1999 Astra G X18XE1 AF17 Automatic – Intermittent P0730, Delayed 1-2 Shift, No Upshift at WOT, Limp Mode

1999 Opel Astra G X18XE1 Automatic (AF13-II / AF17 / AF20 / AF22) – Intermittent P0730

Hi everyone,

I'm looking for help diagnosing an intermittent automatic transmission problem on my 1999 Opel Astra G 1.8 (X18XE1) with the AF13-II / AF17 / AF20 / AF22 transmission family.

I bought the car used, and it already had this problem. Unfortunately, I don't know the transmission's repair or service history.

Symptoms:

- Occasionally the 1→2 shift is delayed.
- Sometimes at full throttle, the transmission does not upshift and the engine revs to around 6500 RPM.
- If I slightly lift my foot off the accelerator, it upshifts immediately.
- Sometimes the transmission goes into Limp (Emergency) Mode.
- After switching the ignition OFF and ON, the transmission exits Limp Mode and works normally again until the fault happens again.
- The only transmission DTC recorded is P0730 (Incorrect Gear Ratio). After restarting, it is usually stored as History / Not Present.

Live data observations:

- I recorded several driving sessions under light, medium, and higher load.
- I monitored Engine Speed, Turbine Speed, Output Speed, Shift Solenoids, Line Pressure, Pressure Regulator Current, Torque Converter Slip, TPS, and other transmission data.
- At the exact moment Limp Mode becomes active, Pressure Regulator Current drops to 0 mA, while calculated line pressure increases to about 5 bar.
- Before Limp Mode, the shift solenoids often stay in the 00 state for a short period.

Has anyone experienced this type of intermittent P0730 on this transmission family, or seen similar symptoms?

Any advice or similar experiences would be greatly appreciated. Thank you.
 
Note about the shift solenoid notation used in my logs:

For simplicity, I recorded the two shift solenoids as a two-digit code.

- The first digit represents Shift Solenoid 1 (SS1).
- The second digit represents Shift Solenoid 2 (SS2).

In my logs:

- 1 = Solenoid Active (ON)
- 0 = Solenoid Inactive (OFF)

Therefore:

- 11 = SS1 ON, SS2 ON
- 10 = SS1 ON, SS2 OFF
- 01 = SS1 OFF, SS2 ON
- 00 = SS1 OFF, SS2 OFF

This notation is only used to simplify the Live Data logs.
 
Terug
Naar boven