C21AC Trouble Code

View C21AC obd/2 error code description and symptoms. C21AC engine photo

Output Shaft Speed sensor circuit intermittent failure The output shaft speed sensor signal to the PCM is irregular or interrupted.
Harness connector not properly seated Harness intermittently shorted, or open Harness connector damaged OSS sensor damaged, or not installed properly Verify harness and connector integrity Verify OSS sensor proper installation.

One example of this would be when an automatic vehicle in placed in gear. To prevent the added drag from the torque converter and transmission from reducing the idling speed, the PCM will command the idle control valve to allow more air to enter the engine, while at the same time, adjusting the injector pulse width to inject more fuel to suit the increased amount of air. Note that the idle air control valve is closed by the PCM when the throttle plate is opened to prevent excess air from entering the engine.

C21AC Error Code Repair Process :

The rule of C21AC code when it comes to emissions-related vehicle repair is that any modification that changes the vehicle from a certified configuration to a non-certified configuration is considered tampering: this applies to both vehicle owners and repair facilities and is, therefore, a Federal offense. Replacing a catalyst with a straight pipe is one traditional example of idm input circuit malfunction/ ignition coil control circuit high voltage. Likewise, overriding the OBD C21AC error in system through the use of high-tech defeat devices or non-certified computer chips, for example, would also be considered tampering. The OBD system may, however, be repaired back to its original certified configuration with certified performance chips or appropriate aftermarket parts.

C21AC is a kind of Chassis Trouble Code

Diagnosing chassis noises can be one of the most frustrating problems technicians face. Fortunately, manufacturers have engineered noise, vibration and harshness (NVH) diagnostic techniques and equipment to find the source of the noise.

Common Causes of C21AC

A common cause of code C21AC is the failure of IDM Input Circuit Malfunction/ Ignition Coil Control Circuit High Voltage, but there are several other possible causes as well, such as ;

Camshaft Position Sensor harness is open or shorted
Faulty Camshaft Position Sensor
Failures of clutch motion/travel sensors.
Faulty starter motor

C21AC code for all cars

You can view according C21AC DTC for your car model. We selected several models to see obd2 solutions click and view it.

+C21AC Pontiac Tempest

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