Circuit Description
The transmission control module (TCM) provides voltage to the pressure control solenoid, the shift solenoids, the band apply solenoid, and the TCC solenoid through an internal power control relay. A normal function of the TCM is to run tests on the power control relay to ensure that it is functioning properly. The power control relay has two output terminals on the TCM. The pressure control solenoid signal circuit receives voltage from TCM terminal 52. The other solenoids receive voltage from TCM terminal 53. TCM terminals 52 and 53 are connected inside the TCM.
When the TCM detects a continuous open circuit at TCM terminals 52 and 53, then DTC P1800 sets. DTC P1800 is a type B DTC.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | No 1-2/3-4 Shift Solenoid valve DTC P0753. |
| • | No 1-2/3-4 Shift Solenoid valve DTC P0758. |
| • | No TCC enable solenoid circuit- Electrical DTC P0743. |
| • | No band apply solenoid circuit DTC P1850. |
Condition for Setting the DTC
the TCM detects a continuous open circuit at TCM terminals 52 and 53 for 0.12 seconds
Action Taken When the DTC Sets
| • | The TCM flashes the sport mode lamp 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. |
| • | 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
| • | 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 ignition switch is Off long enough in order to power down the TCM. |
Test Description
The number below refers to the step number on the Diagnostic Table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform Powertrain On Board Diagnostic (OBD) System Check - Automatic Transmission ? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check - Automatic Transmission | |
2 |
Caution: When you are performing service on or near the SIR components or the SIR wiring, you must disable the SIR system. Refer to Disabling the SIR System. Failure to follow the correct procedure could cause air bag deployment, personal injury, or unnecessary SIR system repairs.
Does the test light illuminate? | -- | ||
3 | With the J 35616-200 connected to B+, probe the transmission power relay output circuit (terminals 52 and 53) in the TCM harness connector. Does the test light illuminate? | -- | ||
4 |
Does the test light illuminate? | -- | ||
5 |
Does the test light illuminate? | -- | ||
Use a J 39200 digital multimeter (DMM) in order to test the harness for continuity of the transmission power relay output circuit (terminals 52 and 53) from the TCM harness connector to either the Main Case or Adapter Case harness connector. Is continuity indicated? | -- | |||
7 | Repair the power relay output circuit shorted to B+. Is the action complete? | -- | -- | |
8 | Repair the power relay output circuit shorted to ground. Is the action complete? | -- | -- | |
9 | Repair the open/high resistance power relay output circuit. Is the action complete? | -- | -- | |
10 | Repair the transmission power relay output circuit shorted to ground in the adapter case. Is the action complete? | -- | -- | |
11 | Repair the transmission power relay output circuit shorted to ground in the main case. Is the action complete? | -- | -- | |
12 | Replace the TCM. Refer to Transmission Control Module Replacement . Is the action complete? | -- | -- | |
13 |
Did DTC P1800 reset? | -- | System OK |
