P1625

Circuit Description
The Shift Solenoids, the band apply solenoid, and the TCC solenoid are supplied power via the transmission power relay (internal to the TCM) on TCM terminal 53. The Pressure Control (PC) solenoid is also supplied power via the transmission power relay (internal to the TCM) but on TCM terminal 52. TCM terminals 52 and 53 are connected within the TCM. The TCM controls the solenoids by grounding the appropriate control circuit via internal solid state devices called drivers. The driver circuits have their own fault detection abilities that identity conditions with individual solenoids/circuits. The TCM also has fault detection circuitry for the power supply circuit that powers all of the solenoids in the transmission. If the TCM detects a condition with this circuit, DTC P1625 will set, and the TCM will shut off the transmission power relay. Any time a TCM DTC is set that requires the transmission to operate in default mode, the TCM turns off the power relay, effectively disabling all of the transmission components. Any time the default mode is in effect, the transmission line pressure is at maximum, the transmission starts in 4th gear, TCC is inhibited and the transmission adapt shift function is disabled.

When the TCM detects a power supply interrupt on TCM terminal 53, then DTC P1625 sets. DTC P1625 is a type B DTC

Condition for Running the DTC
The ignition switch is in the RUN position.

Condition for Setting the DTC
The TCM detects a short to ground or short to B+ on the power control relay circuit (terminal 53).

Action Taken When the DTC Sets
^ Early production - The TCM illuminates the service transmission lamp (STL) and sends a MIL request to the ECM on the second consecutive drive trip that the diagnostic runs and fails. The ECM then illuminates the MIL.
^ Late production - The TCM flashes the Sport Mode Lamp and sends a MIL request on the second consecutive drive trip that the diagnostic runs and fails. The TCM then illuminates the MIL.
^ The ECM records the operating conditions in the Freeze Frame at the time of the MIL request from the TCM.
^ The transmission operates in the default mode (maximum line pressure, command 4th gear, inhibit TCC, freeze shift adapts).

Conditions for Clearing the MIL/DTC
^ Early production - The TCM turns off the STL as soon as the fault is no longer present.
^ Late production - The TCM stops flashing the sport mode lamp as soon as the fault is no longer present.
^ The ECM turns off the MIL after three consecutive drive trips during which the TCM sends no MIL request.
^ A History DTC clears after forty consecutive warm-up cycles, if no failures are present by this diagnostic or any other emission related diagnostic.
^ The scan tool clears the MIL/DTC.
^ The TCM cancels the DTC default mode actions when the fault no longer exists and the ignition switch is Off long enough in order to power down the TCM.

Diagnostic Aids
Vehicles equipped with Fuel Cap Lamps utilize the Sport Mode lamp to indicate a transmission malfunction. In these vehicles, the Sport Mode Lamp flashes at 200 millisecond intervals when the TCM commands the lamp ON.

Vehicles not equipped with Fuel Cap Lamps are equipped with a dedicated Service Transmission Lamp (STL) on the Instrument Panel Cluster (IPC). The STL illuminates steadily when the TCM commands the lamp ON.

Use the J 35616-A connector test adapter kit for any test that requires probing the TCM harness connector or a component harness connector. Using this kit will prevent damage to the harness connector terminals.

Check for the following conditions:
^ Poor connections at the TCM or at the component. Inspect the harness connectors for any backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
^ Damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, observe the scan tool while moving any related connectors and any wiring harnesses. A change in the display may help to locate the fault.

Test Description
The number below refers to the step number on the Diagnostic Table.
6. This test determines if the transmission power relay output circuit is open between the TCM and the splice. For this DTC to set from an open circuit, the open would have to be between the TCM and the splice. An open in either of the circuits after the splice would set DTCs for the affected solenoids only.