Symptoms - Automatic Transmission
| Diagnostic Category | Diagnostic Information |
|---|---|
| DEFINITION: This table consists of eight diagnostic categories that are located in the left-hand column. Using this column, choose the appropriate category based on the operating conditions of the vehicle or transmission. After selecting a category, use the right-hand column to locate the specific symptom diagnostic information. | |
| Fluid Diagnosis: This category contains the following topics: Fluid condition - appearance, contaminants, smell, overheating Line pressure - high or low Fluid leaks | Refer to Transmission Fluid Checking Procedure . Refer to Incorrect Line Pressure . Refer to Automatic Transmission Fluid Leaks . Refer to Fluid Leak Diagnosis . Refer to Case Porosity Repair . |
| Noise and Vibration Diagnosis: This category contains the following topics: Noise - drive gear, final drive, whine, growl, hum, rattle, buzz, popping Torque converter diagnosis Noise and vibration analysis | Refer to Whine Noise Varying with RPM or Fluid Pressure . Refer to Popping Noise . Refer to Buzz Noise or High Frequency Rattle Sound . Refer to Whine/Growl Noise That Changes with Vehicle Speed . Refer to Final Drive Noise or Hum Noise . Refer to Noise in First, Second, Third or Fourth . Refer to Noise in Random Ranges . Refer to Abnormal Noise in Park or Neutral Range . Refer to Torque Converter Diagnosis Procedure . Refer to Noise and Vibration Analysis . |
| Range Performance Diagnosis: This category contains the following topics: No Park No Reverse or slips No Drive or slips No engine braking Range selector displays incorrect range | Refer to No Park Range . Refer to Slips in Reverse or No Reverse . Refer to Slips in Drive or No Drive . Refer to Locked Up in Drive/Reverse . Refer to No Engine Braking in Manual Second or Low Range . Refer to Range Selector Displays Incorrect Range (3.5L) or Range Selector Displays Incorrect Range (3.9L) . |
| Shift Quality (Feel) Diagnosis: This category contains the following topics: Harsh shifts Soft shifts Harsh engagement, garage shifts Delayed engagement, garage shifts | Refer to Harsh or Soft 1-2 Shift Feel . Refer to Harsh or Soft 2-3/3-2 Shift Feel . Refer to Harsh or Soft 3-4/4-3 Shift Feel . Refer to Harsh Park to Reverse/Drive Engagement . Refer to Delayed Park to Reverse/Drive Engagement . |
| Slipping or Missing Gears: This category contains the following topics: No upshift Slipping or missing gears One forward gear only Two forward gears only Non-First gear start | Refer to Slipping or No First Gear . Refer to Slipping or No Second Gear . Refer to Slipping or No Third Gear . Refer to Slipping or No Fourth Gear . Refer to First Gear Only . Refer to Second Gear Only . Refer to Third Gear Only . Refer to Fourth Gear Only . Refer to First and Second Gear Only (2-3 Solenoid Stuck On) . Refer to First and Fourth Gear Only (1-2 Solenoid Stuck On) . Refer to Second and Third Gear Only (1-2 Solenoid Stuck Off) . Refer to Third and Fourth Gear Only (2-3 Solenoid Stuck Off) . |
| Shift Speed Diagnosis: This category contains the following topic: Incorrect shift points | Refer to High or Low Upshift or Downshift Speed . |
| Torque Converter Diagnosis: This category contains the following topics: Torque converter diagnosis TCC does not apply TCC does not release TCC shudder | Refer to Torque Converter Diagnosis Procedure . Refer to No Torque Converter Clutch (TCC) Apply . Refer to Converter Clutch Stuck On in All Gears . Refer to Converter Clutch Stuck On in Second, Third and Fourth Gear . Refer to Harsh Torque Converter Clutch (TCC) Apply or Release . Refer to Converter Clutch Apply Rough, Slips or Shudders . |
| Symptom Can Not Be Duplicated or Symptom Not Found: This category contains the following topics: Transmission fluid diagnosis Road testing Line pressure diagnosis | Refer to Transmission Fluid Checking Procedure . Refer to Road Test Procedure . Refer to Line Pressure Check Procedure . |
Symptoms - Automatic Transmission
Scheme 90
Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 2: HI values for all signals in all ranges indicates the ground circuit is OPEN.
- 3: With the 20-way connector disconnected, all signals should indicate HI.
- 5: If a circuit affects the other, this indicates a short between the 2 circuits.
- 11: This step tests the internal transmission harness. If no fault is found in the harness, the fault will be in the switch.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| 1 | Install a scan tool. Turn ON the ignition, with the engine OFF. Select IMS on the scan tool. 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 Testing for Intermittent Conditions and Poor Connections | Go to Step 2 | |
| 2 | Select IMS A/B/C/P on the scan tool. 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 | Turn OFF the ignition. Disconnect the AT Inline 20-way connector. Additional DTCs may set. Turn ON the ignition, with the engine OFF. 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 | Turn OFF the ignition. Install the J 44152 jumper harness on the engine side of the AT Inline 20-way connector. See Special Tools . Turn ON the ignition, with the engine OFF. Using the J 39200 digital multimeter (DMM) and the J 35616 GM terminal test kit, measure the voltage at the TR signal A circuit of the J 44152 . See Special Tools . Refer to Automatic Transmission Inline 20-Way Connector End View . Measure the voltage at the TR signal B circuit of the J 44152 . See Special Tools . Measure the voltage at the TR signal C circuit of the J 44152 . See Special Tools . Measure the voltage at the TR signal P circuit of the J 44152 . See Special Tools . 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 the TR signal A circuit of the J 44152 to ground while monitoring the scan tool IMS A/B/C/P parameter. See Special Tools . Refer to Automatic Transmission Inline 20-Way Connector End View . When the TR 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 the TR signal B circuit of the J 44152 to ground while monitoring the scan tool IMS A/B/C/P parameter. See Special Tools . Refer to Automatic Transmission Inline 20-Way Connector End View . When the TR 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 the TR signal C circuit of the J 44152 to ground while monitoring the scan tool IMS A/B/C/P parameter. See Special Tools . Refer to Automatic Transmission Inline 20-Way Connector End View . When the TR signal C circuit is grounded, do any other signal circuits indicate LOW? | Go to Step 10 | Go to Step 11 | |
| 8 | Test the TR 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 . Did you find and correct the condition? | Go to Step 17 | Go to Step 16 | |
| 9 | Test the TR 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 and Wiring Repairs . Did you find and correct the condition? | Go to Step 17 | Go to Step 16 | |
| 10 | Test the affected TR 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 . Did you find and correct the condition? | Go to Step 17 | Go to Step 16 | |
| 11 | Test the TR 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 . 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 and Wiring Repairs . 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 . 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 Overhaul article. Did you complete the replacement? | Go to Step 17 | ||
| 16 | Replace the PCM. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement? | Go to Step 17 | ||
| 17 | Turn ON the ignition, with the engine OFF. 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 |
Range Selector Displays Incorrect Range (3.5L)