DTC P1860 TCC PWM Solenoid Circuit Electrical. Cadillac Concours 1996

For 1990-2009 cars
Automatic Transmission Components
Brake Switch, Solenoids, and VSS
Handling ESD Sensitive Parts Notice
OBD II Symbol Description Notice

### System Operation

Ignition voltage is provided to the Torque Converter Clutch Solenoid Valve (TCC Sol. Valve). The PCM controls the ON and OFF time of the solenoid by providing a ground through output driver module (ODM) B. The PCM uses a pulse width modulation (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.

When 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 is set.

• | The engine has been running for 5 seconds.

• | The TCC Sol. Valve duty cycle is between 10% and 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 Torque Converter Clutch.

• | The PCM inhibits 4th gear when the transmission is in hot mode.

### Conditions for Clearing the MIL/DTC

• | The PCM turns OFF the MIL after three consecutive ignition cycles 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 for poor electrical connections at the transmission 20-way connector. Inspect the wiring for poor electrical connections at the 2-way TCC Sol. Valve connector. Look for the following conditions:

- | A bent terminal

- | A backed out terminal

- | A damaged terminal

- | Poor terminal tension

- | A chafed wire

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

• | When diagnosing for an intermittent short or open condition, 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 chart.

1. This Step ensures that you performed the Powertrain On-Board Diagnostic System Check.

2. This Step ensures that you verified the transmission fluid and that the fluid is at the proper level.

3. 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. Use the J 35616-A Connector Test Adapter Kit, in order to avoid damaging the terminals.

4. This Step uses the scan tool in order to cycle the TCC Sol. Valve ON and OFF.

5. This Step verifies that the test lamp is always OFF.

6. This Step verifies that the test lamp is always ON, and never turned OFF, or does not pulse.

7. This Step verifies that the TCC PWM Sol. Valve is within resistance specifications.

8. This Step inspects and repairs circuit 420 and circuit 422 of the Automatic Transmission Wiring Harness. If you find an open in the transmission harness, you must replace the harness.

9. This Step inspects circuit 422 of the Automatic Transmission Wiring Harness. If you find a short to ground in the transmission harness, you must replace the harness.

10. This Step replaces the TCC PWM Sol. Valve after you have verified all the related circuitry.

11. This Step replaces the PCM after you have verified all the related circuitry and components.

#### DTC P1860 Torque Converter Clutch (PWM) Solenoid Valve Electrical

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to A Powertrain On Board Diagnostic (OBD) System Check
2 | Have you performed the transmission fluid checking procedure? | -- | Go to Step 3 | Go to Transmission Fluid Check

3

1. Install the scan tool (tech 1) .
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.
4. Disconnect the transmission 20-way connector.
5. Connect a test light from terminal U to terminal T of the Engine Wiring Harness.

Is the test lamp ON?

--

Go to Step 4

Go to Step 5

4 | Inspect circuit 422 for a short to ground. Refer to Electrical Diagnosis, Section 8. Is the repair complete? | -- | Go to Step 16 | Go to Step 15

5

1. Enter A/T Outputs, then enter TCC Enable.
2. Cycle the TCC Sol. Valve ON and OFF three times.
3. The test lamp should pulse.

Does the test lamp cycle ON and OFF as commanded?

--

Go to Step 10

Go to Step 6

6 | Is the test lamp always OFF? | -- | Go to Step 7 | Go to Step 8
7 | Inspect circuit 839 and circuit 422 of the Engine Wiring Harness for an open. Refer to Electrical Diagnosis, Section 8. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 15
8 | Is the test lamp always ON? | -- | Go to Step 9 | --
9 | Inspect circuit 422 for a short to power. Refer to Electrical Diagnosis, Section 8. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 15

10

1. Install the J 39775 Jumper Harness to the Automatic Transmission Wiring Harness 20-way connector.
2. Connect an ohmmeter from terminal U to terminal T.

Does the ohmmeter display a value within the specified range?

10-15ohms

Go to Step 12

Go to Step 11

11 | Inspect circuits 420 and 422 of the Automatic Transmission Wiring Harness for an open. Refer to Electrical Diagnosis, Section 8. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 14
12 | Connect an ohmmeter from terminal T to the transmission case. Is the ohmmeter display less than the specified value? | 10ohms | -- | Go to Step 13
13 | Inspect circuit 422 of the Automatic Transmission Wiring Harness for a short to ground. Refer to Electrical Diagnosis, Section 8. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 14
14 | Replace the TCC PWM Sol. Valve. Refer to TCC PWM Sol. Valve Replacement in On-Vehicle Service. Is the replacement complete? | -- | Go to Step 16 | --
15 | Replace the PCM. Refer to PCM Replacement/Programming Section 6. Is the replacement complete? | -- | Go to Step 16 | --

16

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:

3.1. | Road test the vehicle with the gear select lever in D4.

3.2. | Increase the vehicle speed until TCC Enable turns ON.

3.3. | Ensure that the TCC duty cycle is 10-85% for more than 5 seconds.

4. Select Specific DTC. Enter DTC P1860.

Has the test run and passed?

--

System OK

Begin the diagnosis again. Go to Step 1