Circuit Description
Ignition voltage is provided to the Torque Converter Clutch Pulse Width Modulation Solenoid Valve (TCC PWM Sol. Valve). The Powertrain Control Module (PCM) controls the ON and OFF time of the solenoid by providing a ground through the Output Driver Module (ODM) B. The PCM uses a PWM duty cycle, in order to control application and release of the TCC. When the solenoid is commanded OFF, the PCM senses high volts. When the solenoid is commanded ON, the PCM senses low volts.
If the PCM detects voltage limits that do not meet the calibration, then DTC P1860 sets. DTC P1860 is a Type A DTC.
Conditions for Setting the DTC
| • | No ODM DTC P1650. |
| • | The engine run time is greater than 5 seconds. |
| • | The TCC PWM Sol. Valve duty cycle is less than 10% or greater than 85%. |
| • | The PCM detects an open, a short to ground, or a short to power on the TCC PWM Sol. Valve circuit within 5 seconds. |
Action Taken When the DTC Sets
| • | The PCM illuminates the Malfunction Indicator Lamp (MIL). |
| • | SERVICE ENGINE SOON, SERVICE TRANSMISSION displays on the Driver Information Center (DIC). |
| • | The PCM inhibits TCC engagement. |
| • | The PCM inhibits 4th gear when the transmission is in hot mode. |
| • | DTC P1860 is stored in the PCM history. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL after three consecutive trips without a failure reported. |
| • | A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported. |
| • | The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM. |
Diagnostic Aids
| • | Inspect the wiring at the PCM, the transmission 20-way connector, the TCC PWM Sol. Valve 2-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 |
| • | Ensure that the transmission fluid is at the proper level. |
| • | 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 verifies power to terminal U of the engine wiring harness. If the test lamp lights, inspect circuit 422 for a short to ground.
-
This step uses the Scan Tool in order to cycle the TCC PWM Sol. Valve ON and OFF.
-
This step verifies that the TCC PWM Sol. Valve is within resistance specifications.
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 | Have you performed the transmission fluid checking procedure? | -- | Go to Transmission Fluid Check | |||||||
Important: Before clearing the DTC(s), use the Scan Tool in order to record the Freeze Frame and Failure Records for reference. Using the Clear Info function will erase the stored Freeze Frame and Failure Records from the PCM. Is the test lamp ON? | -- | |||||||||
4 | Inspect circuit 422 for a short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Did you find and correct the condition? | -- | ||||||||
Using the Scan Tool cycle the TCC PWM Sol. Valve ON and OFF three times (the test lamp should pulse). Does the test lamp cycle ON and OFF as commanded? | -- | |||||||||
6 | Is the test lamp always OFF? | -- | ||||||||
7 | Inspect circuit 839 and circuit 422 for an open. Refer to General Electrical Diagnosis in Wiring Systems. Did you find and correct the condition? | -- | ||||||||
8 | Is the test lamp always ON? | -- | -- | |||||||
9 | Inspect circuit 422 for a short to power. Refer to General Electrical Diagnosis in Wiring Systems. Did you find and correct the condition? | -- | ||||||||
Is the resistance value within the specified range? | 10-15 ohms | |||||||||
11 | Is the resistance greater than the specified value? | 15 ohms | ||||||||
12 |
Refer to General Electrical Diagnosis in Wiring Systems. Did you find the condition? | -- | ||||||||
13 | Measure the resistance from terminal T to the transmission case. Is the resistance less than the specified value? | 100 ohms | Go to Diagnostic Aids | |||||||
14 | Inspect circuit 418 of the automatic transmission wiring harness for a short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Did you find the condition? | -- | ||||||||
15 | Replace the automatic transmission wiring harness. Refer to Transmission Overhaul in the 4T80-E Section of the Transmission Unit Repair Manual. Is the replacement complete? | -- | -- | |||||||
16 | Replace the TCC PWM Sol. Valve. Refer to Transmission Overhaul in the 4T80-E Section of the Transmission Unit Repair Manual. Is the replacement complete? | -- | -- | |||||||
17 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls. Is the replacement complete? | -- | -- | |||||||
18 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
