Symptoms - Automatic Transmission
| Diagnostic Category | Diagnostic Information |
|---|---|
| This table consists of nine diagnostic categories that are located in the left 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 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 Oil Pressure High or Low . Refer to Fluid Leak Diagnosis , procedure. Refer to Oil Out the Vent . |
| Noise and Vibration Diagnosis: This category contains the following topics: Ratcheting noise Noise - drive gear, final drive, whine, growl, rattle, buzz, popping Vibration | Refer to Ratcheting Noise . Refer to Vibration in Reverse and Whining Noise in Park . Refer to Popping Noise . Refer to Whine Noise Varying with RPM or Fluid Pressure . Refer to Buzz Noise or High Frequency Rattle Sound . Refer to Noise in Random Ranges . |
| Range Performance Diagnosis: This category contains the following topics: Drives in Neutral No Park No Reverse No Drive No engine braking Shift selector indicator does not match transmission gear range Lack of Power or Hesitation | Refer to Drives in Neutral . Refer to No Park . Refer to No Reverse or Slips in Reverse . Refer to No Drive in All Ranges . Refer to No Drive in Drive Range . Refer to No Overrun Braking - Manual 3-2-1 . Refer to Range Selector Displays Incorrect Range . Refer to Lack of Power or Hesitation . |
| Shift Quality (Feel) Diagnosis: This category contains the following topics: Harsh, soft or slipping shifts Harsh, soft or delayed engagement Shift shudder, flare or tie-up | Refer to Harsh Shifts . Refer to Slipping or Harsh 1-2 Shift . Refer to No 2-3 Shift or 2-3 Shift Slips, Rough or Hunting . Refer to No 3-4 Shift, Slips or Rough 3-4 Shift . Refer to Harsh Garage Shift . Refer to Delay in Drive and Reverse . Refer to 3-2 Flare or Tie-Up . |
| Shift Pattern: This category contains the following topics: One forward gear only Two forward gears only Gear missing or slipping No upshift or slipping upshift No downshifts Non-First gear start | Refer to First Gear Range Only - No Upshift . Refer to Third Gear Only . Refer to Second/Third Gear Only or First/Fourth Gears Only . Refer to Slips in First Gear . Refer to Slipping or Harsh 1-2 Shift . Refer to No 2-3 Shift or 2-3 Shift Slips, Rough or Hunting . Refer to No 3-4 Shift, Slips or Rough 3-4 Shift . Refer to No Part Throttle or Delayed Downshifts . Refer to Second Gear Start . |
| Shift Speed Diagnosis: This category contains the following topic: Inaccurate or inconsistent shift points | Refer to Inaccurate Shift Points . |
| Torque Converter Diagnosis: This category contains the following topics: Torque converter diagnosis TCC does not apply TCC does not release TCC apply/release quality | Refer to Torque Converter Diagnosis Procedure . Refer to No Torque Converter Clutch (TCC) Apply (300 RPM Slip) . Refer to No Torque Converter Clutch (TCC) Release . Refer to Torque Converter Clutch (TCC) Shudder . |
| Indicator On or Message Center Displays Message: This category contains the following topics: 4WD light does not illuminate Tow/haul light does not illuminate Message Center displays "Trans Fluid Hot" Message Center displays "Trans Hot...Idle Engine" | Refer to DTC P2771 . Refer to Tow/Haul Switch/Indicator Always On or Inoperative . Refer to Transmission Fluid Checking Procedure . Refer to Transmission Overheats . |
| If symptom is not found | Refer to Transmission Fluid Checking Procedure . Refer to Road Test Procedure (M30/M32) Road Test Procedure (M33 Only) . Refer to Line Pressure Check Procedure (M30/M32) Line Pressure Check Procedure (M33 Only) . |
Symptom Diagnosis
Scheme 459
Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 4: By disconnecting the TR switch, the ground path of all TR switch circuits is removed and the PCM should recognize all circuits as open. The scan tool should display HI for all range signal states.
- 5: This step tests the TR switch wiring for an open or the lack of the signal voltage from the PCM.
- 6: This step tests the TR switch wiring and the PCM by providing a ground path through a fused jumper wire. When grounded, the scan tool range signal states should change to LOW.
- 7: This step tests the TR switch wiring and the PCM by providing a ground path through a fused jumper wire. When grounded, the scan tool range signal states should change to LOW.
- 8: This step tests the TR switch wiring and the PCM by providing a ground path through a fused jumper wire. When grounded, the scan tool range signal states should change to LOW.
- 9: This step tests the TR switch wiring and the PCM by providing a ground path through a fused jumper wire. When grounded, the scan tool range signal states should change to LOW.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Install a scan tool. Turn ON the ignition, with the engine OFF. Select TR Sw. on the scan tool. With the scan tool, observe the TR Sw. display while selecting each transmission range: P, R, N, D4, D3, D2, and D1. Does each selected transmission range match the scan tool TR Sw. display? | Go to Step 2 | Go to Step 3 | |
| 2 | Observe the IPC gear range display while selecting each transmission range: P, R, N, D4, D3, D2, D1. Does each selected transmission range match the IPC display? | Go to Intermittent Conditions in Engine Controls - 4.3L or Intermittent Conditions in Engine Controls - 4.8L, 5.3L and 6.0L | Go to Step 16 | |
| 3 | With the scan tool, observe the TR Sw. A/B/C/P display. Does the scan tool TR Sw. A/B/C/P parameter indicate HI for all range signal states? | Go to Step 13 | Go to Step 4 | |
| 4 | Turn OFF the ignition. Disconnect the TR switch connector. Turn ON the ignition, with the engine OFF. Does the scan tool TR Sw. A/B/C/P parameter indicate HI for all range signal states? | Go to Step 5 | Go to Step 10 | |
| 5 | Using the DMM and the J 35616 GM Terminal Test Kit, measure the voltage from the signal A circuit of the TR switch connector to ground. Measure the voltage from the signal B circuit of the TR switch connector to ground. Measure the voltage from the signal C circuit of the TR switch connector to ground. Measure the voltage from the signal P circuit of the TR switch connector to ground. Does the voltage measure within the specified value at all four terminals? | 10-12 V | Go to Step 6 | Go to Step 11 |
| 6 | Connect a fused jumper wire from the TR switch connector, signal circuit A, to ground while monitoring the scan tool TR Sw. A/B/C/P parameter. When signal circuit A is grounded, do any other signal circuits indicate LOW? | Go to Step 12 | Go to Step 7 | |
| 7 | Connect a fused jumper wire from the TR switch connector, signal circuit B, to ground while monitoring the scan tool TR Sw. A/B/C/P parameter. When signal circuit B is grounded, do any other signal circuits indicate LOW? | Go to Step 12 | Go to Step 8 | |
| 8 | Connect a fused jumper wire from the TR switch connector, signal circuit C, to ground while monitoring the scan tool TR Sw. A/B/C/P parameter. When signal circuit C is grounded, do any other signal circuits indicate LOW? | Go to Step 12 | Go to Step 9 | |
| 9 | Connect a fused jumper wire from the TR switch connector, signal circuit P, to ground while monitoring the scan tool TR Sw. A/B/C/P parameter. When signal circuit P is grounded, do any other signal circuits indicate LOW? | Go to Step 12 | Go to Step 13 | |
| 10 | Test the signal circuits of the TR switch that did not indicate HI for a short to ground. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 17 | Go to Step 15 | |
| 11 | Test the signal circuits of the TR switch that did not indicate proper voltage for an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 17 | Go to Step 15 | |
| 12 | Test the affected signal circuits of the TR switch for a shorted together condition. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 17 | Go to Step 15 | |
| 13 | Test the ground circuit of the TR switch for an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 17 | Go to Step 14 | |
| 14 | Replace the TR switch. This switch is part of the park/neutral position switch. Refer to Park/Neutral Position Switch Replacement . Did you complete the replacement? | Go to Step 17 | ||
| 15 | Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement in Engine Controls - 4.3L or Powertrain Control Module (PCM) Replacement in Engine Controls - 4.8L, 5.3L and 6.0L. Did you complete the replacement? | Go to Step 17 | ||
| 16 | Replace the IPC. Refer to Instrument Panel Cluster (IPC) Replacement in Instrument Panel, Gages and Console. Did you complete the replacement? | Go to Step 17 | Go to Step 2 | |
| 17 | Turn ON the ignition, with the engine OFF. With the scan tool, observe the TR Sw. display while selecting each transmission range: P, R, N, D4, D3, D2 and D1. Does each selected transmission range match the scan tool TR Sw. display? | System OK | Go to Step 2 |
Range Selector Displays Incorrect Range
Scheme 460
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step tests for a faulty tow/haul switch.
- 3: This step tests for voltage input from the BCM to the tow/haul switch.
- 6: This step tests for ground integrity.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Install a scan tool. Turn ON the ignition, with the engine OFF. Cycle the tow/haul switch while observing Tow/Haul Mode on the scan tool. Does the scan tool display Active when the switch is first pressed, and then Inactive when the switch is pressed again? | Go to Intermittent Conditions in Engine Controls - 4.3L or Intermittent Conditions in Engine Controls - 4.8L, 5.3L and 6.0L | Go to Step 2 | |
| 2 | Remove the connector from the tow/haul switch. Using the J 35616 GM Terminal Test Kit, install a fused jumper wire from the tow/haul switch signal and ground circuits of the tow/haul switch connector. Does the scan tool Tow/Haul Mode indicate a status change? | Go to Step 7 | Go to Step 3 | |
| 3 | Using the DMM and the J 35616 , measure the voltage at the tow/haul switch signal circuit of the tow/haul switch connector. Is ignition voltage measured? | Go to Step 6 | Go to Step 4 | |
| 4 | Using the DMM and the J 35616 , measure the voltage at the tow/haul switch signal circuit of the body control module (BCM). Is ignition voltage measured? | Go to Step 5 | Go to Step 8 | |
| 5 | Test the signal circuit of the tow/haul switch for an open or shorted condition. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Intermittent Conditions in Engine Controls - 4.3L or Intermittent Conditions in Engine Controls - 4.8L, 5.3L and 6.0L | |
| 6 | Test the ground circuit of the tow/haul switch for an open or shorted condition. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Intermittent Conditions in Engine Controls - 4.3L or Intermittent Conditions in Engine Controls - 4.8L, 5.3L and 6.0L | |
| 7 | Replace the tow/haul switch. Refer to Shift Lever Replacement (With Tow/Haul Switch) Shift Lever Replacement (Without Tow/Haul Switch) in Steering Wheel and Column. Did you complete the replacement? | Go to Step 9 | ||
| 8 | Test the BCM for proper operation. Refer to Diagnostic Starting Point - Body Control System in Body Control System. Did you find and correct the condition? | Go to Step 9 | ||
| 9 | After the repair is complete, observe Tow/Haul Mode on the scan tool display, while cycling the tow/haul switch. Does the scan tool display Active when the switch is first pressed, and then Inactive when the switch is pressed again? | System OK | Go to Step 1 |
Tow/Haul Switch/Indicator Always On or Inoperative