Circuit Description
The transmission control module (TCM) provides voltage to shift solenoid 1, 2, and 3 (SS1, SS2, and SS3) and pressure control solenoid 2 (PCS2) through a separate solid-state device called high side driver 2 (HSD2). HSD2 is continuously ON during normal operation, except during a brief circuit test. The TCM regulates control current to the solenoids by switching the appropriate low side driver ON and OFF.
DTC P2671 is a type A DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P2671 Actuator Supply Voltage 2 High
Conditions for Running the DTC
| • | The components are powered and ignition voltage is greater than 9.0 volts and less than 18 volts. |
| • | HSD2 is commanded ON. |
Conditions for Setting the DTC
DTC P2671 sets when the TCM detects greater than 6.0 volts at the HSD2 terminal prior to commanding HSD2 ON.
Action Taken When the DTC Sets
| • | The TCM illuminates the malfunction indicator lamp (MIL). |
| • | If the failure occurs while in a forward range, a shift to 1st, 3rd or 5th range is made. |
| • | While diagnostic response is active, if the shift selector is moved to NEUTRAL, the transmission will shift to NEUTRAL. If the shift selector is moved to REVERSE, the transmission will shift to REVERSE. If the shift selector is moved to a forward range or to REVERSE and the transmission is compromised by overspeeding or direction change, the transmission will shift to NEUTRAL. |
| • | DTC P2671 is stored in TCM history. |
| • | Main modulation (MAIN MOD) is inhibited. |
| • | The TCM freezes shift adapts. |
| • | The TCM inhibits torque converter clutch (TCC) engagement. |
Conditions for Clearing the MIL/DTC
A scan tool can clear the code from TCM history. The TCM automatically clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
| • | Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions: |
| - | A bent terminal |
| - | A backed-out terminal |
| - | A damaged terminal |
| - | Poor terminal tension |
| - | A chafed wire |
| - | A broken wire inside the insulation |
| • | When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change. |
| • | You may have to drive the vehicle in order to experience a condition. |
Step | Action | Value | Yes | No |
|---|---|---|---|---|
Schematic Reference: Automatic Transmission Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
2 |
Important: Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function will erase the data. Is voltage within the specified value? | 9-18 V | Go to Step 3 | Go to DTC P0562 for low voltage or DTC P0563 for high voltage |
3 |
Is the voltage greater than the specified value? | 6 V | Go to Step 4 | Go to Step 8 |
4 |
Is the voltage greater than the specified value? | 6 V | Go to Step 6 | Go to Step 5 |
5 |
Is the voltage greater than the specified value? | 6 V | Go to Step 7 | Go to Diagnostic Aids |
6 | Test the HSD2 circuit between the TCM and AT inline 20-way connector for a short to voltage. Refer to Testing for a Short to Voltage . Did you find and correct the condition? | -- | Go to Step 10 | -- |
7 | Replace the AT internal wiring harness. Refer to Wiring Harness Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- |
8 |
Important: In most cases, the TCM is not at fault. Investigate thoroughly before replacing the TCM. Replace the TCM. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement? | -- | Go to Step 10 | -- |
9 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | Go to Step 10 | Go to Step 2 |
10 | With the scan tool, observe the stored information, capture info and DTC info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
