Automatic Transaxle - 4T65-E - Service, Diagnosis & Troubleshooting: Diagnosis Chevrolet Uplander I

Circuit Description

The transmission internal mode switch (IMS) is a sliding contact switch attached to the selector detent inside the transmission side cover. The 4 inputs to the PCM indicate the position of the transmission range selector. The input voltage level at the PCM is high, B+, when the IMS is open and low when the switch is closed to ground. The 4 input parameters represented are Signals A, B, C and P, Parity. Refer to Transmission Internal Mode Switch Logic .

Road Test Procedure

The following test provides a method of evaluating the condition of the automatic transmission. The test is structured so that most driving conditions would be achieved. The test is divided into the following parts

1. Electrical Function Check
2. Upshift Control and Torque Converter Clutch (TCC) Apply
3. Part Throttle Detent Downshifts
4. Full Throttle Detent Downshifts
5. Manual Downshifts
6. Coasting Downshifts
7. Manual Gear Range Selection REVERSE Manual FIRST Manual SECOND Manual THIRD

Before the road test, ensure the following

1. The engine is performing properly.
2. Transmission fluid level is correct. Refer to the «Transmission Fluid Checking Procedure»(ref-241746-S15551101122006081100000) .
3. Tire pressure is correct.

During the road test

1. Perform the test only when traffic conditions permit.
2. Operate the vehicle in a controlled, safe manner.
3. Observe all traffic regulations.
4. View the scan tool data while conducting this test. Take along qualified help in order to operate the vehicle safely.
5. Observe any unusual sounds or smells.

After the road test, check the following

1. Transmission fluid level. Refer to the «Transmission Fluid Checking Procedure»(ref-241746-S15551101122006081100000) .
2. Diagnostic Trouble Codes (DTCs) that may have set during the testing. Refer to the applicable DTC.
3. Scan tool data for any abnormal readings or data.

Leak Test Procedure

1. Remove the solenoid from the control valve body. Refer to «1-2 Shift Solenoid Valve Replacement»(ref-241713-S05382487772006081100000) or «2-3 Shift Solenoid Valve Replacement»(ref-241713-S13961327412006081100000) .
2. Install the 1-2, 3-4 or the 2-3 shift solenoid valve into bore number 2 of the J 44246 and install the factory retainer clip to retain the solenoid. See «Special Tools»(ref-241713-S11115775082006081100000) .
3. Connect the solenoid testing harness supplied with the J 44246 to the solenoid. See «Special Tools»(ref-241713-S11115775082006081100000) .
4. Apply compressed air to the J 44246 . See «Special Tools»(ref-241713-S11115775082006081100000) .
5. Air should flow through the solenoid. If air does not flow through the solenoid, replace the solenoid.
6. Connect the solenoid testing harness to the (12 volt) positive and negative (-) battery terminals.
7. Observe if the solenoid is operating electrically. An audible clicking noise can be heard when connecting or disconnecting power.
8. Observe the air flow through the solenoid. The flow will completely or nearly completely stop. Replace the solenoid if there continues to be an obvious air leak when the solenoid is energized.
9. Install the solenoid into the control valve body. Refer to «1-2 Shift Solenoid Valve Replacement»(ref-241713-S05382487772006081100000) or «2-3 Shift Solenoid Valve Replacement»(ref-241713-S13961327412006081100000) .

Automatic Transmission Oil Cooler Flushing and Flow Test (J35944-A)

GM studies indicate that plugged or restricted transmission oil coolers and pipes cause insufficient transmission lubrication and elevated operating temperatures which can lead to premature transmission wear-out. Many repeat repair cases could have been prevented by following published procedures for transmission oil cooler flushing and flow checking. This procedure includes flow checking and flushing the auxiliary transmission oil cooler, if equipped.

Only GM Goodwrench DEXRON®VI automatic transmission fluid should be used when doing a repair on a GM transmission.

Time allowance for performing the cooler flow checking and flushing procedure has been included in the appropriate labor time guide operations since the 1987 model year. The service procedure steps for oil cooler flushing are as follows

Cooler Flow Check and Flushing Steps

1. Tools Required
2. Preparation
3. Back Flush
4. Forward Flush
5. Flow Check
6. Clean-up

Tools Required

1. J 35944-A Transmission Oil Cooler and Line Flusher. See «Special Tools»(ref-241713-S11115775082006081100000) .
2. J 35944-22 Transmission Oil Cooler Flushing Fluid. See «Special Tools»(ref-241713-S11115775082006081100000) .
3. Measuring cup
4. Funnel
5. Water supply - hot water recommended
6. Water hose, at least 16 mm (5/8 in) ID
7. Shop air supply with water/oil filters, regulator and pressure gage
8. Air chuck with clip, if available
9. Oil drain container
10. Pail with lid - 19 L (5 gallon)
11. Eye protection
12. Rubber gloves

Flow Test

1. Disconnect the hose from the oil cooler pipe. Connect the oil cooler feed pipe, top connector, to the transmission for normal flow.
2. Clip the discharge hose (1) to an empty oil container.
3. Confirm the transmission is filled with automatic transmission fluid. Refer to «Fluid Capacity Specifications»(ref-241713-S00195674212006081100000) for the correct automatic transmission fluid capacity.
4. Start the engine with the transmission in PARK range and run for 30 seconds after fluid begins to flow from the discharge hose (1). A minimum of 1.9 L (2 quarts) must be discharged during this 30 second run time.
5. If the fluid flow meets or exceeds 1.9 L (2 quarts) in 30 seconds, connect the oil cooler feed pipe to the front connector on the transmission.
6. If fluid flow is less than 1.9 L (2 qt) in 30 seconds, perform the following diagnosis: Disconnect the J 35944-A discharge hose (1) from the oil cooler return pipe. See «Special Tools»(ref-241713-S11115775082006081100000) . Disconnect the oil cooler feed pipe at the radiator. Connect the J 35944-A discharge hose (1) to the oil cooler feed pipe, radiator end. See «Special Tools»(ref-241713-S11115775082006081100000) . Clip the discharge hose (1) onto the oil drain container. Start the engine with the transmission in PARK range and run for 30 seconds after fluid begins to flow from the discharge hose (1). A minimum of 1.9 L (2 qt) must be discharged during this 30 second run time.
7. If the amount of transmission fluid flow remains less than 1.9 L (2 qt) in 30 seconds, inspect the oil cooler feed pipe, top connector, for restrictions or damage. If no condition is found with the feed pipe, inspect the transmission.

Automatic Transmission Oil Cooler Flushing and Flow Test (J45096)

GM studies indicate that plugged or restricted transmission oil coolers and pipes cause insufficient transmission lubrication and elevated operating temperatures which can lead to premature transmission failure. Many repeat repair cases could have been prevented by following published procedures for transmission oil cooler flushing and flow checking. This procedure includes flow checking and flushing the auxiliary transmission oil cooler, if equipped.

Only GM Goodwrench DEXRON®VI automatic transmission fluid should be used when doing a repair on a GM transmission.

Time allowance for performing the cooler flow checking and flushing procedure has been included in the appropriate labor time guide operations since the 1987 model year. The service procedure steps for oil cooler flushing and flow testing are as follows

1. Turn the main function switch to the FLOW position and allow the oil to flow for 15 seconds. Observe and note the flow rate; this is the TESTED flow rate.
2. Compare the TESTED flow rate to the MINIMUM flow rate information previously recorded. If the TESTED flow rate is equal to or greater than the MINIMUM flow rate recorded, the oil cooling system is functioning properly. Perform Code Recording Procedure. If the TESTED flow rate is less than the MINIMUM flow rate previously recorded, repeat the back flush and forward flush procedures.
3. If the TESTED flow rate is less than the MINIMUM flow rate after the second test, perform Code Recording Procedure. Replace the transmission oil cooler. Reconnect supply and waste hoses to the cooler lines in the normal flow direction. Perform Flow Test. Perform Code Recording Procedure.