A/T - A604 Electrical Solenoid Diagnosis
TRANSMISSION: Chrysler A-604BULLETIN: # 9001001
DATE: Jan 1990
SUBJECT: Electrical Diagnosis
Revised May 1990
(REVISED) CHRYSLER 604 SOLENOID DIAGNOSIS
The solenoid assembly (figure 1) for the Chrysler A-604 consists of 4 solenoids, 4 ball valves, 3 pressure switches and 3 resistors. The ball valves are operated by the solenoids and together they shift the transmission through the various gears and control lock up. The 3 pressure switches and resistors are used to signal the computer that a shift has occurred.
During rebuild or repair, the solenoid assembly should be checked for proper operation. This can be done through the 8 pin connector (figure 2). Refer to figure 3 for the function of each of the 8 pins.
CHECKING THE SWITCHES AND RESISTORS
To check the 3 switches and resistors use an ohmmeter set at ohms x 1 (RX1). Connect a lead from pin 4 to the solenoid housing (ground) then connect the two leads of the ohmmeter to pins 1 and 4 (see figure 2). The resistance should be 270-330 ohms. You have just checked the resistor for the overdrive pressure switch.
To check the switch, leave the ohmmeter connected and apply compressed air to the overdrive switch feed hole (See figure 4). The ohmmeter should read zero ohms resistance.
Now perform the same procedure at pins 2 and 4 for the low-reverse resistor and switch. Once again resistance should be 270-330 ohms (300 ohms = or -30) and go to zero ohms when the switch is pressurized. Use pins 3 and 4 to check the 2-4 pressure switch.
CHECKING THE SOLENOIDS
Each of the 4 solenoids should be checked next. Connect the ohmmeter leads to pins 4 and 5 to check the resistance of the underdrive solenoid. The resistance should be 1.5 ohms. (A digital ohmmeter works best for this test).
The other solenoids are checked in the same manner using pins 4 and 6, 4 and 7, and 4 and 8.
SHIFTING THE TRANSAXLE
Many times it is necessary to shift a transmission with jumper leads to determine if a problem is in the transmission or in the computer system. On the A-604 this can be done by providing 12 volts through a fused (20 amp) jumper wire to pin 4 (12 volt input) and grounding pins 6, 7, and 8 in the proper sequence.
RANGE GROUND THESE PINS
FIRST GEAR 7 AND 8
SECOND GEAR 0
THIRD GEAR 6 AND 8
FORTH GEAR 5 AND 6
LOCK-UP 7
If you supply 12 volts to pin 4 and then ground pins 7 and 8 the transaxle should be in 1st gear. Remove the grounds to shift to 2nd. Connect the grounds to pins 6 and 8 for 3rd gear. Grounding 5 and 6 will give you 4th gear. Anytime you're in 2nd, 3rd or 4th you can ground pin 7 for lock-up (TCC).
BULLETIN RECAP
CHRYSLER A-604 - Electrical Diagnosis
^ Check resistance at pins 1 and 4, 2 and 4, and 3 and 4 (Resistance should be 270-330 ohms)
^ Air check the feed holes for each of the switches (Resistance should go to zero ohms as each switch is closed)
^ Check solenoid resistance at pins 4 and 5, 4 and 6, 4 and 7; and 4 and 8 (Resistance should be 1.5 ohms)
^ Shift the transaxle electrically
FOR ADDITIONAL INFORMATION:
Transmission Digest
September '89, Page 6
October '89, Page 6
December '88, Page 26