Circuit Description
Ignition voltage is provided to the torque converter clutch pulse width modulation (TCC PWM) solenoid valve . The 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 Running the DTC
| • | No ODM DTC P1650. |
| • | The engine run time is greater than 5 seconds. |
| • | The TCC PWM solenoid valve duty cycle is less than 10% or greater than 85%. |
Conditions for Setting the DTC
The PCM detects an open, a short to ground, or a short to power on the TCC PWM solenoid 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. |
| • | The PCM stores DTC P1860 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 PCM history. |
| • | 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 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, the TCC PWM solenoid valve 2-way connector, and all other circuit connecting points for the following conditions: |
| - | A backed out terminal |
| - | A damaged terminal |
| - | Reduced 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 solenoid valve ON and OFF.
-
This step verifies that the TCC PWM solenoid valve is within resistance specifications.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||||||||
2 |
Important: Before clearing the DTCs, 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. Is DTC P0753 or P0758 set? | -- | ||||||||
Refer to Wiring Repairs in Wiring Systems. Was the condition found? | -- | |||||||||
4 |
Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics in Wiring Systems, for complete circuit distribution. Inspect circuit 839 of the engine wiring harness for a short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Was the condition found? | -- | ||||||||
Refer to General Electrical Diagnosis in Wiring Systems. Was a condition found? | -- | -- | ||||||||
6 |
Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics in Wiring Systems, for complete circuit distribution. Inspect circuit 839 of the engine wiring harness for an open. Refer to General Electrical Diagnosis in Wiring Systems. Was the condition found? | -- | -- | |||||||
7 |
Is the test lamp ON? | -- | ||||||||
8 | Inspect circuit 422 of the engine wiring harness for a short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Was the condition found? | -- | ||||||||
9 | Using the scan tool, cycle the TCC PWM solenoid valve ON and OFF three times (the test lamp should pulse). Does the test lamp cycle ON and OFF as commanded? | -- | ||||||||
Is the test lamp always OFF? | -- | |||||||||
11 | Inspect circuit 422 and circuit 839 of the engine wiring harness for an open. Refer to General Electrical Diagnosis in Wiring Systems. Was the condition found? | -- | ||||||||
12 | Inspect circuit 422 of the engine wiring harness for a short to power. Refer to General Electrical Diagnosis in Wiring Systems. Was the condition found? | -- | ||||||||
13 |
Is the resistance value within the specified range? | 10-15 ohms | ||||||||
14 | Is the resistance greater than the specified value? | 15 ohms | ||||||||
15 |
Refer to General Electrical Diagnosis in Wiring Systems. Was a condition found? | -- | ||||||||
16 | Measure the resistance from terminal T to the transmission case. Is the resistance less than the specified value? | 100 ohms | Go to Diagnostic Aids | |||||||
17 | Inspect circuit 418 of the automatic transmission wiring harness for a short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Was the condition found? | -- | ||||||||
18 | Repair the wiring as necessary. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |||||||
19 | Replace the automatic transmission wiring harness. Refer to Unit Repair. Is the replacement complete? | -- | -- | |||||||
20 | Replace the TCC PWM solenoid valve. Refer to Unit Repair. Is the replacement complete? | -- | -- | |||||||
21 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls. Is the replacement complete? | -- | -- | |||||||
22 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | System OK |
