Fault code P0730 – a step-by-step guide to diagnosing and fixing it

Error code P0730 is displayed and the check engine light is on - what does this mean?

With DTC P0730, the OBD-II system detects an error in the automatic transmission in which the transmission control unit detects an incorrect transmission ratio. This error code affects the entire transmission system and can be interpreted differently for different manufacturers, although the basic problem remains the same for all vehicles.

What can cause this error code?

• Worn or damaged clutches in the automatic transmission
• Defective solenoid valves (solenoids) in the transmission
• Low or contaminated transmission oil level
• Clogged transmission oil filter
• Faulty transmission control unit (TCM)
• Defective speed sensors in the transmission
• Mechanical damage to gearwheels or planetary gears
• Leaking hydraulic lines in the transmission
• Worn seals and pistons

What symptoms occur in parallel with error code P0730?

• Shifting problems: The transmission shifts jerkily or not at all
• Slipping gears: The vehicle does not accelerate despite high engine speed
• Delayed engagement: Gears are only engaged with a delay
• Unusual noises: Whistling or grinding noises from the transmission
• Emergency running program: The transmission only works in one gear
• Increased fuel consumption: Due to inefficient power transmission
• Jerking when starting off: Especially from a standstill

How can the problem with error code P0730 be rectified?

• Repairing trouble code P0730 requires a systematic approach to the transmission system.
• Change the transmission oil: Completely replace the automatic transmission fluid, including the filter, to remove contamination and restore hydraulic function
• Replace solenoid valves: Replace defective solenoids in the transmission, which are responsible for gear shifting
• Repair transmission control unit: Check TCM module and reprogram or replace if necessary
• Replace speed sensors: Check the function of the input speed sensor and output speed sensor and replace them
• Repair hydraulic system: Repair leaking lines, valve bodies or pistons in the transmission
• Transmission overhaul: In the event of serious mechanical damage, complete general overhaul of the automatic transmission