Circuit Description
The torque converter clutch (TCC) release switch is part of the automatic transmission fluid pressure manual valve position switch (TFP Valve Position Switch). The TFP Valve Position Switch is mounted to the transmission valve body. The TCC release switch is normally-closed.
The switch signals the powertrain control module (PCM) that the TCC is released. This is accomplished by torque converter release fluid pressure acting on the switch contact which opens circuit 657/1804. When the voltage is high on the circuit, the PCM recognizes that the TCC is no longer engaged.
If 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 Setting the DTC
DTC P1887 sets during the second consecutive trip in which the following conditions occur:
| • | No A/T ISS sensor DTCs P0716 or P0717. |
| • | No TCC PWM Solenoid Valve DTCs P0741 or P0742. |
| • | No TFP Valve Position Switch DTC P1810. |
| • | The engine speed is greater than 500 RPM for 5 seconds and not in fuel shut off. |
| • | The transmission range switch is in D4. |
| • | The TCC is commanded ON. |
| • | The TCC pressure is 138-827 kPa (20-120 psi). |
| • | The TCC slip speed is -20 to +40 RPM on 3.8L vehicles and -20 to +60 RPM on 3.5L vehicles. |
| • | Engine torque is 45-407 N·m (33-300 lb ft) on 3.8L vehicles and 41-339 N·m (30-250 lb ft) on 3.5L vehicles. |
| • | The TCC release pressure switch is open (indicating release pressure is present). |
| • | All of the above conditions are met twice in the same ignition cycle for 6 seconds on 3.8L vehicles and 8 seconds on 3.5L vehicles. |
Action Taken When the DTC Sets
| • | The PCM illuminates the Malfunction Indicator Lamp (MIL). |
| • | The PCM inhibits TCC. |
| • | The PCM inhibits 4th gear if the transmission is in Hot Mode. |
| • | The PCM freezes shift adapts. |
| • | The PCM stores DTC P1887 in PCM history. |
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 clears the DTC from the PCM history. |
| • | The PCM clears the DTC from the PCM history if the vehicle completes 40 consecutive warm-up cycles without an emission related diagnostic fault occurring. |
| • | The PCM cancels the DTC default actions when the fault no longer exists and the ignition switch is OFF long enough in order to power down the PCM. |
Diagnostic Aids
| • | Inspect the wiring at the PCM, the transmission 20-way connector and all other circuit connecting points 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 |
| - | Moisture intrusion |
| - | Corrosion |
| • | When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests the PCMs ability to recognize an open circuit.
-
Because of the harsh conditions inside the transmission, repairing the A/T Wiring Harness is not acceptable. You must replace the A/T Wiring Harness.
Step | Action | Value(s) | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls | |||||
2 |
Important: Before clearing the DTCs, 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 TCC release pressure present? | -- | Go to Diagnostic Aids | |||||
Is TCC Release Pressure present? | -- | |||||||
4 | Inspect engine wiring harness circuit 657 (YEL) for an open. Refer to General Electrical Diagnosis in Wiring Systems. Did you find and correct the condition? | -- | ||||||
5 |
Refer to the Connector End View . Is the resistance less than the specified value? | 50 ohms | Go to Diagnostic Aids | |||||
6 | Inspect automatic transmission wiring harness circuit 1804 (WHT) for an open. Refer to General Electrical Diagnosis in Wiring Systems. Did you find the condition? | -- | ||||||
7 | Replace the TFP Val. Position Sw. Refer to Solenoids and Wiring Harness Replacement . Is the replacement complete? | -- | -- | |||||
8 | Inspect PCM connector C1 (BLU) for bent, damaged or backed out connector pins. Was the condition found and corrected? | -- | ||||||
9 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls. Is the replacement complete? | -- | -- | |||||
Replace the automatic transmission wiring harness. Refer to Solenoids and Wiring Harness Replacement . Is the replacement complete? | -- | -- | ||||||
11 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | System OK |
