For 1990-2009 cars
Master Electrical Component List
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice

### Circuit Description

The transmission control module (TCM) provides voltage to the pressure control solenoid, the shift solenoids, the band apply solenoid, and the TCC enable solenoid through an internal power control relay. A normal function of the TCM is to run tests on the power control relay to ensure that it is functioning properly. The power control relay has two output terminals on the TCM. The pressure control solenoid signal circuit receives voltage from TCM terminal 52. The other solenoids receive voltage from TCM terminal 53. TCM terminals 52 and 53 are connected inside the TCM.

When the TCM detects a short to ground or short to B+ on the power control relay circuit, then DTC P1625 sets. DTC P1625 is a type B DTC.

### Condition for Running the DTC

The ignition is ON.

### Condition for Setting the DTC

The TCM detects a short to ground or short to B+ on the power control relay circuit.

### Action Taken When the DTC Sets

• | The TCM flashes the sport mode lamp and sends a MIL request to the ECM on the second consecutive drive trip that the diagnostic runs and fails. The ECM then illuminates the MIL.

• | The ECM records the operating conditions in the Freeze Frame at the time of the MIL request from the TCM.

• | The transmission operates in the default mode (maximum line pressure, command 4th gear, inhibit TCC, freeze shift adapts).

### Conditions For Clearing the MIL/DTC

• | The ECM turns off the MIL after three consecutive drive trips during which the TCM sends no MIL request.

• | A History DTC clears after forty consecutive warm-up cycles, if no failures are present by this diagnostic or any other emission related diagnostic.

• | The scan tool clears the MIL/DTC.

• | The TCM cancels the DTC default mode actions when the ignition switch is Off long enough in order to power down the TCM.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform Powertrain On Board Diagnostic (OBD) System Check - Automatic Transmission ? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check - Automatic Transmission
2 |

1. Install the Scan Tool .
2. Turn ON the ignition with the engine OFF.

Important: Record the Failure Records before clearing the DTCs. Using the Clear Info function erases the Failure Records from the ECM and the TCM.

3. Record the DTC Freeze Frame and Failure Records.
4. Clear the DTC.
5. Turn OFF the ignition for at least 30 seconds.
6. Turn ON the ignition with the engine OFF.

Did DTC P1625 reset?

--

Go to Step 3

Go to Intermittent Conditions in Engine Controls

3 |

1. Turn OFF the ignition.
2. Disconnect the transmission main case 7-way harness connector.
3. Turn ON the ignition with the engine OFF.
4. Clear the DTC.
5. Turn OFF the ignition for at least 30 seconds.
6. Turn ON the ignition with the engine OFF. Other DTCs will set.

Did DTC P1625 reset?

--

Go to Step 4

Go to Step 6

4 |

1. Turn OFF the ignition.
2. Disconnect the transmission adapter case 4-way harness connector.
3. Turn ON the ignition with the engine OFF.
4. Clear the DTC.
5. Turn OFF the ignition for at least 30 seconds.
6. Turn ON the ignition with the engine OFF. Other DTCs will set.

Did DTC P1625 reset?

--

Go to Step 5

Go to Step 8

5 | Caution: When you are performing service on or near the SIR components or the SIR wiring, you must disable the SIR system. Refer to Disabling the SIR System. Failure to follow the correct procedure could cause air bag deployment, personal injury, or unnecessary SIR system repairs.

1. Disconnect the TCM.
2. Test the main case solenoid signal circuit (CKTs PF754 and PF954) between the transmission harness connectors and the TCM for the following conditions:

• | A short to ground. Refer to Testing for Short to Ground in Wiring Systems.

• | A short to voltage. Refer to Testing for a Short to Voltage in Wiring Systems.

3. Test the PC solenoid signal circuit (CKT FY740) between the transmission harness connectors and the TCM for the following conditions:

• | A short to ground. Refer to Testing for Short to Ground in Wiring Systems.

• | A short to voltage. Refer to Testing for a Short to Voltage in Wiring Systems.

4. Test the TCC enable solenoid signal circuit (CKT PF854) between the transmission harness connectors and the TCM for the following conditions:

• | A short to ground. Refer to Testing for Short to Ground in Wiring Systems.

• | A short to voltage. Refer to Testing for a Short to Voltage in Wiring Systems.

Did you find and correct a condition?

--

Go to Step 11

Go to Step 10

6 |

1. Turn OFF the ignition.
2. Remove the main case oil pan. Refer to Changing Fluid and Oil Filter .
3. Connect the J 44539 jumper harness to the transmission side of the 7-way connector.
4. Test the solenoid signal circuit in the AT internal wiring harness for a short to ground. Refer to Testing for Short to Ground .

Did you find a condition?

--

Go to Step 12

Go to Step 7

7 |

1. Test the solenoids in the main case for a short to ground. Refer to Testing for Short to Ground in Wiring Systems.
2. Replace the shorted solenoid(s). Refer to Control Valve Body .

Did you find and correct a condition?

--

Go to Step 14

--

8 |

1. Remove the adapter case oil pan.
2. Test the PC solenoid signal circuit from the main case connector to the solenoid connectors for a short to ground. Refer to Testing for Short to Ground in Wiring Systems.
3. Test the TCC enable solenoid signal circuit from the main case connector to the solenoid connectors for a short to ground. Refer to Testing for Short to Ground in Wiring Systems.

Did you find a condition?

--

Go to Step 13

Go to Step 9

9 |

1. Test the solenoids in the adapter case for a short to ground. Refer to Testing for Short to Ground in Wiring Systems.
2. Replace the shorted solenoid(s). Refer to Torque Converter Clutch Solenoid Replacement .

Did you find and correct a condition?

--

Go to Step 14

--

10 | Replace the TCM. Refer to Transmission Control Module Replacement . Is the action complete? | -- | Go to Step 14 | --
11 | Perform the necessary wiring repairs. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 14 | --
12 | Replace the main case AT internal transmission wiring harness. Refer to Control Valve Body . Is the action complete? | -- | Go to Step 14 | --
13 | Replace the adapter case AT internal transmission wiring harness. Refer to Control Valve Body . Is the action complete? | -- | Go to Step 14 | --
14 | Perform the following procedure to verify the repair:

1. Clear the DTCs with the Scan Tool .
2. Turn OFF the ignition for at least 30 seconds.
3. Start the engine.

Did DTC P1625 reset?

--

Go to Step 1

System OK