Circuit Description
The Transmission Control Module (TCM) provides voltage to the pressure control solenoid, the shift solenoids and the torque converter clutch pulse width modulated solenoid through two separate solid state devices called High Side Drivers, called HSD1 and HSD2. HSD1 provides electrical power to the pressure control solenoid. HSD2 provides power to the shift solenoids and the torque converter clutch solenoid. A normal function of the TCM is to run tests on each driver to ensure that it is functioning properly.
When the TCM detects a short to voltage on HSD2 driver circuit, then DTC P1834 sets, which is a type 'B' DTC.
Conditions for Running the DTC
| • | Ignition voltage is between 8.0 and 18.0 volts. |
| • | Engine is running between 450 and 6,800 RPM for at least 5 seconds. |
Conditions for Setting the DTC
The TCM detects a short to power on the HSD2 circuit when the HSD2 is commanded on.
Action Taken When the DTC Sets
| • | The TCM requests the Powertrain Interface Module (PIM) to illuminate the Check Powertrain Malfunction Indicator Lamp (MIL) in the instrument cluster during the second consecutive drive trip in which the 'Conditions for Setting the DTC' are met. |
| • | The TCM turns off power to all solenoids. |
| • | The transmission will operate in fifth gear if the vehicle has successfully completed a 1-2 upshift in the current ignition cycle. If the vehicle has not completed a 1-2 upshift in the current ignition cycle, the transmission will operate in fourth gear. |
| • | At the time of the first failure, the TCM records the operating conditions when the 'Conditions for Setting the DTC' are met. The TCM stores this information as a failure record. |
| • | At the time of the second failure, the TCM records the operating conditions when the 'Conditions for Setting the DTC' are met. The ECM stores this information as a freeze frame. |
| • | The TCM freezes the transmission adaptive learning function. |
| • | The TCM stores DTC P1834 into TCM history. |
| • | The TCM also turns off the pressure control solenoid (causing maximum line pressure). |
| • | Torque management is inhibited. |
Conditions for Clearing the MIL/DTC
| • | The ECM turns off the MIL after the sixth consecutive drive trip in which the TCM does not send a MIL illumination request. |
| • | Tech 2 can clear the DTC. |
| • | The TCM clears the DTC from its memory (history DTC) if the vehicle completes 40 warm-up cycles without a non-emission related DTC occurring. |
| • | The TCM cancels the DTC default actions when the ignition is off long enough to power down the TCM. |
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Automatic Transmission Controls Schematics For information on testing wiring faults, refer to Wiring Systems. | ||||||||||
1 | Has the Diagnostic System Check - Automatic Transmission been completed? | -- | Go to Step 2 | |||||||
2 |
Did DTC P1834 reset? | -- | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections | ||||||
3 |
Is the voltage greater than the specified value? | More than 6.4 Volts | Go to Step 4 | Go to Step 5 | ||||||
4 | Repair the short to voltage on the solenoid supply voltage circuit. Is the action complete? | -- | Go to Step 6 | -- | ||||||
5 | Replace TCM. Refer to Transmission Control Module Replacement. Is the replacement complete? | -- | Go to Step 6 | -- | ||||||
6 |
Has the test run and passed? | -- | System OK | Go to Step 2 | ||||||
When all diagnosis and repairs are completed, clear all DTCs and verify correct operation. | ||||||||||
