W T E C I I I E L E C T R O N I C C O N T R O L S T R O U B L E S H O O T I N G M A N U A L
Figure 519. Solenoid Resistance vs. Temperature
1. Check the transmission connector and make sure it is tightly connected. If the connector is
properly connected, disconnect the harness at the feedthrough harness connector and check the
terminals in the transmission harness and feedthrough harness connectors.
2. If the connector is connected, clean, and not damaged, check the solenoid circuit in the transmis-
sion for opens. Refer to the system schematic and/or chart to identify wires in the internal har-
ness which are connected. If the open circuit is found, drain the fluid, remove the control
module (see the transmission Service Manual), and isolate the open. The fault will be in the
feedthrough harness or the solenoid itself (see Figure 51 for solenoid locations).
3. If the open is not found at the transmission connector, disconnect the transmission harness
connector at the ECU and inspect the terminals in the connector and the ECU for damage or
contamination. Clean or replace as necessary. If the terminals are satisfactory, check the wires of
the solenoid circuit in the transmission harness for continuity. If the open is found in one of the
wires, isolate and repair it. If this is not feasible, use a spare wire, if available, or provide a new
wire (St. Clair P/N 200153 may be used for this purpose).
4. If multiple code 45s occur (4512, 4513, 4514, 4515, 4516, 4522, and 4524), and wiring and
solenoids check okay, the A-Hi driver is probably failed open.
5. Replace the ECU. If replacing the ECU corrects the problem, reinstall the original (bad) ECU to
confirm that the problem is in the ECU. If the problem recurs, reinstall the new ECU to complete
6. If code 4521 occurs repeatedly and the F solenoid and wiring checks okay, the F-Hi or F-Lo driver
may be failed open. Follow Step (5) above.
CODE 45 XX OPEN CONDITION IN SOLENOID CIRCUIT (Figure 519)