Circuit Description
The Torque Converter Clutch Pulse Width Modulation Solenoid Valve (TCC PWM Sol. Valve) controls the fluid acting on the converter clutch valve. The converter clutch valve controls the application and the release of the TCC. The PCM controls the TCC PWM Sol. Valve by varying its duty cycle (ON/OFF time) from 0-100%, thus modulating the feed pressure to the converter clutch regulator valve. At 0% duty cycle, the torque converter clutch applies at maximum capacity. At 100% duty cycle the clutch applies at minimum capacity.
Ignition voltage is applied through circuit 1039 to the TCC PWM solenoid. The Output Driver Module (ODM), within the PCM provides the ground path for the circuit.
When the PCM detects a continuous open or short to ground in the TCC PWM circuit then DTC P1860 sets. DTC P1860 is a type A DTC.
Conditions for Setting the DTC
| • | System voltage is 10-16 volts. |
| • | The engine speed is more than 500 RPM. |
| • | Not in fuel shut off. |
| • | The PCM commands the solenoid below 10% and above 90% duty cycle and the voltage on circuit 418 is outside the calibrated limit. |
All of the above conditions are met for 5 seconds.
Action Taken When the DTC Sets
| • | The PCM illuminates the Malfunction Indicator Lamp (MIL). |
| • | The PCM inhibits TCC operation. |
| • | The PCM inhibits 4th gear if the transmission is in the hot mode. |
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 connector, TCC PWM solenoid connector and all other circuit connecting points for the following conditions:
- When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.
- Ensure that the transmission fluid is at the proper level.
| • | 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 |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step isolates the engine harness from the transmission harness.
-
This step verifies that engine harness circuit 418 is not open or shorted to power.
-
This step verifies that the TCC PWM solenoid is not shorted across its windings or open, or the transmission harness is not shorted or open.
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 for reference. The Clear Info function will erase the stored Freeze Frame and Failure Records from the PCM. Did either reading pulsate No/Yes/No? | -- | Go to Diagnostic Aids | |||||||||||||
Is the test lamp OFF? | -- | |||||||||||||||
4 | Inspect engine harness circuit 418 for an open. Refer to General Electrical Diagnosis . Was a condition found and corrected? | -- | ||||||||||||||
Important: On the 4T60-E transmission, when the scan tool is used to command the TCC PWM (Control) Solenoid ON, the display indicates 99% duty cycle. However, the solenoid will be de-energized (test lamp off). When commanded OFF, the display indicates 0% duty cycle, but the solenoid will be energized (test lamp on). Does the solenoid cycle ON and OFF as commanded? | -- | |||||||||||||||
6 | Inspect engine harness circuit 418 for a short to ground. Refer to General Electrical Diagnosis . Was a condition found and corrected? | -- | ||||||||||||||
7 | Inspect engine harness circuit 418 for a short to power. Refer to General Electrical Diagnosis . Was a condition found and corrected? | -- | ||||||||||||||
Is the measured resistance within the specified range? | 10 ohms to 15 ohms | |||||||||||||||
9 | Is the resistance greater than the specified value? | 15 ohms | ||||||||||||||
10 | Inspect the RED wire circuit 839 and the BLK wire circuit 418, of the transmission harness, for an open. Refer to General Electrical Diagnosis . Was a condition found? | -- | ||||||||||||||
11 | Replace the Automatic Transmission Wiring Harness. Refer to Solenoids and Wiring Harness Replacement . Is the replacement complete? | -- | -- | |||||||||||||
12 | Connect a J 39200 Digital Multimeter (DMM), from terminal C of the jumper, to ground. Is the measured resistance less than the specified value? | 100 ohms | ||||||||||||||
13 | Inspect the BLK wire circuit 418 of the transmission harness for a short to ground. Refer to General Electrical Diagnosis . Was a condition found? | -- | -- | |||||||||||||
14 | Replace the Automatic Transmission Wiring Harness. Refer to Solenoids and Wiring Harness Replacement . Is the replacement complete? | -- | -- | |||||||||||||
15 | Replace the TCC PWM Sol. Valve. Refer to Torque Converter Clutch Pulse Width Modulation Solenoid Replacement . Is the replacement complete? | -- | -- | |||||||||||||
16 | Inspect PCM connector C2 (Clear) for bent, damaged or backed out connector pins. Was a condition found and corrected? | -- | ||||||||||||||
17 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the replacement complete? | -- | -- | |||||||||||||
18 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
