Harsh or slipping shifts: Codes, Causes & Fixes
Harsh, delayed or slipping shifts in an automatic transmission often trace back to low or degraded fluid, a faulty shift or pressure control solenoid, a speed sensor problem or adaptive shift values that need relearning. Related codes sit mainly in the P07xx range, such as P0700 (transmission control system fault requested) and gear ratio codes P0730–P0736. Avoid heavy loads and long drives until the cause is known, because slipping quickly wears clutches and bands.
80Codes
3.1Average severity
23%High or critical
5%DIY-friendly
Severity distribution
Most viewed
P0218
Powertrain
The transmission fluid got hotter than the computer allows, from heavy load, low fluid…
High
P0730
Powertrain
The transmission computer sees input and output shaft speeds that don't fit the gear it…
High
P0500
Powertrain
The engine computer lost its vehicle speed signal – speedometer, shifting and cruise control…
Moderate
P0756
Powertrain
Solenoid B isn't moving fluid the way the TCM expects – the car may pull away in 3rd or 4th.
High
P0700
Powertrain
The transmission computer found a fault and asked for the check engine light – read the TCM…
Moderate
P0741
Powertrain
The torque converter lockup clutch slips or won't engage when the computer commands it.
Moderate
All codes (70)
U0073
Network
A module saw so many errors on CAN bus A that it shut off its own transmitter.
High
U0100
Network
Another module stopped hearing from the engine computer on the CAN network.
High
U0101
Network
The engine computer and other modules stopped hearing from the transmission control module.
High
U0102
Network
Other modules can't hear the 4WD transfer case module, so 4WD shifting is disabled.
Moderate
U0103
Network
The electronic shifter (dial, knob or joystick) stopped talking to the transmission and engine…
High
U0121
Network
Other modules stopped receiving data from the ABS module, so ABS and stability control are off.
Moderate
U0401
Network
The engine computer is still on the network, but another module doesn't trust the numbers it's…
Moderate
U0402
Network
The transmission module is online, but the gear, range or torque data it sends doesn't add up.
Moderate
U0404
Network
The electronic shifter reports a lever position the transmission can't trust, so Park may not…
High
U0415
Network
The ABS module is online, but the wheel-speed data it shares looks wrong to the other modules.
Moderate