For 1990-2009 cars
Automatic Transmission Components
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

### 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.

DTC P1860 sets anytime the received voltage is outside of the calibration limits. DTC P1860 is a type A DTC .

### Conditions for Setting the DTC

• | The system voltage is 9-16 volts.

• | The engine speed is greater than 500 RPM for 5 seconds, and not in fuel shut off.

• | The ignition is ON.

• | The PCM commands the solenoid to greater than 90% duty cycle and voltage remains low (0.0 volts).

• | The PCM commands the solenoid to less than 10% duty cycle and voltage remains high (B+).

• | All 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

• | The PCM disables shift adapts.

### 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 for poor electrical connections at the PCM. Inspect the wiring at the transmission 20-way connector. Inspect the wiring at the 2-way TCC connector. Look for the following problems:

- | A bent terminal

- | A backed out terminal

- | A damaged terminal

- | Poor terminal tension

- | A chafed wire

- | A broken wire inside the insulation

• | When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.

• | Ensure that the transmission fluid is at the proper level.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. This step isolates the engine harness from the transmission harness. Use a test lamp in order to verify the circuitry.

2. This step verifies that circuit 418 is not open or shorted to power.

3. This step verifies that the TCC PWM solenoid is not shorted across its windings or increased its resistance.

4. 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.

#### DTC P1860 Torque Converter Clutch (PWM) Solenoid Circuit -- Electrical

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls
2 |

1. Install the Scan Tool .
2. With the engine OFF, turn the ignition switch to the RUN position.

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.

3. Record the DTC Freeze Frame and Failure Records, then clear the DTCs.

Are DTCs P0753 and P0758 set?

--

Go to Step 3

Go to Step 6

3 |

1. Remove the TCC fuse 7D.
2. Inspect the fuse for an open.

Refer to General Electrical Diagnosis in Wiring Systems.

Did you find and correct a condition?

--

Go to Step 4

Go to Step 5

4 | Repair the short to ground in circuit 339 (PNK)/839 (RED). Refer to Wiring Repairs in Wiring Systems. Did you find and correct a condition? | -- | Go to Step 18 | --
5 | Repair the open in circuit 339 (PNK)/839 (RED). Refer to Wiring Repairs in Wiring Systems. Did you find and correct a condition? | -- | Go to Step 18 | --
6 |

1. Turn the ignition switch OFF.
2. Disconnect the transmission 20-way connector.
3. Connect the J 39775 Jumper Harness on the engine harness connector.
4. Connect a test lamp from terminal E to terminal T of the jumper.
5. With the engine OFF, turn the ignition ON.
6. Additional DTCs will set.

Is the test lamp ON?

--

Go to Step 7

Go to Step 8

7 | Inspect circuit 418 (BRN) of the engine harness for a short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Did you find and correct a condition? | -- | Go to Step 18 | Go to Step 16
8 |

1. Select A/T Outputs, TCC PWM Solenoid.
2. Cycle the TCC PWM solenoid ON and OFF three times.

Important: When the TCC PWM solenoid is ON, the test lamp will be brilliant. When the TCC PWM solenoid is OFF, the test lamp will pulsate.

Does the solenoid cycle ON and OFF as commanded?

--

Go to Step 10

Go to Step 9

9 | Inspect circuit 418 (BRN) of the engine harness for an open or a short to power. Refer to General Electrical Diagnosis in Wiring Systems. Did you find and correct a condition? | -- | Go to Step 18 | Go to Step 16
10 |

1. Turn the ignition switch OFF.
2. Disconnect the J 39775 Jumper Harness from the engine harness.
3. Connect the J 39775 Jumper Harness to the transmission 20-way connector.

Refer to Automatic Transmission Inline Harness Connector End View .

4. Connect a J 39200 Digital Multimeter (DMM), set to measure ohms, from terminal E to terminal T of the J 39775 Jumper Harness.

Is the measured resistance within the specified range?

10-12 ohms at 20°C (68°F)

13-15 ohms at 88°C (190°F)

Go to Step 13

Go to Step 11

11 | Is the resistance greater than the specified value? | 100 ohms | Go to Step 12 | Go to Step 13
12 |

1. Inspect automatic transmission wiring harness circuit 839 (RED) for an open or poor connection.
2. Inspect circuit 418 (TAN) for an open or poor connection.

Refer to General Electrical Diagnosis in Wiring Systems.

Did you find a condition?

--

Go to Step 17

Go to Step 15

13 | Connect a J 39200 DMM from terminal T of the J 39775 Jumper Harness to ground. Is the measured resistance less than the specified value? | 100 ohms | Go to Step 14 | Go to Step 15
14 | Inspect automatic transmission wiring harness circuit 418 (TAN) for a short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Did you find and correct a condition? | -- | Go to Step 17 | --
15 | Replace the TCC PWM Sol. Valve. Refer to Torque Converter Clutch Pulse Width Modulation Solenoid Replacement . Is the replacement complete? | -- | Go to Step 18 | --
16 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls. Is the replacement complete? | -- | Go to Step 18 | --
17 | Replace the Automatic Transmission Wiring Harness. Refer to Solenoids and Wiring Harness Replacement . Is the replacement complete? | -- | Go to Step 18 | --
18 | In order to verify your repair, perform the following procedure:

1. Select DTC.
2. Select Clear Info.
3. Operate the vehicle under the following conditions:

• | The system voltage is 9-16 volts.

• | The ignition switch is ON.

• | The engine speed is more than 500 RPM for 5 seconds.

• | The vehicle is not in fuel shut off.

• | The PCM commands the TCC PWM duty cycle to less than 10%, and the circuit 418 voltage decreases to 0 volts.

• | The PCM commands the TCC PWM duty cycle to greater than 90%, and the circuit 418 voltage increases to B+.

• | All these conditions are true for 5 seconds.

4. Select Specific DTC.
5. Enter DTC P1860.

Has the test run and passed?

--

System OK

Go to Step 1