III. Cooler Line Pressure Check

ROAD TEST, indicates the VCC is not applying because there is no rpm change when the VCC is commanded on and off.

Monitoring the transaxle outlet cooler line pressure while the VCC is commanded on and off will determine if the VCC apply valve is shifting.

FIGURE 5 - COOLER LINE PRESSURE CHECK - DEVILLE AND FLEETWOOD:

FIGURE 6 - COOLER LINE PRESSURE CHECK - ELDORADO AND SEVILLE:

Use the following procedure to determine if the VCC apply valve is shifting:

1. Install a 0-50 psi pressure gauge into the transaxle outlet line to the cooler. This line has a black check ball fitting at the transaxle and runs to the bottom fitting at the radiator, refer to Figure 5 for DeVilles and Fleetwoods, or Figure 6 for Eldorados and Sevilles.
2. Connect one end of a jumper wire to pin F of the ALDL connector (the wire should be long enough so the pressure gage can be read while grounding the opposite end the of wire).

3. Raise car on a hoist until the front wheels are off the ground.

4. Start engine, shift transaxle into D2 and run until a 1-2 upshift is obtained.

NOTE: D2 is used because second gear oil is required to shift the VCC apply valve and the ECM cannot command VCC on when the transaxle is in the D2 range.

FIGURE 3 - CODE E39 ELECTRICAL CHECK:

FIGURE 4 - ROAD TEST:

5. Monitor cooler line pressure, normally 25-30 psi (approximately 1/3 of line pressure). While in 2nd gear, ground the jumper wire to engage VCC and note the needle movement on the pressure gage.

^ Cooler line pressure reading decreases 1-2 psi (gage needle flickers) and then gradually increases to previous pressure each time pin F is grounded or opened - apply valve is shifting. If there were no electrical faults found in Figure 3 and Figure 4 indicated no rpm change, go to Section V - Viscous Converter Clutch Slippage.

^ Cooler line pressure reading does not change or flicker as pin F of the ALDL is grounded or opened - apply valve is not shifting, go to Section IV - VCC Apply Valve Does Not Move.

FIGURE 7 - VCC HYDRAULIC SCHEMATIC:

NOTE: The VCC apply valve is functioning normally when the pressure gage needle flickers 1-2 psi each time pin F of the ALDL is grounded or opened. The needle movement will appear to be a flicker rather than a direct pressure reading. This flicker is caused by a change in oil flow through the VCC apply valve to the cooler as the apply valve shifts. Refer to Figure 7 for a hydraulic schematic of the VCC system.