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.
This diagnostic procedure supports the following DTC:
DTC 1884 Ratio Control Motor Coil A2 Control Circuit
• | 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 4-3 gear shift is active. |
• | Immediately after the above condition occurs. |
• | The hold lamp will blink. |
• | 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. |
• | Open lock-up clutch. |
• | The hold lamp 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. |
When DTC P1884 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 | |
2 |
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 for the 1.6L (L91) engine or to Diagnostic Starting Point - Engine Controls for the 1.8L (L79) engine. Did you find and correct the condition? | -- | Go to Step 6 | Go to Step 4 |
4 |
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 |
Has the last test failed or is the current DTC displayed? | -- | Go to Step 7 | System OK |
7 | Repair or replace the transaxle assembly as necessary. Refer to Transmission Replacement . Is the action completed? | -- | Go to Step 8 | -- |
8 |
Has the last test failed or is the current DTC displayed? | -- | Go to Step 2 | System OK |
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.
• | 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 4-3 gear shift is active. |
• | Immediately after the above condition occurs. |
• | 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. |
• | Open lock-up clutch. |
• | 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. |
When DTC P1884 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 | |
2 |
Did you find and correct the condition? | -- | Go to Step 6 | Go to Step 3 |
3 | Inspect the engine control module. Refer to Diagnostic Starting Point - Engine Controls for the 1.6L (L91) engine or to Diagnostic Starting Point - Engine Controls for the 1.8L (L79) engine. Did you find and correct the condition? | -- | Go to Step 6 | Go to Step 4 |
4 |
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 |
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 . Did you complete the replacement? | -- | Go to Step 8 | -- |
8 |
Has the last test failed or is the current DTC displayed? | -- | Go to Step 2 | System OK |