WHAT IS AUTOMATIC TRANSMISSION?
Automatic transmission is a mechanism that helps the driver by changing the drive gears to raise or lower wheel speed for a given engine RPM, gradually transmitting engine power.
Fault codes may indicate a specific point inside the transmission or indirectly point to related faults elsewhere. Diagnosis must be done with a suitable, up-to-date diagnostic tool.
There are five main transmission types: DSG, CVT, EDC, MMT and TCT Dualogic Easytronic.
In automatic transmissions, these parts commonly fail:
Torque converter, oil pump, clutch packs, transmission housing, planetary gear sets, hydraulic valve body, electronic control parts and transmission seals.
Common causes of automatic transmission failure:
Wrong fluid is the biggest factor. Fluid that does not match the vehicle causes oxidation damage to the transmission and hydraulic ECU.
Hard braking and acceleration while the gearbox shifts automatically stresses the gears. Tiptronic cars see more user-related faults. Shifting up without reaching proper RPM lowers performance and damages the transmission ECU.
Incorrect shifts are a major issue: the shift lock must be pressed before changing gear. Shifting without it shortens component life and can break parts.
Skipping transmission service leads to fluid leaks and shuddering.
Automatic transmission fault symptoms:
On level or downhill roads in "D" with the brake released, the vehicle should creep forward.
Uphill in "D" with the brake released, the vehicle should hold without rolling back.
While moving in "D" there should be no noise, vibration or shudder between shifts.
The shift lock (mandrel) must work smoothly; occasional sticking indicates a problem linked to the torque converter.
Transmission noise should stay stable in all gears without unusual whine or vibration.
Poor acceleration on hills or reduced pulling power also suggests a transmission fault.
Automatic Transmission Fault Codes
Automatic transmission codes are largely universal but may vary slightly by brand.
P0785 – Shift/timing solenoid A malfunction
First check ATF (automatic transmission fluid). If it is dirty, burnt, overfilled or discoloured, change the fluid.
Test the shift timing solenoid and the circuit from the TCM to verify sensor operation.
Leaving this unresolved can cause serious, hard-to-repair damage and may require transmission replacement – do not ignore this code.
Automatic Transmission P-Code Faults
P0701: Transmission Control System Range/Performance
P0702: Transmission Control System Electrical
P0703: Brake Switch Input Malfunction
P0704: Clutch Switch Input Circuit Malfunction
P0705: Transmission Range Sensor Circuit Malfunction
P0706: Transmission Range Sensor Circuit Range/Performance
P0707: Transmission Range Sensor Circuit Low Input
P0708: Transmission Range Sensor Circuit High Input
P0709: Transmission Range Sensor Circuit Intermittent
P0710: Transmission Fluid Temperature Sensor Circuit Malfunction
P0711: Transmission Fluid Temperature Sensor Circuit Range/Performance
P0712: Transmission Fluid Temperature Sensor Circuit Low Input
P0713: Transmission Fluid Temperature Sensor Circuit High Input
P0714: Transmission Fluid Temperature Sensor Circuit Intermittent
P0715: Input/Turbine Speed Sensor Circuit Malfunction
P0716: Input/Turbine Speed Sensor Circuit Range/Performance
P0717: Input/Turbine Speed Sensor Circuit No Signal
P0718: Input/Turbine Speed Sensor Circuit Intermittent
P0719: Torque Converter/Brake Switch B Circuit Low
P0720: Output Speed Sensor Circuit Malfunction
P0721: Output Speed Sensor Circuit Range/Performance
P0722: Output Speed Sensor Circuit No Signal
P0723: Output Speed Sensor Circuit Intermittent
P0724: Torque Converter/Brake Switch B Circuit High
P0725: Engine Speed Input Circuit Malfunction
P0726: Engine Speed Input Circuit Range/Performance
P0727: Engine Speed Input Circuit No Signal
P0728: Engine Speed Input Circuit Intermittent
P0730: Incorrect Gear Ratio
P0731: Gear 1 Incorrect Ratio
P0732: Gear 2 Incorrect Ratio
P0733: Gear 3 Incorrect Ratio
P0734: Gear 4 Incorrect Ratio
P0735: Gear 5 Incorrect Ratio
P0736: Reverse Incorrect Ratio
P0740: Torque Converter Clutch Circuit Malfunction
P0741: Torque Converter Clutch Circuit Performance or Stuck Off
P0742: Torque Converter Clutch Circuit Stuck On
P0743: Torque Converter Clutch Circuit Electrical
P0744: Torque Converter Clutch Circuit Intermittent
P0745: Pressure Control Solenoid A Malfunction
P0746: Pressure Control Solenoid A Performance or Stuck Off
P0747: Pressure Control Solenoid A Stuck On
P0748: Pressure Control Solenoid A Electrical
P0749: Pressure Control Solenoid A Intermittent
P0750: Shift Solenoid A Malfunction
P0751: Shift Solenoid A Performance
P0752: Shift Solenoid A Stuck On
P0753: Shift Solenoid A Electrical
P0754: Shift Solenoid A Intermittent
P0755: Shift Solenoid B Malfunction
P0756: Shift Solenoid B Performance
P0757: Shift Solenoid B Stuck On
P0758: Shift Solenoid B Electrical
P0759: Shift Solenoid B Intermittent
P0760: Shift Solenoid C Malfunction
P0761: Shift Solenoid C Performance
P0762: Shift Solenoid C Stuck On
P0763: Shift Solenoid C Electrical
P0764: Shift Solenoid C Intermittent
P0765: Shift Solenoid D Malfunction
P0766: Shift Solenoid D Performance
P0767: Shift Solenoid D Stuck On
P0768: Shift Solenoid D Electrical
P0769: Shift Solenoid D Intermittent
P0770: Shift Solenoid E Malfunction
P0771: Shift Solenoid E Performance
P0772: Shift Solenoid E Stuck On
P0773: Shift Solenoid E Electrical
P0774: Shift Solenoid E Intermittent
P0775: Pressure Control Solenoid B Malfunction
P0776: Pressure Control Solenoid B Performance
P0777: Pressure Control Solenoid B Stuck On
P0778: Pressure Control Solenoid B Electrical
P0779: Pressure Control Solenoid B Intermittent
P0780: Shift Malfunction
P0781: 1-2 Shift Malfunction
P0782: 2-3 Shift Malfunction
P0783: 3-4 Shift Malfunction
P0784: 4-5 Shift Malfunction
P0785: Shift/Timing Solenoid Malfunction
P0786: Shift/Timing Solenoid Range/Performance
P0787: Shift/Timing Solenoid Low
P0788: Shift/Timing Solenoid High
P0789: Shift/Timing Solenoid Intermittent
These are common automatic transmission fault codes. Unsure what to do when you see them?
AUTODATA repair data, parts catalogue, fault codes and SENTE software online can help you work faster.
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