U21AU Honda Concerto DTC Code

Honda Concerto Engine Specifications:

Engine Type :	Single Cylinder Engine
Cylinder Type :	Opposed Cylinder Engine
Engine Air Intake Process :	Naturally Aspirated

Your Honda Concerto engine control system detects a problem, the computer stores the diagnostic trouble code U21AU in its memory. To figure out what is wrong with your vehicle you must first extract the U21AU DTC For Honda Concerto.

On 1999 and later U21AU Honda Concerto engines, the instrument cluster has a built-in self-diagnostic mode that can be accessed by pressing and holding the instrument cluster SELECT/RESET button. Insert the ignition key and turn to the RUN position (but don't crank or start engine). Continue to press and hold the SELECT/RESET button (for 5 seconds) until the word TEST is displayed by the odometer. Release the SELECT/RESET button within three seconds after the word TEST is displayed to begin the self-diagnostic mode.

U21AU Honda Concerto DTC Meaning

U	Network Code - Problem is climate control system, lighting, airbags, etc.
2	MFG - Manufacturer Specific
1	Fuel And Air Metering
A	BBV Sensor Circuit Low Voltage
U	TFP Valve Position Switch-Drive Without Drive Ratio

While fuel economy was increased, acceleration was seriously compromised, and the loss of engine vacuum led to a dangerous loss of braking assist when the U21AU Honda Concerto code system was in four-cylinder mode. In addition to these issues, while the company proposed a hydraulically controlled system that could be switched from within the car, the version they implemented had to be manually changed in the engine compartment using hand tools.