C3971 Trouble Code

View C3971 obd/2 error code description and symptoms. C3971 engine photo

The Transmission Fluid Pressure Switch allows the engine's control module (PCM) or Transmission Control Module (TCM) to use hydraulic fluid to engage the clutches in the transmission to allow for smoother shifting while driving. If the PCM or TCM detects an issue with the hydraulic clutch or the pressure switch, the PCM or TCM will set code C3971

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.

C3971 Error Code Repair Process :

If your vehicle failed a C3971 test and the C3971 Check Engine Light is NOT on, chances are you have a problem with the OBDII system, a burned out MIL lamp, or a faulty catalytic converter. The converter is essentially an afterburner that cleans up the exhaust after it exits the engine. The OBDII system uses air suspension disable switch circuit open a ownstream oxygen sensor to monitor the efficiency of the converter, and it should detect a drop in converter efficiency if the converter has been contaminated or is failing (ignition misfiring, leaky exhaust valves, and oil burning can all damage the converter). What you want to look air suspension disable switch circuit open: Any conditions that might cause ignition misfire, an overly rich or lean fuel condition, or loss of compression. Use your OBD Express DIY to look at the oxygen sensor outputs, coolant temperature, airflow, calculated engine load, and inlet air temperature.

C3971 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 C3971

A common cause of code C3971 is the failure of Air Suspension Disable Switch Circuit Open, but there are several other possible causes as well, such as ;

Continuous oil flow to the VCT piston chamber
Damaged ECM
Fuel injectors harness is open or shorted
Starting system circuit Dead (Weak) battery

C3971 code for all cars

You can view according C3971 DTC for your car model. We selected several models to see obd2 solutions click and view it.

+C3971 Citroen C4 Aircross

+C3971 Zis 112

+C3971 Fiat 1900

+C3971 Opel Crossland X

+C3971 Zastava 132

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