For 1990-2009 cars

## DTC P1881 Non-Europe or N. American Emissions

### Circuit Description

The pressure control valves 3, 4, 5, and 6 are precision electronic pressure regulators that control the operation of the clutches, brakes and lock-up clutch.

The valve reduces the system pressure with which the downstream solenoid valves and electrical pressure regulating valves are supplied. It is possible to use smaller solenoid valves as a result. The pressure control solenoid valves require a constant input pressure.

### Conditions for Setting the DTC

• | No DTC P1871.

• | Immediately after the above condition occurs.

### Action Taken When the DTC Sets

• | The malfunction indicator lamp (MIL) will illuminate.

• | The transmission control module (TCM) will record operating conditions at the time the diagnostic fails. This information will be stored in the Failure Records buffer.

• | Adopt Emergency/Substitute mode and constant 4th gear.

• | Power supply cut off to the pressure control solenoid valve.

### Conditions for Clearing the MIL/DTC

• | The MIL will turn OFF when the malfunction has not occurred after 3 ignition cycles.

• | A history DTC will clear after 40 consecutive warm-up cycles without a fault.

• | Using a scan tool can clear history DTCs.

### Diagnostic Aids

When DTC P1874 sets, the possible cause of the fault could be the solenoid valve power supply line.

#### DTC P1874

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Install the scan tool.
2. Turn the ignition ON, with the engine OFF.
3. Start the engine and allow the engine to warm up at idle.
4. Put the gear selector in Park and set the parking brake.
5. Observe "solenoid 1,2" on the scan tool.

Is the solenoid ON?

--

Go to Diagnostic Aids

Go to Step 3

3 |

1. Turn the ignition OFF.
2. Disconnect the transaxle wiring connector and the transmission control module (TCM) connector.
3. Measure the voltage of the transaxle wiring terminal 3.

Is the voltage within the specified value?

11-14 V

Go to Step 4

Go to Step 5

4 | Repair the circuit for a short to power. Is the action complete? | -- | System OK | --
5 |

1. Remove the oil pan.
2. Disconnect the solenoid 1 2 wiring connector.
3. Turn the ignition ON, with the engine OFF.
4. Measure the voltage of the solenoid 1 terminal 2.
5. Measure the voltage of the solenoid 2 terminal 2.

Is the voltage within the specified value?

11-14 V

Go to Step 6

Go to Step 7

6 | Repair the circuits for a short to power. Is the action complete? | -- | System OK | --
7 | Replace the TCM. Refer to Transmission Control Module Replacement . Is the action complete? | -- | Go to Step 8 | --
8 |

1. After the repair, use a scan tool "clear info" function and road test the vehicle.
2. Review the "DTC info".

Has the last test failed or is the current DTC displayed?

--

Go to Step 2

System OK

## DTC P1881 European and N. American Emissions

### Circuit Description

The 4HP 16 Auto Transaxle operates without freewheels. Shifting between individual gears takes place by means of overlapping clutch engagement and release.

The advantages of overlap shifting include the following features:

• | The transaxle can be more compactly designed and lighter because of the absence of freewheels and the lower number of shift elements.

• | Lower drag losses, resulting in higher efficiency

• | Lower peak torque acting on the components and the driveline

However, overlap shifting requires high-performance hardware and software and precision engine signals.

### Conditions for Setting the DTC

• | The transmission oil temperature is greater than -10°C (+14°F).

• | The selector lever is not in Neutral or Park position.

• | System voltage is greater than 9 volts.

• | No input speed error DTCs P0715, P0716, or P0717.

• | Output speed is greater than 256 RPM.

• | Input speed is greater than 400 RPM.

• | The 2-1 gear shift is active.

• | Immediately after the above condition occurs

### Action Taken When the DTC Sets

• | The malfunction indicator lamp (MIL) will illuminate.

• | The transmission control module (TCM) will record operating conditions at the time the diagnostic fails. This information will be stored in the Failure Records buffer.

• | Adopt Emergency/Substitute mode and constant 3rd gear.

• | Open lock-up clutch

### Conditions for Clearing the MIL/DTC

• | The MIL will turn OFF when the malfunction has not occurred after 3 ignition cycles.

• | A history DTC will clear after 40 consecutive warm-up cycles without a fault.

• | Using a scan tool can clear history DTCs.

### Diagnostic Aids

When DTC P1881 sets, the possible cause of fault could be TCM.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Install the scan tool.
2. Turn the ignition ON, with the engine OFF. Then, start engine and allow the engine to warm up at idle.
3. Observe Idle RPM, TPS on the scan tool.

Did you find and correct the condition?

--

Go to Step 6

Go to Step 3

3 | Inspect the engine control module (ECM). Refer to Diagnostic Starting Point - Engine Controls . Did you find and correct the condition? | -- | Go to Step 6 | Go to Step 4
4 |

1. Turn the ignition OFF.
2. Disconnect the transmission control module wiring connector.
3. Measure the voltage between terminal B3 and B13 of the transaxle wiring connector.
4. Turn the ignition ON, with the engine OFF.
5. Measure the voltage between terminal C15 and B13 of the transaxle wiring connector.
6. Measure the voltage between terminal C16 and B13 of the transaxle wiring connector.

Is the voltage within the specified value?

11-14 V

Go to Step 5

Go to DTC P0562

or

Go to DTC P0563

5 | Replace the TCM. Refer to Transmission Control Module Replacement . Is the action complete? | -- | Go to Step 6 | --
6 |

1. After the repair, use a scan tool Clear Info function and road test the vehicle.
2. Review the DTC Info.

Has the last test failed or is the current DTC displayed?

--

Go to Step 7

System OK

7 | Repair or replace the transaxle assembly. Refer to Transmission Replacement . Is the action complete? | -- | Go to Step 8 | --
8 |

1. After the repair, use a scan tool Clear Info function and road test the vehicle.
2. Review the DTC Info.

Has the last test failed or is the current DTC displayed?

--

Go to Step 2

System OK