place the transmission in DRIVE.
  8. Monitor Transmission OSS on the scan tool.
  9. With the drive wheels rotating, increase and decrease the throttle position.
Does the Transmission OSS RPM increase when wheel speed increases?		 - Go to Testing for Intermittent Conditions and Poor Connections Go to Step 3 
3 
  1. Turn OFF the ignition.
  2. Disconnect the TCM connector.
  3. Using the J 35616  GM terminal test kit, connect the DMM to the VSS high signal and the VSS low signal of the TCM harness connector.
  4. Select AC volts on the DMM.
  5. Turn ON the ignition with the engine OFF.
  6. Place the range selector in a DRIVE range or NEUTRAL.
  7. Rotate the right front drive wheel by hand, while observing the DMM display.
Does the voltage measure greater than the specified value?		 0.4 volts AC Go to Step 8  Go to Step 4 
4 
  1. Leave the DMM test leads connected to the VSS high signal and the VSS low signal of the TCM harness connector.
  2. Select ohms on the DMM.
  3. Measure the resistance of the complete VSS circuit.
Is the circuit resistance within the specified range?		 1650-3180 Ω Go to Step 9  Go to Step 5 
5 Is the circuit resistance greater than the specified value? 3180 Ω Go to Step 11  Go to Step 6 
6
  1. Leave the DMM test leads connected between the VSS high signal and the VSS low signal of the TCM harness connector.
  2. Disconnect the VSS connector at the transmission.
  3. Test the high signal circuit and the low signal circuit of the VSS for a short together.

    Refer to Circuit Testing .

Are the signal and ground circuits shorted together?		 - Go to Step 7  Go to Step 14 
7 Repair the short between the high signal circuit and the low signal circuit.
Refer to Wiring Repairs .
Did you complete the repair?		 - Go to Step 16  -
8 Test the high signal circuit of the VSS for a short to ground between the TCM and the VSS.
Refer to Testing for Short to Ground and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 16  Go to Step 15 
9
  1. Reconnect the TCM connector.
  2. Select DC volts on the DMM.
  3. Using the J 35616  connect the DMM to the VSS of the vehicle harness.
  4. Turn ON the ignition with the engine OFF.
Does the DMM display greater than the specified voltage?		 1.0 V Go to Step 10  Go to Step 13 
10 Repair the short to voltage in the high signal circuit.
Refer to Wiring Repairs .
Did you complete the repair?		 - Go to Step 16  -
11 Test the high signal circuit of the VSS for an open between the TCM and the VSS.
Refer to Testing for Continuity and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 16  Go to Step 12 
12 Test the low signal circuit of the VSS for an open between the TCM and the VSS.
Refer to Testing for Continuity and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 16  Go to Step 14 
13
  1. Remove the VSS.

    Refer to Vehicle Speed Sensor (VSS) Replacement .

  2. Inspect the VSS and the transmission for the following:
    • Incorrect VSS
    • VSS damage
    • Excessive runout in the final drive carrier assembly
    • Excessive VSS to speed sensor rotor gap
    • Incorrect speed sensor rotor alignment
    • Speed sensor rotor damage
  3. Repair any of the above items as necessary.
Refer to DIFFERENTIAL CARRIER INSPECTION (FWD ONLY) in Transmission Overhaul article.Did you find and correct the condition?		 - Go to Step 16  Go to Step 14 
14 Replace the VSS.
Refer to Vehicle Speed Sensor (VSS) Replacement .
Did you complete the replacement?		 - Go to Step 16  -
15 Replace the TCM.
Refer to Control Module References for replacement, setup and programming.
Did you complete the replacement?		 - Go to Step 16  -
16 Perform the following procedure in order to verify the repair:
  1. Select DTC.
  2. Select Clear Info.
  3. Drive the vehicle.
  4. Ensure that the transmission OSS is greater than 500 RPM and no drop in OSS greater than 175 for at least 3 seconds.
  5. Select Specific DTC.
  6. Enter DTC P0723.

Has the test run and passed?		 - Go to Step 17  Go to Step 2 
17 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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