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Test Description

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

  1. 2:  HI values for all signals in all ranges indicates the ground circuit is OPEN.
  2. 3:  With the 20-way connector disconnected, all signals should indicate HI.
  3. 5:  If one circuit affects the other, this indicates a short between the two circuits.
  4. 11:  This step tests the internal transmission harness. If no fault is found in the harness, the fault will be in the switch.
Range Selector Displays Incorrect Range

Step Action Value(s) Yes No
1
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Select IMS on the scan tool.
  4. Place the range selector in each transmission range: P, R, N, D4, D3, D2 and D1.
Does each range selected match the scan tool IMS display?		 - Go to Powertrain Control Module (PCM) Replacement in Engine Controls - 3.1L or Intermittent Conditions in Engine Controls - 3.8L Go to Step 2 
2 
  1. Select IMS A/B/C/P on the scan tool.
  2. Place the range selector in each transmission range: P, R, N, D4, D3, D2 and D1.
Does the IMS A/B/C/P display the specified values for each range?		 HI/HI/HI/HI Go to Step 12  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.
Do the scan tool IMS A/B/C/P signals all indicate HI?		 - Go to Step 4  Go to Step 8 
4
  1. Turn OFF the ignition.
  2. Install the J 44152  jumper harness on the engine side of the AT Inline 20-way connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Using the J 39200  digital multimeter (DMM) and the J 35616  GM terminal test kit, measure the voltage at terminal F of the J 44152  .

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

  5. Measure the voltage at terminal G of the J 44152  .
  6. Measure the voltage at terminal H of the J 44152  .
  7. Measure the voltage at terminal J of the J 44152  .
Does the voltage measure ignition voltage at all four terminals?		 - Go to Step 5  Go to Step 9 
5  Connect a fused jumper wire from terminal F of the J 44152  signal A circuit to ground while monitoring the scan tool IMS A/B/C/P parameter.
Refer to Automatic Transmission Inline 20-Way Connector End View .
When signal A circuit is grounded, do any other signal circuits indicate LOW?		 - Go to Step 10  Go to Step 6 
6 Connect a fused jumper wire from terminal G of the J 44152  signal B circuit to ground while monitoring the scan tool IMS A/B/C/P parameter.
Refer to Automatic Transmission Inline 20-Way Connector End View .
When signal B circuit is grounded, do any other signal circuits indicate LOW?		 - Go to Step 10  Go to Step 7 
7 Connect a fused jumper wire from terminal H of the J 44152  signal C circuit to ground while monitoring the scan tool IMS A/B/C/P parameter.
Refer to Automatic Transmission Inline 20-Way Connector End View .
When signal C circuit is grounded, do any other signal circuits indicate LOW?		 - Go to Step 10  Go to Step 11 
8 Test the signal circuits of the IMS that did not indicate HI for a short to ground between the PCM and the AT Inline 20-way connector.
Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 17  Go to Step 16 
9 Test the signal circuits of the IMS that did not indicate ignition voltage for an open between the PCM and the AT Inline 20-way connector.
Refer to Testing for Continuity andWiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 17  Go to Step 16 
10 Test the affected signal circuits of the IMS for a shorted together condition between the PCM and the AT Inline 20-way connector.
Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 17  Go to Step 16 
11  Test the signal circuits of the IMS for an open or shorted condition between the AT Inline 20-way connector and the IMS.
Refer to Circuit Testing in Wiring Systems.
Did you find the condition?		 - Go to Step 14  Go to Step 15 
12 Test the ground circuit of the IMS for an open between the AT Inline 20-way connector and the ground connection to the chassis.
Refer to Testing for Continuity andWiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 17  Go to Step 13 
13 Test the ground circuit of the IMS for an open between the AT Inline 20-way connector and the IMS.
Refer to Testing for Continuity in Wiring Systems.
Did you find the condition?		 - Go to Step 14  Go to Step 15 
14 Replace the automatic transmission wiring harness assembly.
Refer to Wiring Harness Replacement .
Did you complete the replacement?		 - Go to Step 17  -
15 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 Unit Repair article.
Did you complete the replacement?		 - Go to Step 17  -
16 Replace the PCM.
Refer to Intermittent Conditions in Engine Controls - 3.1L or Powertrain Control Module (PCM) Replacement in Engine Controls - 3.8L.
Did you complete the replacement?		 - Go to Step 17  -
17
  1. Turn ON the ignition, with the engine OFF.
  2. With the scan tool, observe the IMS display while selecting each transmission range: P, R, N, D4, D3, D2, and D1.
Does each selected transmission range match the scan tool IMS display?		 - System OK Go to Step 1 
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