Circuit Description
The torque converter clutch (TCC) release switch is part of the automatic transmission fluid pressure (TFP) manual valve position switch. The TFP manual valve position switch is attached to the control valve body. The TCC release switch is normally-closed.
The switch signals the PCM that the TCC is released. This is accomplished by torque converter release fluid pressure acting on the switch contact, thus opening the switch. When the voltage is high on the circuit, the PCM recognizes that the TCC is no longer engaged.
When the PCM determines that the TCC release switch is open, indicating that the TCC is not applied, and the TCC slip speed indicates that the TCC is applied, then DTC P1887 sets. DTC P1887 is a type B DTC.
Conditions for Running the DTC
| • | No AT ISS DTCs P0716 or P0717. |
| • | No TCC DTCs P0741 or P0742. |
| • | The engine run time is greater than 5 seconds. |
| • | The TFP manual valve position switch indicates D4 range. |
| • | The engine torque is greater than 41 N·m (30 lb ft). |
| • | The TCC is commanded ON. |
| • | The TCC slip speed is -20 to +40 RPM. |
Conditions for Setting the DTC
The TCC release switch is open, release fluid pressure present, for 6 seconds, twice during the same trip.
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met. |
| • | The PCM inhibits TCC engagement. |
| • | The PCM freezes transmission adapt functions. |
| • | The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records. |
| • | The PCM stores DTC P1887 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes. |
| • | A scan tool can clear the MIL/DTC. |
| • | The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring. |
| • | The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM. |
Diagnostic Aids
Ensure the wiring harness is not stretched too tightly or other components are pressing on the connector body. Also, inspect for proper clearance to any other components and wiring. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests the ability of the PCM to recognize a grounded circuit.
-
This step tests for a mechanical or hydraulic condition.
Step | Action | Value(s) | Yes | No | ||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls | ||||||||||||||||||||||||||||||||||||
2 |
Important: Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the PCM. Does the scan tool indicate TCC release pressure is present? | -- | Go to Step 3 | Go to Step 6 | ||||||||||||||||||||||||||||||||||||
Refer to Automatic Transmission Inline Harness Connector End View . Does the scan tool indicate TCC release pressure is present? | -- | Go to Step 4 | Go to Step 5 | |||||||||||||||||||||||||||||||||||||
4 | Test the signal circuit (CKT 657) of the TCC release switch for an open between the PCM connector C2 and the AT inline 20-way connector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 10 | ||||||||||||||||||||||||||||||||||||
5 | Test the signal circuit (CKT 1804) of the TCC release switch for an open between the AT inline 20-way connector and the TFP manual valve position switch. Refer to Circuit Testing in Wiring Systems. Did you find the condition? | -- | Go to Step 8 | Go to Step 9 | ||||||||||||||||||||||||||||||||||||
6 |
With the TCC applied and slip speed less than 40 RPM does the scan tool indicate TCC release pressure is present? | -- | Go to Step 7 | Go to Intermittent Conditions in Engine Controls | ||||||||||||||||||||||||||||||||||||
Refer to Transmission Overhaul in Transmission Unit Repair Manual. Did you complete the repair? | -- | Go to Step 11 | -- | |||||||||||||||||||||||||||||||||||||
8 | Replace the automatic transmission wiring harness. Refer to Transmission Overhaul in Transmission Unit Repair Manual. Did you complete the repair? | -- | Go to Step 11 | -- | ||||||||||||||||||||||||||||||||||||
9 | Replace the TFP manual valve position switch. Refer to Pressure Switch Assembly Replacement. Did you complete the repair? | -- | Go to Step 11 | -- | ||||||||||||||||||||||||||||||||||||
10 | Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls. Did you complete the repair? | -- | Go to Step 11 | -- | ||||||||||||||||||||||||||||||||||||
11 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | System OK | Go to Step 1 |
