P0A21 Trouble Code

View P0A21 obd/2 error code description and symptoms. P0A21 engine photo

The input turbine speed sensor detects rotation of the input shaft of the input shaft speed sensor transmission. The computer uses that information, along with the output shaft speed sensor to determine if the transmission is operating according to plan. If the computer detects a difference between the input shaft speed , and the expected output shaft speed, it will adjust transmission pump pressure to prevent clutch disc slip. If adding pressure doesn't solve the problem, it will set a trouble code.

A good starting point in your diagnosis is checking all system fuses and fusible links. This can be done using the DVOM on the voltage setting. You will want to test the fuses with circuits loaded. Some fuses will appear normal until a load is placed on their respective circuit; at which point they will fail. This has been the cause of many 'phantom malfunctions'. Consult your vehicle information source for fuse and fusible link locations. If all fuses are in working order, you may want to check TCM relay operation by swapping identical relays. Usually the horn relay, starter relay, fuel pump relay, air conditioning clutch relay, and controller relays are similar enough in design to swap for diagnostic purposes.

P0A21 Error Code Repair Process :

If your hazard flash output circuit open check engine light is illuminated, it's best to take it in for diagnostic testing, which can feel like a hassle. Because while the lights vary in appearance from vehicle to vehicle, all have the same basic meaning: There's a problem with the car's emissions system. The on-board diagnostics system P0A21 and engine control unit are in charge of monitoring a bunch of different hazard flash output circuit open, and if they get a reading that's a little out of whack, up pops the check engine light.

P0A21 is a kind of Powertrain Trouble Code

Powertrain of a modern automobile, comprising engine (with exhaust system), transmission, drive shaft, suspension and the wheels. In a motor vehicle, the term powertrain or powerplant describes the main components that generate power and deliver it to the road surface, water, or air.

Common Causes of P0A21

A common cause of code P0A21 is the failure of Hazard Flash Output Circuit Open, but there are several other possible causes as well, such as ;

Faulty Air Flow Meter
Faulty Camshaft Position Sensor
EVAP system hose leaking
Incorrect Positive Crankcase Ventilation (PCV) hose connection

P0A21 code for all cars

You can view according P0A21 DTC for your car model. We selected several models to see obd2 solutions click and view it.

Engine OBD 2 Codes website is a freeware resource center for engine trouble codes.

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